P2P Protocol — On-Chain + Off-Chain Backend

A fully on-chain orderbook DEX on Solana. Every order is a PDA, every fill is atomic, every state change emits a structured binary event. This repo contains the on-chain program, the indexer service, and the REST API service.

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Repository Structure

.
├── programs/
│   └── p2p-protocol/       On-chain Solana program (Pinocchio 0.11, no Anchor)
├── services/
│   ├── api/                Axum REST API — serves indexed data over HTTP
│   ├── indexer/            Real-time indexer — listens to Solana logs, writes to PostgreSQL
│   └── migrations/
│       └── 001_initial.sql PostgreSQL schema
├── Cargo.toml              Cargo workspace root
└── Cargo.lock

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On-Chain Program

• Program ID: HazZUxenwxgxDumK5rt89mhXfffnVpA7Nyvx87kMts18
• Network: Solana Devnet
• Runtime: SBPF via Pinocchio 0.11 — zero Anchor overhead, under 5,000 CU per instruction

Instructions

Instruction	Description
create_market	Initialise a new market with base/quote mints, tick size, lot size, fee bps
place_order	Place a Limit, IOC, FOK, or Post-Only order — stored as a PDA
fill_order	Atomically match maker and taker, release escrowed tokens
cancel_order	Cancel an open order and return escrowed tokens to owner

Events

Every instruction emits a structured binary event via sol_log_data:

Discriminator	Event
1	OrderPlaced
2	OrderFilled
3	OrderCancelled
4	OrderExpired
5	MarketCreated

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Services

Both services are part of the same Cargo workspace and share the root Cargo.toml.

Indexer (services/indexer)

Connects to Solana via WebSocket (logsSubscribe), decodes binary events from program log data, and writes them to PostgreSQL in real time. On startup it also runs getProgramAccounts to back-fill any markets and orders that exist on-chain before the indexer started.

Flow:

Solana Devnet WS → logsSubscribe → decode binary event → upsert to PostgreSQL
                                                        ↑
                              getProgramAccounts (on startup, back-fill)

Environment variables:

Variable	Default	Description
DATABASE_URL	required	PostgreSQL connection string
SOLANA_RPC_URL	https://api.devnet.solana.com	Solana HTTP RPC endpoint
SOLANA_WS_URL	wss://api.devnet.solana.com	Solana WebSocket endpoint
PROGRAM_ID	HazZUxen...	Program ID to subscribe to

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API (services/api)

Stateless Axum HTTP server that reads from PostgreSQL and exposes indexed data as JSON. Fully CORS-enabled.

Environment variables:

Variable	Default	Description
DATABASE_URL	required	PostgreSQL connection string
API_PORT	3001	Port to listen on

Endpoints:

Method	Path	Description
GET	/health	Health check
GET	/stats	Protocol-wide stats (markets, open orders, total fills)
GET	/markets	List all indexed markets
GET	/markets/:address	Market detail + full order book (bids + asks)
GET	/markets/:address/orders	All orders for a market
GET	/markets/:address/events	Events for a market
GET	/orders/:address	Single order by address
GET	/events	Global event feed (supports ?limit=)

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Database Schema

PostgreSQL — four tables, auto-migrated by the indexer on startup.

markets   address (PK), base_mint, quote_mint, vaults, tick_size, lot_size, fee_bps
orders    address (PK), market (FK), owner, price, qty, filled_qty, side, status
fills     id, signature, market, order_addr, maker, taker, fill_price, fill_qty
events    id, signature, market, event_type, data (JSONB), slot, timestamp

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Running Locally

Prerequisites: Rust 1.75+, PostgreSQL (or a NeonDB connection string)

1. Set environment variables

cp services/.env.example services/.env
# Edit services/.env with your DATABASE_URL and RPC URLs

2. Run the indexer

cargo run -p p2p-indexer

Migrations run automatically on first start.

3. Run the API

cargo run -p p2p-api
# Listening on http://0.0.0.0:3001

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Deployment (Railway)

Both services have Dockerfiles that build from the workspace root. The Docker build context must be the repo root (not a subdirectory) because of the Cargo workspace.

API service

• Dockerfile: services/api/Dockerfile
• Root directory: / (repo root)
• Required env vars: DATABASE_URL, API_PORT
• Expose a public domain for the HTTP endpoint

Indexer service

• Dockerfile: services/indexer/Dockerfile
• Root directory: / (repo root)
• Required env vars: DATABASE_URL, SOLANA_RPC_URL, SOLANA_WS_URL, PROGRAM_ID
• No public domain needed — outbound only

Local Docker build (from repo root):

docker build -f services/api/Dockerfile     -t p2p-api     .
docker build -f services/indexer/Dockerfile -t p2p-indexer .

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Tech Stack

Layer	Technology
On-chain	Rust, Pinocchio 0.11, SBPF
Indexer	Rust, Tokio, tokio-tungstenite, SQLx
API	Rust, Axum 0.8, SQLx, tower-http
Database	PostgreSQL (NeonDB)
Network	Solana Devnet