diff --git a/AGENTS.md b/AGENTS.md
index c41d771..f8ca4ad 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -30,15 +30,16 @@ There is no separate lint command. CI (`.github/workflows/sdk_ci.yml`) runs `npm
 
 ## Conventions
 
+- **Exactly the documented set of fields, no more and no fewer.** The eight S3 / SFTP file jobs go through `_bulkRootFileJob` and send `file_name`, `has_header_row`, `remove_duplicates` and `return_url` only. The live API requires `file_name` and `return_url` on every one of them, including `validateSFTPfile`, although the docs mark them optional.
 - **Only endpoints documented at https://www.zerobounce.net/docs/.** Do not add a method for an endpoint that the public docs do not describe, even if it exists on the server. Check before concluding something is undocumented: the S3 bulk endpoints live under https://www.zerobounce.net/docs/api-integrations/amazon-s3-bulk-api, not the main API reference.
 - **One `ZeroBounceSDK` per API key.** The key is stored on the instance. Do not reuse one instance across users or requests. Construct a separate object per key. The offline concurrency test does this.
 - **Column indexes are 1-based and are not converted.** Optional name, gender, and IP columns use `0` or `false` to mean "leave this field out". Required `email_address_column` and `domain_column` are sent as given, including `0`. `0` is not "missing".
 - **Optional parameters are omitted when unset.** `timeout`, `activityData`, `verifyPlus`, `allowPhase2`, `downloadType`, `ip_address`, and email-finder name fields are not sent until the caller sets them. Explicit `false` is sent as the string `false` on query, form, and multipart bodies, and as a JSON boolean on `validateBatch`.
 - **Do not use boolean `false` as the "omit this column" sentinel inside `_sendBulkRootMultipartFile`.** `false` is a real `has_header_row` value and must be appended as `"false"`. Optional columns that are unset are `null`, and `null` is omitted. `optionalColumn` turns `0` and `false` into `null` for those optional columns only.
-- **`allow_phase_2` is validation bulk only** (`sendFile`, `sendFileStream`, `validateS3file`), and only when `allowPhase2` is set. Scoring `sendFile` ignores it. `activity_data` on get-file is validation `getFile` only.
-- **List evaluator and the Inbox Placement Tester have their own base URLs**, set on the instance by `init`'s third argument: `https://bulkapi.zerobounce.net/v2/listevaluator` and `https://bulkapi.zerobounce.net/api/ipt`. They are not built from the bulk base. `sendEvaluatedFile` stays on the bulk `/v2` base.
+- **`allow_phase_2` is validation bulk only** (`sendFile`, `sendFileStream`), and only when `allowPhase2` is set. Scoring `sendFile` ignores it. The S3 and SFTP file jobs send only the documented set and so never send it. `activity_data` on get-file is validation `getFile` only.
+- **List evaluator, the Inbox Placement Tester, the bulk email finder and bulk domain search have their own base URLs**, set on the instance by `init`'s third argument: `https://bulkapi.zerobounce.net/v2/listevaluator`, `https://bulkapi.zerobounce.net/api/ipt`, `https://bulkapi.zerobounce.net/email-finder` and `https://bulkapi.zerobounce.net/domain-search`. They are not built from the bulk base, and each is passed to `createRequest` as `baseURL` with a path relative to it. `sendEvaluatedFile` stays on the bulk `/v2` base.
 - **The Inbox Placement Tester takes the API key as the `api_key` query parameter and JSON bodies with camelCase fields.** Only fields the caller set are sent. Its error bodies use `detail`.
-- **`validateBatch` uses `api.zerobounce.net`**, not `bulkapi.zerobounce.net`. Bulk email finder and domain search use the bulk host root (`/email-finder/…`, `/domain-search/…`) with no `/v2`. List evaluator and validation/scoring file methods use `https://bulkapi.zerobounce.net/v2`.
+- **`validateBatch` uses `api.zerobounce.net`**, not `bulkapi.zerobounce.net`, and sends its body as `jsonBody` so `createRequest` sets `Content-Type: application/json`. Bulk email finder and domain search use the bulk host root (`/email-finder/…`, `/domain-search/…`) with no `/v2`. List evaluator and validation/scoring file methods use `https://bulkapi.zerobounce.net/v2`.
 - **Failures reject the promise.** The message must be short: no raw HTML, no megabyte body, no `SyntaxError` / `Unexpected token` text, and no `Error: Error:` or `[Error]:` prefix. An account-level `validateBatch` error (`email_address` `all`) rejects. A per-address error stays on the resolved result. A top-level `error` string for an invalid API key or no credits rejects. `{ error: "invalid email" }` from `scoreEmail` stays on the result. A bulk JSON body such as `{ success: "False", message: […] }` is returned when it is not one of those account-level `error` strings.
 - **`getFile` in a browser** downloads the CSV and resolves to the filename. **In Node** it resolves to the CSV text. A JSON error body (for example `success: false`) is returned as the parsed object. HTML, an empty body, and HTTP status 400 or higher reject.
 - **`init` requires an `https://` base URL** and a non-blank API key. Requests time out after 120 seconds. `fetch` is called with `redirect: "error"`.
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 88d0709..36aeb45 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -7,6 +7,20 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
+### Changed
+
+- `init`'s `emailFinderBaseURL` and `domainSearchBaseURL` options are now honoured. They were validated and stored but never read, so the bulk email finder and bulk domain search always went to `https://bulkapi.zerobounce.net`. Both default to the same hosts as before, so a client that does not set them is unaffected.
+- **BREAKING:** `sendEmailFinderFile` and `sendEmailFinderFileStream` require `first_name_column` or `full_name_column`, as the bulk email finder documents. As with every optional column, `0` and `false` mean "leave this column out" and so do not count as given.
+- **BREAKING:** `validateS3file` and `scoreS3file` now send exactly the documented job fields — `file_name`, `has_header_row`, `remove_duplicates` and `return_url` — and go through the same path as their six siblings. They no longer send the undocumented `email_address_column`, `first_name_column`, `last_name_column`, `gender_column`, `ip_address_column`, `allow_phase_2` or singular `remove_duplicate`. `file_name`, `has_header_row` and `return_url` are now required on both: the live API rejects a job without `return_url` ("Provided return URL is not permitted: None"). `allowPhase2` remains available on `sendFile` and `sendFileStream`.
+- `findEmailByDomain` and `findEmailByCompanyName` accept a missing `first_name` instead of rejecting it, as the Email Finder documents it as optional. Without it the API answers with the domain's or company's email format. `domain` or `company_name` is still required.
+- `exportS3file` accepts a missing `export_bucket` instead of rejecting it, matching `exportSFTPfile`'s `export_path`. Without it the output bucket from your ZeroBounce settings is used.
+
+### Fixed
+
+- `validateBatch` sends its JSON body with `Content-Type: application/json`. It was handed to `fetch` as a plain string, which labelled the JSON `text/plain;charset=UTF-8`.
+- Warmup `addSendingAccount` rejects `engagementRuleId` for a `zb_managed` account rather than silently dropping it. The field belongs to `self_managed` only.
+- `validateSFTPfile` no longer passes a third argument that the shared job helper never had, and its documentation no longer says `file_name` is optional — the live API requires it.
+
 ## [3.0.0] - 2026-10-25
 
 This release is a major version because the error contract changed: every public
diff --git a/README.md b/README.md
index eb3d327..45339a4 100644
--- a/README.md
+++ b/README.md
@@ -141,8 +141,27 @@ try {
 - ##### S3 and SFTP/FTP bulk jobs
 
 ```javascript
+// All eight jobs take the same four fields and nothing else: file_name,
+// has_header_row, remove_duplicates and return_url. The live API requires
+// file_name and return_url on every one of them, including validateSFTPfile,
+// although the docs mark them optional.
+
 // Amazon S3: https://www.zerobounce.net/docs/api-integrations/amazon-s3-bulk-api
-await zeroBounce.emailFinderS3file({ file_name: "lists/leads.csv", has_header_row: true });
+await zeroBounce.validateS3file({
+  file_name: "lists/leads.csv",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+});
+await zeroBounce.scoreS3file({
+  file_name: "lists/leads.csv",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+});
+await zeroBounce.emailFinderS3file({
+  file_name: "lists/leads.csv",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+});
 await zeroBounce.domainSearchS3file({
   file_name: "lists/leads.csv",
   has_header_row: true,
@@ -150,18 +169,46 @@ await zeroBounce.domainSearchS3file({
   return_url: "https://example.com/zerobounce-done",
 });
 
+// Without export_bucket the output bucket from your settings is used.
+await zeroBounce.exportS3file({ file_id: "<FILE_ID>" });
+await zeroBounce.exportS3file({ file_id: "<FILE_ID>", export_bucket: "my-bucket" });
+
 // SFTP/FTP: https://www.zerobounce.net/docs/api-integrations/sftp_bulk_api
 // The server, path and protocol come from your ZeroBounce settings.
-// file_name is optional for validateSFTPfile only.
-await zeroBounce.validateSFTPfile({ has_header_row: true });
-await zeroBounce.scoreSFTPfile({ file_name: "my_file.txt", has_header_row: true });
-await zeroBounce.emailFinderSFTPfile({ file_name: "my_file.txt", has_header_row: true });
-await zeroBounce.domainSearchSFTPfile({ file_name: "my_file.txt", has_header_row: true });
+const sftpJob = {
+  file_name: "my_file.txt",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+};
+await zeroBounce.validateSFTPfile(sftpJob);
+await zeroBounce.scoreSFTPfile(sftpJob);
+await zeroBounce.emailFinderSFTPfile(sftpJob);
+await zeroBounce.domainSearchSFTPfile(sftpJob);
 
 // Without export_path the path from your settings is used.
 await zeroBounce.exportSFTPfile({ file_id: "<FILE_ID>", export_path: "/exports" });
 ```
 
+- ##### Bulk email finder
+
+```javascript
+// domain_column is required, and so is a name to work from: send either
+// first_name_column or full_name_column. As with every optional column, 0 and
+// false mean "leave this column out", so neither counts as a name column.
+await zeroBounce.sendEmailFinderFile({
+  file: "<FILE>",
+  domain_column: 1,
+  first_name_column: 2,
+  last_name_column: 3,
+  has_header_row: true,
+});
+await zeroBounce.sendEmailFinderFile({
+  file: "<FILE>",
+  domain_column: 1,
+  full_name_column: 2,
+});
+```
+
 - ##### Inbox Placement Tester
 
 ```javascript
@@ -199,11 +246,14 @@ try {
 - ##### Point an API at a different base URL
 
 ```javascript
-// The list evaluator and the Inbox Placement Tester have their own base URLs,
-// separate from the main and bulk hosts.
+// The list evaluator, the Inbox Placement Tester, the bulk email finder and
+// bulk domain search each have their own base URL, separate from the main and
+// bulk hosts. Every one of them must be https://.
 zeroBounce.init("<YOUR_API_KEY>", ZeroBounceSDK.ApiURL.DEFAULT_API_URL, {
   listEvaluatorBaseURL: "https://bulkapi.zerobounce.net/v2/listevaluator",
   inboxPlacementBaseURL: "https://bulkapi.zerobounce.net/api/ipt",
+  emailFinderBaseURL: "https://bulkapi.zerobounce.net/email-finder",
+  domainSearchBaseURL: "https://bulkapi.zerobounce.net/domain-search",
 });
 ```
 
@@ -422,8 +472,9 @@ try {
 //     The email domain for which to find the email format. 
 // company_name: String
 //     The company name for which to find the email format.
-// first_name: String
+// first_name: String or null (Optional)
 //     The first name of the person whose email format is being searched.
+//     Left out, the API answers with the domain's or company's email format.
 // middle_name: String or null (Optional)
 //     The middle name of the person whose email format is being searched.
 // last_name: String or null (Optional)
@@ -446,6 +497,8 @@ const companyNamePayload = {
 try {
   const domainResponse = await zeroBounce.findEmailByDomain(domainPayload);
   const companyNameResponse = await zeroBounce.findEmailByCompanyName(companyNamePayload);
+  // first_name is optional: this asks for the domain's format on its own.
+  const formatOnly = await zeroBounce.findEmailByDomain({ domain: "<DOMAIN>" });
 } catch (error) {
   console.error(error);
 }
diff --git a/documentation.md b/documentation.md
index e3232ef..0691ec2 100644
--- a/documentation.md
+++ b/documentation.md
@@ -95,8 +95,27 @@ try {
 - ##### S3 and SFTP/FTP bulk jobs
 
 ```javascript
+// All eight jobs take the same four fields and nothing else: file_name,
+// has_header_row, remove_duplicates and return_url. The live API requires
+// file_name and return_url on every one of them, including validateSFTPfile,
+// although the docs mark them optional.
+
 // Amazon S3: https://www.zerobounce.net/docs/api-integrations/amazon-s3-bulk-api
-await zeroBounce.emailFinderS3file({ file_name: "lists/leads.csv", has_header_row: true });
+await zeroBounce.validateS3file({
+  file_name: "lists/leads.csv",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+});
+await zeroBounce.scoreS3file({
+  file_name: "lists/leads.csv",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+});
+await zeroBounce.emailFinderS3file({
+  file_name: "lists/leads.csv",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+});
 await zeroBounce.domainSearchS3file({
   file_name: "lists/leads.csv",
   has_header_row: true,
@@ -104,18 +123,39 @@ await zeroBounce.domainSearchS3file({
   return_url: "https://example.com/zerobounce-done",
 });
 
+// Without export_bucket the output bucket from your settings is used.
+await zeroBounce.exportS3file({ file_id: "<FILE_ID>" });
+
 // SFTP/FTP: https://www.zerobounce.net/docs/api-integrations/sftp_bulk_api
 // The server, path and protocol come from your ZeroBounce settings.
-// file_name is optional for validateSFTPfile only.
-await zeroBounce.validateSFTPfile({ has_header_row: true });
-await zeroBounce.scoreSFTPfile({ file_name: "my_file.txt", has_header_row: true });
-await zeroBounce.emailFinderSFTPfile({ file_name: "my_file.txt", has_header_row: true });
-await zeroBounce.domainSearchSFTPfile({ file_name: "my_file.txt", has_header_row: true });
+const sftpJob = {
+  file_name: "my_file.txt",
+  has_header_row: true,
+  return_url: "https://example.com/zerobounce-done",
+};
+await zeroBounce.validateSFTPfile(sftpJob);
+await zeroBounce.scoreSFTPfile(sftpJob);
+await zeroBounce.emailFinderSFTPfile(sftpJob);
+await zeroBounce.domainSearchSFTPfile(sftpJob);
 
 // Without export_path the path from your settings is used.
 await zeroBounce.exportSFTPfile({ file_id: "<FILE_ID>", export_path: "/exports" });
 ```
 
+- ##### Bulk email finder
+
+```javascript
+// domain_column is required, and so is a name to work from: send either
+// first_name_column or full_name_column. As with every optional column, 0 and
+// false mean "leave this column out", so neither counts as a name column.
+await zeroBounce.sendEmailFinderFile({
+  file: "<FILE>",
+  domain_column: 1,
+  first_name_column: 2,
+  has_header_row: true,
+});
+```
+
 - ##### Inbox Placement Tester
 
 ```javascript
@@ -376,8 +416,9 @@ try {
 //     The email domain for which to find the email format. 
 // company_name: String
 //     The company name for which to find the email format.
-// first_name: String
+// first_name: String or null (Optional)
 //     The first name of the person whose email format is being searched.
+//     Left out, the API answers with the domain's or company's email format.
 // middle_name: String or null (Optional)
 //     The middle name of the person whose email format is being searched.
 // last_name: String or null (Optional)
diff --git a/src/warmup.js b/src/warmup.js
index 65a3e05..ce8485f 100644
--- a/src/warmup.js
+++ b/src/warmup.js
@@ -180,8 +180,8 @@ export class ZeroBounceWarmup {
    *
    * `self_managed` runs your own mailbox and needs `engagementRuleId` 0-4.
    * `zb_managed` has ZeroBounce provision it and takes `emailContent` and
-   * `managedSending` instead; a 200 means accepted, and the mailbox is
-   * provisioned afterwards.
+   * `managedSending` instead, and rejects `engagementRuleId`; a 200 means
+   * accepted, and the mailbox is provisioned afterwards.
    */
   addSendingAccount({
     fromAddress,
@@ -204,6 +204,9 @@ export class ZeroBounceWarmup {
       if (emailContent != null || managedSending != null) {
         throw clientError("email_content and managed_sending are for zb_managed.");
       }
+    } else if (engagementRuleId != null) {
+      // zb_managed has no engagement_rule_id field: say so rather than drop it.
+      throw clientError("engagement_rule_id is for self_managed.");
     }
     if (ignoreConflict != null) body.ignore_conflict = Boolean(ignoreConflict);
     if (emailContent != null) {
diff --git a/src/zero-bounce.js b/src/zero-bounce.js
index ab1d2fb..345683c 100644
--- a/src/zero-bounce.js
+++ b/src/zero-bounce.js
@@ -341,7 +341,7 @@ export class ZeroBounceSDK {
     return createRequest({
       requestType: "POST",
       path: "/validatebatch",
-      body: JSON.stringify(body),
+      jsonBody: body,
       apiBaseURL: this._api_base_url
     });
   }
@@ -623,7 +623,7 @@ export class ZeroBounceSDK {
     });
   }
 
-  async _getStatusUtil(fileId, path, { bulkRoot = false } = {}) {
+  async _getStatusUtil(fileId, path, { bulkRoot = false, baseURL = null } = {}) {
     if (!this._initialized) {
       notInitialized();
       return;
@@ -642,7 +642,8 @@ export class ZeroBounceSDK {
       path,
       batch: true,
       bulkBase: bulkRoot ? "root" : "v2",
-      apiBaseURL: this._api_base_url
+      apiBaseURL: this._api_base_url,
+      baseURL
     });
   }
 
@@ -676,7 +677,7 @@ export class ZeroBounceSDK {
     return this._getStatusUtil(fileId, "/scoring/filestatus");
   }
 
-  async _getFileUtil(fileId, path, scoring = false, getFileOptions = null, { bulkRoot = false } = {}) {
+  async _getFileUtil(fileId, path, scoring = false, getFileOptions = null, { bulkRoot = false, baseURL = null } = {}) {
     if (!this._initialized) {
       notInitialized();
       return;
@@ -704,7 +705,8 @@ export class ZeroBounceSDK {
       bulkBase: bulkRoot ? "root" : "v2",
       returnText: true,
       scoring, 
-      apiBaseURL: this._api_base_url
+      apiBaseURL: this._api_base_url,
+      baseURL
     });
   }
 
@@ -724,7 +726,7 @@ export class ZeroBounceSDK {
     return this._getFileUtil(fileId, "/scoring/getfile", true, getFileOptions);
   }
 
-  async _deleteFileUtil(fileId, path, scoring = false, { bulkRoot = false } = {}) {
+  async _deleteFileUtil(fileId, path, scoring = false, { bulkRoot = false, baseURL = null } = {}) {
     if (!this._initialized) {
       notInitialized();
       return;
@@ -743,11 +745,12 @@ export class ZeroBounceSDK {
       batch: true,
       bulkBase: bulkRoot ? "root" : "v2",
       scoring, 
-      apiBaseURL: this._api_base_url
+      apiBaseURL: this._api_base_url,
+      baseURL
     });
   }
 
-  async _sendBulkRootMultipartFile(path, { file, fileName = null, fields = {} }) {
+  async _sendBulkRootMultipartFile(path, { file, fileName = null, fields = {}, baseURL = null }) {
     const body = new FormData();
     for (const [key, value] of Object.entries(fields)) {
       if (value == null) continue;
@@ -766,6 +769,7 @@ export class ZeroBounceSDK {
       batch: true,
       bulkBase: "root",
       apiBaseURL: this._api_base_url,
+      baseURL,
     });
   }
 
@@ -783,8 +787,16 @@ export class ZeroBounceSDK {
     return this._deleteFileUtil(fileId, "/scoring/deletefile", true);
   }
 
-  // BULK EMAIL FINDER (bulkapi.zerobounce.net/email-finder/*)
+  // BULK EMAIL FINDER (emailFinderBaseURL, by default
+  // bulkapi.zerobounce.net/email-finder)
 
+  /**
+   * Submit a file to the bulk email finder. POST /email-finder/sendfile
+   *
+   * The API needs a name to work from: either {@code first_name_column} or
+   * {@code full_name_column}. As with every optional column, {@code 0} and
+   * {@code false} mean "leave this field out", so neither counts as given.
+   * */
   async sendEmailFinderFile({
     file,
     domain_column,
@@ -803,9 +815,13 @@ export class ZeroBounceSDK {
     } else if (isMissing(domain_column)) {
       parameterIsMissing("domain_column");
       return;
+    } else if (!first_name_column && !full_name_column) {
+      parameterIsMissing("first_name_column", "Send first_name_column or full_name_column.");
+      return;
     }
-    return this._sendBulkRootMultipartFile("/email-finder/sendfile", {
+    return this._sendBulkRootMultipartFile("/sendfile", {
       file,
+      baseURL: this._email_finder_base_url,
       fields: {
         domain_column,
         first_name_column: optionalColumn(first_name_column),
@@ -817,6 +833,12 @@ export class ZeroBounceSDK {
     });
   }
 
+  /**
+   * Submit a stream or Blob to the bulk email finder. POST /email-finder/sendfile
+   *
+   * Takes {@code first_name_column} or {@code full_name_column}, as
+   * {@link sendEmailFinderFile} does.
+   * */
   async sendEmailFinderFileStream(fileStreamOrBlob, fileName, {
     domain_column,
     first_name_column = false,
@@ -837,10 +859,14 @@ export class ZeroBounceSDK {
     } else if (isMissing(domain_column)) {
       parameterIsMissing("domain_column");
       return;
+    } else if (!first_name_column && !full_name_column) {
+      parameterIsMissing("first_name_column", "Send first_name_column or full_name_column.");
+      return;
     }
-    return this._sendBulkRootMultipartFile("/email-finder/sendfile", {
+    return this._sendBulkRootMultipartFile("/sendfile", {
       file: fileStreamOrBlob,
       fileName,
+      baseURL: this._email_finder_base_url,
       fields: {
         domain_column,
         first_name_column: optionalColumn(first_name_column),
@@ -853,18 +879,28 @@ export class ZeroBounceSDK {
   }
 
   async getEmailFinderFileStatus(fileId) {
-    return this._getStatusUtil(fileId, "/email-finder/filestatus", { bulkRoot: true });
+    return this._getStatusUtil(fileId, "/filestatus", {
+      bulkRoot: true,
+      baseURL: this._email_finder_base_url,
+    });
   }
 
   async getEmailFinderFile(fileId) {
-    return this._getFileUtil(fileId, "/email-finder/getfile", false, null, { bulkRoot: true });
+    return this._getFileUtil(fileId, "/getfile", false, null, {
+      bulkRoot: true,
+      baseURL: this._email_finder_base_url,
+    });
   }
 
   async deleteEmailFinderFile(fileId) {
-    return this._deleteFileUtil(fileId, "/email-finder/deletefile", false, { bulkRoot: true });
+    return this._deleteFileUtil(fileId, "/deletefile", false, {
+      bulkRoot: true,
+      baseURL: this._email_finder_base_url,
+    });
   }
 
-  // BULK DOMAIN SEARCH (bulkapi.zerobounce.net/domain-search/*)
+  // BULK DOMAIN SEARCH (domainSearchBaseURL, by default
+  // bulkapi.zerobounce.net/domain-search)
 
   async sendDomainSearchFile({
     file,
@@ -881,8 +917,9 @@ export class ZeroBounceSDK {
       parameterIsMissing("domain_column");
       return;
     }
-    return this._sendBulkRootMultipartFile("/domain-search/sendfile", {
+    return this._sendBulkRootMultipartFile("/sendfile", {
       file,
+      baseURL: this._domain_search_base_url,
       fields: { domain_column, has_header_row: Boolean(has_header_row) },
     });
   }
@@ -904,23 +941,33 @@ export class ZeroBounceSDK {
       parameterIsMissing("domain_column");
       return;
     }
-    return this._sendBulkRootMultipartFile("/domain-search/sendfile", {
+    return this._sendBulkRootMultipartFile("/sendfile", {
       file: fileStreamOrBlob,
       fileName,
+      baseURL: this._domain_search_base_url,
       fields: { domain_column, has_header_row: Boolean(has_header_row) },
     });
   }
 
   async getDomainSearchFileStatus(fileId) {
-    return this._getStatusUtil(fileId, "/domain-search/filestatus", { bulkRoot: true });
+    return this._getStatusUtil(fileId, "/filestatus", {
+      bulkRoot: true,
+      baseURL: this._domain_search_base_url,
+    });
   }
 
   async getDomainSearchFile(fileId) {
-    return this._getFileUtil(fileId, "/domain-search/getfile", false, null, { bulkRoot: true });
+    return this._getFileUtil(fileId, "/getfile", false, null, {
+      bulkRoot: true,
+      baseURL: this._domain_search_base_url,
+    });
   }
 
   async deleteDomainSearchFile(fileId) {
-    return this._deleteFileUtil(fileId, "/domain-search/deletefile", false, { bulkRoot: true });
+    return this._deleteFileUtil(fileId, "/deletefile", false, {
+      bulkRoot: true,
+      baseURL: this._domain_search_base_url,
+    });
   }
 
   // LIST EVALUATOR (bulkapi.zerobounce.net/v2/listevaluator/)
@@ -1144,88 +1191,43 @@ export class ZeroBounceSDK {
     });
   }
 
-  async validateS3file({
-    file_name,
-    has_header_row,
-    remove_duplicates,
-    email_address_column = null,
-    return_url = false,
-    first_name_column = false,
-    last_name_column = false,
-    gender_column = false,
-    ip_address_column = false,
-    remove_duplicate = null,
-    allowPhase2 = null,
-  }) {
-    if (!this._initialized) {
-      notInitialized();
-      return;
-    } else if (isMissing(file_name)) {
-      parameterIsMissing("file_name");
-      return;
-    }
-    const fields = { file_name };
-    if (has_header_row != null) fields.has_header_row = has_header_row;
-    if (remove_duplicates != null) fields.remove_duplicates = remove_duplicates;
-    if (remove_duplicate != null) fields.remove_duplicate = remove_duplicate;
-    if (email_address_column != null) fields.email_address_column = email_address_column;
-    if (return_url) fields.return_url = return_url;
-    if (first_name_column) fields.first_name_column = first_name_column;
-    if (last_name_column) fields.last_name_column = last_name_column;
-    if (gender_column) fields.gender_column = gender_column;
-    if (ip_address_column) fields.ip_address_column = ip_address_column;
-    if (allowPhase2 != null) fields.allow_phase_2 = String(allowPhase2);
-    return this._sendBulkRootFormPost("/validateS3file", fields);
-  }
-
-  async scoreS3file({
-    file_name,
-    has_header_row,
-    remove_duplicates,
-    email_address_column = null,
-    remove_duplicate = null,
-  }) {
-    if (!this._initialized) {
-      notInitialized();
-      return;
-    } else if (isMissing(file_name)) {
-      parameterIsMissing("file_name");
-      return;
-    }
-    const fields = { file_name };
-    if (has_header_row != null) fields.has_header_row = has_header_row;
-    if (remove_duplicates != null) fields.remove_duplicates = remove_duplicates;
-    if (remove_duplicate != null) fields.remove_duplicate = remove_duplicate;
-    if (email_address_column != null) fields.email_address_column = email_address_column;
-    return this._sendBulkRootFormPost("/scoreS3file", fields);
+  /** Validate a file in your Amazon S3 bucket. POST /validateS3file */
+  async validateS3file(options) {
+    return this._bulkRootFileJob("/validateS3file", options || {});
   }
 
-  async exportS3file({ file_id, export_bucket }) {
+  /** Score a file in your Amazon S3 bucket. POST /scoreS3file */
+  async scoreS3file(options) {
+    return this._bulkRootFileJob("/scoreS3file", options || {});
+  }
+
+  /**
+   * Export a validated or scored file back to Amazon S3. POST /exportS3file
+   *
+   * Without export_bucket the output bucket from your ZeroBounce settings is
+   * used, as exportSFTPfile does with export_path.
+   * */
+  async exportS3file({ file_id, export_bucket = null } = {}) {
     if (!this._initialized) {
       notInitialized();
       return;
-    } else if (isMissing(file_id)) {
+    }
+    if (isMissing(file_id)) {
       parameterIsMissing("file_id");
       return;
-    } else if (isMissing(export_bucket)) {
+    }
+    if (export_bucket != null && String(export_bucket).trim() === "") {
       parameterIsMissing("export_bucket");
       return;
     }
-    return this._sendBulkRootFormPost("/exportS3file", {
-      file_id,
-      export_bucket,
-    });
+    const fields = { file_id };
+    if (export_bucket != null) fields.export_bucket = export_bucket;
+    return this._sendBulkRootFormPost("/exportS3file", fields);
   }
 
 
   /**
-   * Shared shape for the documented S3 and SFTP file jobs on the bulkapi root.
-   * Only fields the caller set are sent; booleans go as the strings true/false.
-   *
-   * @param fileNameRequired - false for validateSFTPfile, whose file_name is optional
-   * */
-  /**
-   * One of the six documented S3 / SFTP file jobs on the bulkapi root.
+   * One of the eight documented S3 / SFTP file jobs on the bulkapi root.
    *
    * LIVE: `return_url` is required, although the docs mark it optional —
    * without it the API answers "Provided return URL is not permitted: None".
@@ -1233,6 +1235,9 @@ export class ZeroBounceSDK {
    * the docs also mark optional ("file_name: This field is required").
    * All three are checked here so no request goes out without them.
    *
+   * The documented set of fields is file_name, has_header_row,
+   * remove_duplicates and return_url, and nothing else goes out.
+   *
    * The documented success is {success, message} with no file ID.
    */
   async _bulkRootFileJob(path, { file_name, has_header_row, remove_duplicates, return_url }) {
@@ -1278,11 +1283,10 @@ export class ZeroBounceSDK {
   /**
    * Validate a file from your SFTP/FTP server. POST /validateSFTPfile
    *
-   * The docs list file_name as optional here; leave it out to use the input
-   * bucket configured in your settings.
+   * LIVE: file_name is required here too, although the docs mark it optional.
    * */
   async validateSFTPfile(options) {
-    return this._bulkRootFileJob("/validateSFTPfile", options || {}, false);
+    return this._bulkRootFileJob("/validateSFTPfile", options || {});
   }
 
   /** Score a file from your SFTP/FTP server. POST /scoreSFTPfile */
@@ -1514,7 +1518,7 @@ export class ZeroBounceSDK {
 
   /**
    * @param domain str - domain of the email address
-   * @param first_name str - first name
+   * @param first_name str or null - first name (optional)
    * @param middle_name str or null - middle name
    * @param last_name str or null - last name
    * */
@@ -1534,7 +1538,7 @@ export class ZeroBounceSDK {
 
   /**
    * @param company_name str - company name of the email address
-   * @param first_name str - first name
+   * @param first_name str or null - first name (optional)
    * @param middle_name str or null - middle name
    * @param last_name str or null - last name
    * */
@@ -1555,7 +1559,7 @@ export class ZeroBounceSDK {
   async _findEmail({
     domain = null,
     company_name = null,
-    first_name,
+    first_name = null,
     middle_name = null,
     last_name = null
   }) {
@@ -1566,15 +1570,14 @@ export class ZeroBounceSDK {
       parameterIsMissing("domain");
       parameterIsMissing("company_name");
       return;
-    } else if (isMissing(first_name)) {
-      parameterIsMissing("first_name");
-      return;
     }
 
+    // first_name is optional: /guessformat answers a domain-only request with
+    // the domain's format, so an unset name is left out rather than rejected.
     const params = {
       api_key: this._api_key,
-      first_name: first_name,
     };
+    if (!isMissing(first_name)) params.first_name = first_name;
     if (!isMissing(middle_name)) params.middle_name = middle_name;
     if (!isMissing(last_name)) params.last_name = last_name;
 
diff --git a/tests/offline-api.test.js b/tests/offline-api.test.js
index 34e8d54..fabb386 100644
--- a/tests/offline-api.test.js
+++ b/tests/offline-api.test.js
@@ -312,8 +312,8 @@ describe("offline API", () => {
       ["getScoringFile", () => sdk.getScoringFile(id), "GET", "bulkapi.zerobounce.net", "/v2/scoring/getfile"],
       ["deleteFile", () => sdk.deleteFile(id), "GET", "bulkapi.zerobounce.net", "/v2/deletefile"],
       ["deleteScoringFile", () => sdk.deleteScoringFile(id), "GET", "bulkapi.zerobounce.net", "/v2/scoring/deletefile"],
-      ["sendEmailFinderFile", () => sdk.sendEmailFinderFile({ file, domain_column: 1 }), "POST", "bulkapi.zerobounce.net", "/email-finder/sendfile"],
-      ["sendEmailFinderFileStream", () => sdk.sendEmailFinderFileStream(file, "emails.csv", { domain_column: 1 }), "POST", "bulkapi.zerobounce.net", "/email-finder/sendfile"],
+      ["sendEmailFinderFile", () => sdk.sendEmailFinderFile({ file, domain_column: 1, first_name_column: 2 }), "POST", "bulkapi.zerobounce.net", "/email-finder/sendfile"],
+      ["sendEmailFinderFileStream", () => sdk.sendEmailFinderFileStream(file, "emails.csv", { domain_column: 1, full_name_column: 2 }), "POST", "bulkapi.zerobounce.net", "/email-finder/sendfile"],
       ["getEmailFinderFileStatus", () => sdk.getEmailFinderFileStatus(id), "GET", "bulkapi.zerobounce.net", "/email-finder/filestatus"],
       ["getEmailFinderFile", () => sdk.getEmailFinderFile(id), "GET", "bulkapi.zerobounce.net", "/email-finder/getfile"],
       ["deleteEmailFinderFile", () => sdk.deleteEmailFinderFile(id), "GET", "bulkapi.zerobounce.net", "/email-finder/deletefile"],
@@ -514,11 +514,19 @@ describe("offline API", () => {
     expect(request.fields.first_name_column).toBeUndefined();
 
     fake.records.length = 0;
-    await sdk.sendEmailFinderFile({ file, domain_column: 2, has_header_row: false, first_name_column: 0 });
+    await sdk.sendEmailFinderFile({
+      file,
+      domain_column: 2,
+      has_header_row: false,
+      full_name_column: 3,
+      middle_name_column: 0,
+    });
     request = fake.only();
     expect(request.fields.has_header_row).toBe("false");
     expect(request.fields.domain_column).toBe("2");
+    expect(request.fields.full_name_column).toBe("3");
     expect(request.fields.first_name_column).toBeUndefined();
+    expect(request.fields.middle_name_column).toBeUndefined();
 
     fake.records.length = 0;
     await sdk.sendDomainSearchFile({ file, domain_column: 1, has_header_row: false });
@@ -539,27 +547,12 @@ describe("offline API", () => {
     expect(request.fields.last_name_column).toBe("3");
 
     fake.records.length = 0;
-    await sdk.sendEmailFinderFile({ file, domain_column: 0 });
+    await sdk.sendEmailFinderFile({ file, domain_column: 0, first_name_column: 1 });
     expect(fake.only().fields.domain_column).toBe("0");
 
     fake.records.length = 0;
     await sdk.sendListEvaluatorFile({ file, email_address_column: 0 });
     expect(fake.only().fields.email_address_column).toBe("0");
-    fake.records.length = 0;
-    await sdk.validateS3file({
-      file_name: "f.csv",
-      email_address_column: 0,
-      first_name_column: 0,
-      has_header_row: false,
-      remove_duplicate: false,
-    });
-    request = fake.only();
-    expect(request.fields.email_address_column).toBe("0");
-    expect(request.fields.first_name_column).toBeUndefined();
-    expect(request.fields.has_header_row).toBe("false");
-    expect(request.fields.remove_duplicate).toBe("false");
-    expect(request.fields.allow_phase_2).toBeUndefined();
-
   });
 
   it("sends getFile download_type and activity_data only when set, and not for scoring", async () => {
@@ -660,11 +653,23 @@ describe("offline API", () => {
     await expectRejected(sdk.sendFile({ email_address_column: 1 }));
     await expectRejected(sdk.sendFile({ file }));
     await expectRejected(sdk.findEmailByDomain({ first_name: "Ada" }));
-    await expectRejected(sdk.findEmailByDomain({ domain: "example.com" }));
+    await expectRejected(sdk.findEmailFormatByDomain({ domain: "" }));
     await expectRejected(sdk.addFilter({ rule: "", target: "domain", value: "spam.com" }));
     await expectRejected(sdk.getFile(""));
-    await expectRejected(sdk.exportS3file({ file_id: "id" }));
+    await expectRejected(sdk.exportS3file({}));
+    await expectRejected(sdk.exportS3file({ file_id: "fid", export_bucket: "  " }));
     await expectRejected(sdk.emailFinderS3file({ has_header_row: true }));
+    await expectRejected(sdk.validateS3file({ file_name: "f.csv", has_header_row: true }));
+    await expectRejected(sdk.scoreS3file({ file_name: "f.csv", has_header_row: true }));
+    await expectRejected(
+      sdk.sendEmailFinderFile({ file, domain_column: 1 })
+    );
+    await expectRejected(
+      sdk.sendEmailFinderFile({ file, domain_column: 1, first_name_column: 0 })
+    );
+    await expectRejected(
+      sdk.sendEmailFinderFileStream(file, "emails.csv", { domain_column: 1 })
+    );
     await expectRejected(sdk.scoreSFTPfile({ file_name: "  ", has_header_row: true }));
     await expectRejected(sdk.domainSearchSFTPfile({ file_name: "f.csv" }));
     // LIVE: return_url is required even though the docs mark it optional.
@@ -917,6 +922,254 @@ describe("offline API", () => {
     await expect(csvSdk.getFile("file-1")).resolves.toBe("result.csv");
   });
 
+  it("sends validateBatch as JSON with the JSON content type", async () => {
+    const sdk = client("parity-key");
+    const batch = [{ email_address: "a@example.com", ip_address: "1.1.1.1" }];
+    const result = await sdk.validateBatch(batch, { timeout: 30, verifyPlus: true });
+
+    const request = fake.only();
+    expect(request.method).toBe("POST");
+    expect(request.url).toBe("https://api.zerobounce.net/v2/validatebatch");
+    // The key travels in the JSON body, not the query string.
+    expect(request.query).toEqual({});
+    expect(request.headers["Content-Type"]).toBe("application/json");
+    expect(request.json).toEqual({
+      api_key: "parity-key",
+      email_batch: batch,
+      // LIVE: timeout is a JSON string; the flags stay JSON booleans.
+      timeout: "30",
+      verify_plus: true,
+    });
+    expect(result.email_batch[0].status).toBe("valid");
+  });
+
+  it("finds an email without first_name and still sends it when given", async () => {
+    const sdk = client("parity-key");
+    await sdk.findEmailByDomain({ domain: "example.com" });
+    let request = fake.only();
+    expect(request.method).toBe("GET");
+    expect(request.url).toBe(
+      "https://api.zerobounce.net/v2/guessformat?api_key=parity-key&domain=example.com"
+    );
+    expect(request.query.first_name).toBeUndefined();
+
+    fake.records.length = 0;
+    await sdk.findEmailByCompanyName({ company_name: "Ada Inc" });
+    request = fake.only();
+    expect(request.url).toBe(
+      "https://api.zerobounce.net/v2/guessformat?api_key=parity-key&company_name=Ada+Inc"
+    );
+    expect(request.query.first_name).toBeUndefined();
+
+    fake.records.length = 0;
+    const result = await sdk.findEmailByDomain({
+      domain: "example.com",
+      first_name: "Ada",
+      last_name: "Lovelace",
+    });
+    request = fake.only();
+    expect(request.query).toEqual({
+      api_key: "parity-key",
+      first_name: "Ada",
+      last_name: "Lovelace",
+      domain: "example.com",
+    });
+    expect(result.email).toBe("ada@example.com");
+
+    // The domain is still required, and the domain-search family is untouched.
+    await expectRejected(sdk.findEmailByDomain({ first_name: "Ada" }));
+    await expectRejected(sdk.findEmailByCompanyName({ first_name: "Ada" }));
+  });
+
+  it("requires a first_name_column or full_name_column for the bulk email finder", async () => {
+    const sdk = client("parity-key");
+    const missing = await expectRejected(sdk.sendEmailFinderFile({ file, domain_column: 1 }));
+    expect(missing.message).toBe(
+      "ZeroBounce: first_name_column parameter is missing. Send first_name_column or full_name_column."
+    );
+    // 0 and false mean "leave this column out", so neither counts as given.
+    await expectRejected(
+      sdk.sendEmailFinderFile({ file, domain_column: 1, first_name_column: 0 })
+    );
+    await expectRejected(
+      sdk.sendEmailFinderFile({ file, domain_column: 1, full_name_column: false })
+    );
+    await expectRejected(
+      sdk.sendEmailFinderFileStream(file, "emails.csv", { domain_column: 1 })
+    );
+    expect(fake.records).toHaveLength(0);
+
+    await sdk.sendEmailFinderFile({ file, domain_column: 1, first_name_column: 2 });
+    let request = fake.only();
+    expect(request.method).toBe("POST");
+    expect(request.url).toBe("https://bulkapi.zerobounce.net/email-finder/sendfile");
+    expect(request.fields.first_name_column).toBe("2");
+    expect(request.fields.api_key).toBe("parity-key");
+
+    fake.records.length = 0;
+    await sdk.sendEmailFinderFileStream(file, "emails.csv", {
+      domain_column: 1,
+      full_name_column: 3,
+    });
+    request = fake.only();
+    expect(request.url).toBe("https://bulkapi.zerobounce.net/email-finder/sendfile");
+    expect(request.fields.full_name_column).toBe("3");
+    expect(request.fields.first_name_column).toBeUndefined();
+  });
+
+  it("honours the emailFinderBaseURL and domainSearchBaseURL overrides", async () => {
+    const sdk = new ZeroBounceSDK();
+    sdk.init("parity-key", ZeroBounceSDK.ApiURL.DEFAULT_API_URL, {
+      emailFinderBaseURL: "https://finder.example.com/email-finder",
+      domainSearchBaseURL: "https://search.example.com/domain-search",
+    });
+
+    const calls = [
+      [() => sdk.sendEmailFinderFile({ file, domain_column: 1, first_name_column: 2 }), "POST", "https://finder.example.com/email-finder/sendfile"],
+      [() => sdk.sendEmailFinderFileStream(file, "emails.csv", { domain_column: 1, first_name_column: 2 }), "POST", "https://finder.example.com/email-finder/sendfile"],
+      [() => sdk.getEmailFinderFileStatus("file-1"), "GET", "https://finder.example.com/email-finder/filestatus?api_key=parity-key&file_id=file-1"],
+      [() => sdk.getEmailFinderFile("file-1"), "GET", "https://finder.example.com/email-finder/getfile?api_key=parity-key&file_id=file-1"],
+      [() => sdk.deleteEmailFinderFile("file-1"), "GET", "https://finder.example.com/email-finder/deletefile?api_key=parity-key&file_id=file-1"],
+      [() => sdk.sendDomainSearchFile({ file, domain_column: 1 }), "POST", "https://search.example.com/domain-search/sendfile"],
+      [() => sdk.sendDomainSearchFileStream(file, "emails.csv", { domain_column: 1 }), "POST", "https://search.example.com/domain-search/sendfile"],
+      [() => sdk.getDomainSearchFileStatus("file-1"), "GET", "https://search.example.com/domain-search/filestatus?api_key=parity-key&file_id=file-1"],
+      [() => sdk.getDomainSearchFile("file-1"), "GET", "https://search.example.com/domain-search/getfile?api_key=parity-key&file_id=file-1"],
+      [() => sdk.deleteDomainSearchFile("file-1"), "GET", "https://search.example.com/domain-search/deletefile?api_key=parity-key&file_id=file-1"],
+    ];
+    for (const [run, method, url] of calls) {
+      fake.records.length = 0;
+      await run();
+      expect({ method: fake.only().method, url: fake.only().url }).toEqual({ method, url });
+      expect(fake.only().apiKey).toBe("parity-key");
+    }
+
+    // An override is still checked, and a default client keeps the bulk host.
+    const bare = new ZeroBounceSDK();
+    expect(() =>
+      bare.init("parity-key", ZeroBounceSDK.ApiURL.DEFAULT_API_URL, {
+        emailFinderBaseURL: "http://finder.example.com",
+      })
+    ).toThrow(/emailFinderBaseURL must be an https/);
+    expect(() =>
+      bare.init("parity-key", ZeroBounceSDK.ApiURL.DEFAULT_API_URL, {
+        domainSearchBaseURL: "http://search.example.com",
+      })
+    ).toThrow(/domainSearchBaseURL must be an https/);
+
+    fake.records.length = 0;
+    await client("parity-key").getEmailFinderFileStatus("file-1");
+    expect(fake.only().url).toBe(
+      "https://bulkapi.zerobounce.net/email-finder/filestatus?api_key=parity-key&file_id=file-1"
+    );
+  });
+
+  it("sends exactly the documented fields for the S3 and SFTP file jobs", async () => {
+    const sdk = client("parity-key");
+    const jobs = [
+      ["validateS3file", (options) => sdk.validateS3file(options), "/validateS3file"],
+      ["scoreS3file", (options) => sdk.scoreS3file(options), "/scoreS3file"],
+      ["emailFinderS3file", (options) => sdk.emailFinderS3file(options), "/emailFinderS3file"],
+      ["domainSearchS3file", (options) => sdk.domainSearchS3file(options), "/domainSearchS3file"],
+      ["validateSFTPfile", (options) => sdk.validateSFTPfile(options), "/validateSFTPfile"],
+      ["scoreSFTPfile", (options) => sdk.scoreSFTPfile(options), "/scoreSFTPfile"],
+      ["emailFinderSFTPfile", (options) => sdk.emailFinderSFTPfile(options), "/emailFinderSFTPfile"],
+      ["domainSearchSFTPfile", (options) => sdk.domainSearchSFTPfile(options), "/domainSearchSFTPfile"],
+    ];
+
+    for (const [name, run, path] of jobs) {
+      fake.records.length = 0;
+      const result = await run({
+        file_name: "emails/list.csv",
+        has_header_row: true,
+        remove_duplicates: false,
+        return_url: "https://example.com/done",
+        // Undocumented extras a caller may still pass: none may go out.
+        email_address_column: 1,
+        first_name_column: 2,
+        last_name_column: 3,
+        gender_column: 4,
+        ip_address_column: 5,
+        remove_duplicate: true,
+        allowPhase2: true,
+      });
+      const request = fake.only();
+      expect({ name, method: request.method, url: request.url }).toEqual({
+        name,
+        method: "POST",
+        url: `https://bulkapi.zerobounce.net${path}`,
+      });
+      expect(request.query).toEqual({});
+      expect(request.body).toEqual({
+        api_key: "parity-key",
+        file_name: "emails/list.csv",
+        has_header_row: "true",
+        remove_duplicates: "false",
+        return_url: "https://example.com/done",
+      });
+      expect(result.success).toBe(true);
+    }
+
+    // LIVE: file_name, has_header_row and return_url are all required.
+    fake.records.length = 0;
+    for (const [, run] of jobs) {
+      await expectRejected(run({ has_header_row: true, return_url: "https://example.com/done" }));
+      await expectRejected(run({ file_name: "f.csv", return_url: "https://example.com/done" }));
+      const noUrl = await expectRejected(run({ file_name: "f.csv", has_header_row: true }));
+      expect(noUrl.message).toBe(
+        "ZeroBounce: return_url parameter is missing. The API rejects a job without it."
+      );
+    }
+    expect(fake.records).toHaveLength(0);
+  });
+
+  it("makes export_bucket optional on exportS3file, as export_path is on exportSFTPfile", async () => {
+    const sdk = client("parity-key");
+    await sdk.exportS3file({ file_id: "job-1" });
+    let request = fake.only();
+    expect(request.method).toBe("POST");
+    expect(request.url).toBe("https://bulkapi.zerobounce.net/exportS3file");
+    expect(request.body).toEqual({ api_key: "parity-key", file_id: "job-1" });
+
+    fake.records.length = 0;
+    const result = await sdk.exportS3file({ file_id: "job-1", export_bucket: "my-bucket" });
+    request = fake.only();
+    expect(request.body).toEqual({
+      api_key: "parity-key",
+      file_id: "job-1",
+      export_bucket: "my-bucket",
+    });
+    expect(result.success).toBe(true);
+
+    fake.records.length = 0;
+    await expectRejected(sdk.exportS3file({}));
+    await expectRejected(sdk.exportS3file({ file_id: "job-1", export_bucket: "   " }));
+    expect(fake.records).toHaveLength(0);
+  });
+
+  it("reports the API's own error body for a rejected S3 job", async () => {
+    const sdk = client("parity-key");
+    jest.spyOn(global, "fetch").mockImplementationOnce(() =>
+      Promise.resolve({
+        ok: false,
+        status: 400,
+        headers: { get: () => "application/json" },
+        text: () =>
+          Promise.resolve(
+            JSON.stringify({ error_message: "Provided return URL is not permitted: None" })
+          ),
+      })
+    );
+    const error = await expectRejected(
+      sdk.validateS3file({
+        file_name: "emails/list.csv",
+        has_header_row: true,
+        return_url: "https://example.com/done",
+      })
+    );
+    expect(error.message).toBe("Provided return URL is not permitted: None");
+    expect(error.statusCode).toBe(400);
+  });
+
   it("keeps API keys isolated across concurrent clients", async () => {
     const clients = Array.from({ length: 12 }, (_, index) => {
       const key = `client-${String(index).padStart(4, "0")}-secret`;
diff --git a/tests/ts-consumer.ts b/tests/ts-consumer.ts
index fc1da64..26c1f3c 100644
--- a/tests/ts-consumer.ts
+++ b/tests/ts-consumer.ts
@@ -33,6 +33,13 @@ import ZeroBounceSDK, {
   type EmailFinderResponse,
   type DomainFormatResponse,
   type SendScoringFileResponse,
+  type SendEmailFinderFileOptions,
+  type SendEmailFinderFileStreamOptions,
+  type BulkRootFileJobOptions,
+  type ValidateS3FileOptions,
+  type ScoreS3FileOptions,
+  type ExportS3FileOptions,
+  type S3BulkJobResponse,
 } from "@zerobounce/zero-bounce-sdk";
 
 // --- Class and static members ---
@@ -77,10 +84,42 @@ const findByCompanyOpts: FindEmailByCompanyNameOptions = {
   first_name: "Jane",
 };
 
+// first_name is optional on both: /guessformat answers with the format.
+const findByDomainNoName: FindEmailByDomainOptions = { domain: "example.com" };
+const findByCompanyNoName: FindEmailByCompanyNameOptions = { company_name: "Acme Inc" };
+
+// A bulk email finder file takes first_name_column or full_name_column.
+const finderFileOpts: SendEmailFinderFileStreamOptions = {
+  domain_column: 1,
+  first_name_column: 2,
+};
+const finderFullNameOpts: SendEmailFinderFileStreamOptions = {
+  domain_column: 1,
+  full_name_column: 2,
+};
+
+// The S3 / SFTP jobs all take the same documented set of fields.
+const s3JobOpts: BulkRootFileJobOptions = {
+  file_name: "emails/list.csv",
+  has_header_row: true,
+  remove_duplicates: false,
+  return_url: "https://example.com/done",
+};
+const validateS3Opts: ValidateS3FileOptions = s3JobOpts;
+const scoreS3Opts: ScoreS3FileOptions = s3JobOpts;
+const exportS3Opts: ExportS3FileOptions = { file_id: "job-1" };
+
 // --- Method signatures (types only; we don't call the API) ---
 const zb: ZeroBounceSDK = new ZeroBounceSDK();
 
 zb.init("fake-key", ZeroBounceSDK.ApiURL.DEFAULT_API_URL);
+// Every overridable base URL, including the finder and domain-search hosts.
+zb.init("fake-key", ZeroBounceSDK.ApiURL.DEFAULT_API_URL, {
+  listEvaluatorBaseURL: "https://bulkapi.zerobounce.net/v2/listevaluator",
+  inboxPlacementBaseURL: "https://bulkapi.zerobounce.net/api/ipt",
+  emailFinderBaseURL: "https://bulkapi.zerobounce.net/email-finder",
+  domainSearchBaseURL: "https://bulkapi.zerobounce.net/domain-search",
+});
 
 // Return types are Promise<...>; we only check they're assignable
 const creditsPromise: Promise<GetCreditsResponse | undefined> = zb.getCredits();
@@ -208,6 +247,23 @@ zb.sendFileStream(blob, "emails.csv", sendFileStreamOpts);
 zb.sendScoringFileStream(blob, "scoring.csv");
 zb.sendScoringFileStream(blob, "scoring.csv", sendScoringStreamOpts);
 
+const finderFileSendOpts: SendEmailFinderFileOptions = {
+  file: blob as unknown as File,
+  domain_column: 1,
+  full_name_column: 2,
+};
+zb.sendEmailFinderFile(finderFileSendOpts);
+zb.sendEmailFinderFileStream(blob, "finder.csv", finderFileOpts);
+
+const validateS3Promise: Promise<S3BulkJobResponse | undefined> =
+  zb.validateS3file(validateS3Opts);
+const scoreS3Promise: Promise<S3BulkJobResponse | undefined> = zb.scoreS3file(scoreS3Opts);
+const exportS3Promise: Promise<S3BulkJobResponse | undefined> = zb.exportS3file(exportS3Opts);
+const validateSFTPPromise: Promise<S3BulkJobResponse | undefined> =
+  zb.validateSFTPfile(s3JobOpts);
+zb.findEmailByDomain(findByDomainNoName);
+zb.findEmailByCompanyName(findByCompanyNoName);
+
 // Ensure types are used (avoid unused variable warnings in strict mode)
 function assertTypes(): void {
   void creditsPromise;
@@ -250,6 +306,12 @@ function assertTypes(): void {
   void statusValid;
   void statusInvalid;
   void subStatus;
+  void finderFullNameOpts;
+  void finderFileSendOpts;
+  void validateS3Promise;
+  void scoreS3Promise;
+  void exportS3Promise;
+  void validateSFTPPromise;
 }
 
 assertTypes();
diff --git a/tests/warmup-offline.test.js b/tests/warmup-offline.test.js
index 04ae1f9..ac3b71b 100644
--- a/tests/warmup-offline.test.js
+++ b/tests/warmup-offline.test.js
@@ -199,6 +199,17 @@ describe("Warmup API client", () => {
       managed_sending: { timezone_offset: 2, warmup_start_date: "2026-02-01" },
     });
 
+    // A zb_managed account takes no engagement rule: say so rather than drop it.
+    fake.records.length = 0;
+    expect(() =>
+      c.addSendingAccount({
+        fromAddress: "sender@example.com",
+        onboardingModel: "zb_managed",
+        engagementRuleId: 2,
+      })
+    ).toThrow("ZeroBounce: engagement_rule_id is for self_managed.");
+    expect(fake.records).toHaveLength(0);
+
     fake.records.length = 0;
     await c.updateSendingAccount({
       fromAddress: "sender@example.com",
@@ -224,6 +235,8 @@ describe("Warmup API client", () => {
       () => c.addSendingAccount({ fromAddress: "a@example.com", onboardingModel: "nope" }),
       () => c.addSendingAccount({ fromAddress: "a@example.com", onboardingModel: "self_managed" }),
       () => c.addSendingAccount({ fromAddress: "a@example.com", onboardingModel: "self_managed", engagementRuleId: 9 }),
+      // zb_managed has no engagement_rule_id: it is rejected, not dropped.
+      () => c.addSendingAccount({ fromAddress: "a@example.com", onboardingModel: "zb_managed", engagementRuleId: 1 }),
       () => c.updateSendingAccount({ fromAddress: "a@example.com", engagementRuleId: 1, statusId: 1 }),
       () => c.setEngagementRule("a@example.com", 7),
       () => c.createCustomEngagement({ cFrom: "a@example.com", replyPct: 1, importantPct: 10, clickPct: 5 }),
diff --git a/tests/zero-bounce.test.js b/tests/zero-bounce.test.js
index bfcf388..c18ebe6 100644
--- a/tests/zero-bounce.test.js
+++ b/tests/zero-bounce.test.js
@@ -1186,7 +1186,7 @@ describe("ZeroBounceSDK", () => {
       const fetch = jest.spyOn(global, "fetch").mockImplementationOnce(() =>
         jsonOk({ success: true, file_id: "fid" })
       );
-      await zeroBounceSDK.sendEmailFinderFile({ file, domain_column: 1 });
+      await zeroBounceSDK.sendEmailFinderFile({ file, domain_column: 1, first_name_column: 2 });
       expect(String(fetch.mock.calls[0][0])).toContain(
         "https://bulkapi.zerobounce.net/email-finder/sendfile"
       );
@@ -1270,10 +1270,19 @@ describe("ZeroBounceSDK", () => {
         file_name: "emails/list.csv",
         has_header_row: true,
         remove_duplicates: true,
+        return_url: "https://example.com/done",
       });
       expect(String(fetch.mock.calls[0][0])).toBe(
         "https://bulkapi.zerobounce.net/validateS3file"
       );
+      const body = fetch.mock.calls[0][1].body;
+      expect(Object.fromEntries(body.entries())).toEqual({
+        api_key: "valid-api-key",
+        file_name: "emails/list.csv",
+        has_header_row: "true",
+        remove_duplicates: "true",
+        return_url: "https://example.com/done",
+      });
     });
 
     it("exportS3file posts file_id and export_bucket", async () => {
diff --git a/zeroBounceSDK.d.ts b/zeroBounceSDK.d.ts
index acd6583..e77dade 100644
--- a/zeroBounceSDK.d.ts
+++ b/zeroBounceSDK.d.ts
@@ -361,7 +361,12 @@ export interface SendScoringFileStreamOptions {
   remove_duplicate?: boolean;
 }
 
-/** Options for bulk email finder sendfile. */
+/**
+ * Options for bulk email finder sendfile.
+ *
+ * Send `first_name_column` or `full_name_column`; `0` and `false` mean
+ * "leave this column out" and so do not count as given.
+ */
 export interface SendEmailFinderFileOptions {
   file: File;
   domain_column: number;
@@ -372,6 +377,7 @@ export interface SendEmailFinderFileOptions {
   has_header_row?: boolean;
 }
 
+/** As SendEmailFinderFileOptions, for a stream or Blob. */
 export interface SendEmailFinderFileStreamOptions {
   domain_column: number;
   first_name_column?: number | false;
@@ -446,33 +452,16 @@ export interface ListFiltersOptions {
   method?: "GET" | "POST";
 }
 
-export interface ValidateS3FileOptions {
-  file_name: string;
-  has_header_row?: boolean;
-  /** Postman field name for duplicate removal. */
-  remove_duplicates?: boolean;
-  /** Alternate field name used by some bulk endpoints. */
-  remove_duplicate?: boolean;
-  email_address_column?: number;
-  return_url?: string | false;
-  first_name_column?: number | false;
-  last_name_column?: number | false;
-  gender_column?: number | false;
-  ip_address_column?: number | false;
-  allowPhase2?: boolean | null;
-}
+/** Options for validateS3file: the shared S3 / SFTP job fields. */
+export interface ValidateS3FileOptions extends BulkRootFileJobOptions {}
 
-export interface ScoreS3FileOptions {
-  file_name: string;
-  has_header_row?: boolean;
-  remove_duplicates?: boolean;
-  remove_duplicate?: boolean;
-  email_address_column?: number;
-}
+/** Options for scoreS3file: the shared S3 / SFTP job fields. */
+export interface ScoreS3FileOptions extends BulkRootFileJobOptions {}
 
 export interface ExportS3FileOptions {
   file_id: string;
-  export_bucket: string;
+  /** Defaults to the export bucket in your ZeroBounce settings. */
+  export_bucket?: string;
 }
 
 /** Single entry from GET /listS3files. */
@@ -523,13 +512,19 @@ export interface ListInboxPlacementTestsOptions {
   pageSize?: number;
 }
 
-/** Shared options for the documented S3 and SFTP file jobs. */
+/**
+ * Shared options for the documented S3 and SFTP file jobs.
+ *
+ * The live API requires `file_name` and `return_url` on every one of them,
+ * including validateSFTPfile, although the docs mark them optional.
+ */
 export interface BulkRootFileJobOptions {
-  /** Full path as returned by listS3files. Optional only for validateSFTPfile. */
-  file_name?: string;
+  /** Full path as returned by listS3files. */
+  file_name: string;
   has_header_row: boolean;
   remove_duplicates?: boolean;
-  return_url?: string;
+  /** The API rejects a job without it. */
+  return_url: string;
 }
 
 /** Options for exportSFTPfile. */
@@ -542,7 +537,8 @@ export interface ExportSFTPFileOptions {
 /** Options for findEmailByDomain / Email Finder. */
 export interface FindEmailByDomainOptions {
   domain: string;
-  first_name: string;
+  /** Optional: without it the API answers with the domain's format. */
+  first_name?: string | null;
   middle_name?: string | null;
   last_name?: string | null;
 }
@@ -550,7 +546,8 @@ export interface FindEmailByDomainOptions {
 /** Options for findEmailByCompanyName / Email Finder. */
 export interface FindEmailByCompanyNameOptions {
   company_name: string;
-  first_name: string;
+  /** Optional: without it the API answers with the company's format. */
+  first_name?: string | null;
   middle_name?: string | null;
   last_name?: string | null;
 }
@@ -592,6 +589,10 @@ export class ZeroBounceSDK {
       listEvaluatorBaseURL?: string;
       /** Defaults to https://bulkapi.zerobounce.net/api/ipt */
       inboxPlacementBaseURL?: string;
+      /** Defaults to https://bulkapi.zerobounce.net/email-finder */
+      emailFinderBaseURL?: string;
+      /** Defaults to https://bulkapi.zerobounce.net/domain-search */
+      domainSearchBaseURL?: string;
     } | null
   ): void;
 
@@ -832,9 +833,9 @@ export class ZeroBounceSDK {
     options: BulkRootFileJobOptions
   ): Promise<S3BulkJobResponse | undefined>;
 
-  /** file_name is optional here; omit it to use the configured input bucket. */
+  /** LIVE: file_name is required here too, although the docs mark it optional. */
   validateSFTPfile(
-    options: BulkRootFileJobOptions | { has_header_row: boolean; remove_duplicates?: boolean; return_url?: string }
+    options: BulkRootFileJobOptions
   ): Promise<S3BulkJobResponse | undefined>;
 
   scoreSFTPfile(
@@ -957,7 +958,7 @@ export class ZeroBounceWarmup {
   addSendingAccount(options: {
     fromAddress: string;
     onboardingModel: WarmupOnboardingModel;
-    /** 0 to 4. Required for self_managed. */
+    /** 0 to 4. Required for self_managed, and rejected for zb_managed. */
     engagementRuleId?: number | null;
     ignoreConflict?: boolean | null;
     emailContent?: WarmupEmailContent | null;