diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6ec5ea5..2470b07 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -30,7 +30,7 @@ jobs:
     name: warnings + test
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
 
       # prost-build does not vendor protoc; without it the proto crate fails with NotFound.
       - name: Install protoc
@@ -40,15 +40,15 @@ jobs:
       # `rustup show` installs exactly that, so the pin has one home.
       - name: Install the pinned Rust toolchain
         run: rustup show && cargo --version && git --version
-      - uses: Swatinem/rust-cache@v2
-      - uses: taiki-e/install-action@v2
+      - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+      - uses: taiki-e/install-action@e67fa11c4b9316fa714ddf0abed07a0c3143b95b # v2.87.4
         with:
           tool: just
 
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@b906affcce14559ad1aafd4ab0e942779e9f58b1 # v4.3.0
         with:
           version: 10
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
         with:
           node-version: 22
           cache: pnpm
@@ -68,19 +68,19 @@ jobs:
     name: e2e
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
       - name: Install protoc
         run: sudo apt-get update && sudo apt-get install -y protobuf-compiler
       - name: Install the pinned Rust toolchain
         run: rustup show && cargo --version && git --version
-      - uses: Swatinem/rust-cache@v2
-      - uses: taiki-e/install-action@v2
+      - uses: Swatinem/rust-cache@6323deb102c322ba6fcbdcafc7e3dddab59af2b6 # v2.9.2
+      - uses: taiki-e/install-action@e67fa11c4b9316fa714ddf0abed07a0c3143b95b # v2.87.4
         with:
           tool: just
-      - uses: pnpm/action-setup@v4
+      - uses: pnpm/action-setup@b906affcce14559ad1aafd4ab0e942779e9f58b1 # v4.3.0
         with:
           version: 10
-      - uses: actions/setup-node@v4
+      - uses: actions/setup-node@49933ea5288caeca8642d1e84afbd3f7d6820020 # v4.4.0
         with:
           node-version: 22
           cache: pnpm
diff --git a/.github/workflows/pages.yml b/.github/workflows/pages.yml
index 3867b70..6792142 100644
--- a/.github/workflows/pages.yml
+++ b/.github/workflows/pages.yml
@@ -24,11 +24,11 @@ jobs:
       url: ${{ steps.deployment.outputs.page_url }}
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v4
-      - uses: actions/configure-pages@v5
-      - uses: actions/upload-pages-artifact@v3
+      - uses: actions/checkout@11d5960a326750d5838078e36cf38b85af677262 # v4.4.0
+      - uses: actions/configure-pages@983d7736d9b0ae728b81ab479565c72886d7745b # v5.0.0
+      - uses: actions/upload-pages-artifact@56afc609e74202658d3ffba0e8f6dda462b719fa # v3.0.1
         with:
           path: site
       - name: Deploy to GitHub Pages
         id: deployment
-        uses: actions/deploy-pages@v4
+        uses: actions/deploy-pages@d6db90164ac5ed86f2b6aed7e0febac5b3c0c03e # v4.0.5