diff --git a/.github/workflows/build_docs.yaml b/.github/workflows/build_docs.yaml
index 2b6f5c3..e0cf2f9 100644
--- a/.github/workflows/build_docs.yaml
+++ b/.github/workflows/build_docs.yaml
@@ -16,10 +16,10 @@ jobs:
   build-docs:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v2
+    - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
 
     - name: "Set up Python 3.10"
-      uses: actions/setup-python@v3
+      uses: actions/setup-python@3542bca2639a428e1796aaa6a2ffef0c0f575566 # v3
       with:
         python-version: "3.10"
 
@@ -36,7 +36,7 @@ jobs:
           cp -r docs/_extras/* docs/_build/html/
 
     - name: Deploy to GitHub Pages
-      uses: peaceiris/actions-gh-pages@v4
+      uses: peaceiris/actions-gh-pages@84c30a85c19949d7eee79c4ff27748b70285e453 # v4
       with:
         github_token: ${{ secrets.GITHUB_TOKEN }}
         publish_dir: docs/_build/html
diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 58f9780..dd5cea4 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -17,10 +17,10 @@ jobs:
     runs-on: ${{ matrix.os }}
     name: Test with Python ${{ matrix.version }} (${{ matrix.os }})
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
 
       - name: Set up Python ${{ matrix.version }}
-        uses: actions/setup-python@v5
+        uses: actions/setup-python@a26af69be951a213d495a4c3e4e4022e16d87065 # v5
         with:
           python-version: ${{ matrix.version }}
 
diff --git a/.github/workflows/formatting.yaml b/.github/workflows/formatting.yaml
index f40f647..53147d0 100644
--- a/.github/workflows/formatting.yaml
+++ b/.github/workflows/formatting.yaml
@@ -9,9 +9,9 @@ jobs:
   pre-commit:
     runs-on: ubuntu-latest
     steps:
-    - uses: actions/checkout@v3
-    - uses: actions/setup-python@v3
+    - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3
+    - uses: actions/setup-python@3542bca2639a428e1796aaa6a2ffef0c0f575566 # v3
       with:
         python-version: "3.10"
 
-    - uses: pre-commit/action@v3.0.0
+    - uses: pre-commit/action@646c83fcd040023954eafda54b4db0192ce70507 # v3.0.0