diff --git a/.github/workflows/CI_check_api_ref.yml b/.github/workflows/CI_check_api_ref.yml
index 89f2b690..aef38aa2 100644
--- a/.github/workflows/CI_check_api_ref.yml
+++ b/.github/workflows/CI_check_api_ref.yml
@@ -10,10 +10,10 @@ jobs:
   test-api-reference-build:
     runs-on: ubuntu-slim
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "3.13"
 
@@ -24,7 +24,7 @@ jobs:
         run: hatch run docs
 
       - name: Set up Node.js
-        uses: actions/setup-node@v6
+        uses: actions/setup-node@53b83947a5a98c8d113130e565377fae1a50d02f # v6.3.0
         with:
           node-version: "22"
 
diff --git a/.github/workflows/docusaurus_sync.yml b/.github/workflows/docusaurus_sync.yml
index ab09d852..7b52f532 100644
--- a/.github/workflows/docusaurus_sync.yml
+++ b/.github/workflows/docusaurus_sync.yml
@@ -20,10 +20,10 @@ jobs:
 
     steps:
       - name: Checkout this repo
-        uses: actions/checkout@v5
+        uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "${{ env.PYTHON_VERSION }}"
 
@@ -34,7 +34,7 @@ jobs:
         run: hatch run docs
 
       - name: Upload API reference artifact
-        uses: actions/upload-artifact@v7
+        uses: actions/upload-artifact@bbbca2ddaa5d8feaa63e36b76fdaad77386f024f # v7.0.0
         with:
           name: experimental-api-reference
           path: tmp_api_reference
@@ -49,19 +49,19 @@ jobs:
 
     steps:
       - name: Checkout Haystack repo
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
         with:
           repository: deepset-ai/haystack
           ref: main
           token: ${{ secrets.HAYSTACK_BOT_TOKEN }}
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "${{ env.PYTHON_VERSION }}"
 
       - name: Download API reference artifact
-        uses: actions/download-artifact@v8
+        uses: actions/download-artifact@3e5f45b2cfb9172054b4087a40e8e0b5a5461e7c # v8.0.1
         with:
           name: experimental-api-reference
           path: tmp_api_reference
@@ -86,7 +86,7 @@ jobs:
           fi
 
       - name: Create Pull Request
-        uses: peter-evans/create-pull-request@v8
+        uses: peter-evans/create-pull-request@c0f553fe549906ede9cf27b5156039d195d2ece0 # v8.1.0
         with:
           token: ${{ secrets.HAYSTACK_BOT_TOKEN }}
           commit-message: "Sync Haystack Experimental API reference on Docusaurus"
diff --git a/.github/workflows/licensing.yml b/.github/workflows/licensing.yml
index 170ded31..429fab50 100644
--- a/.github/workflows/licensing.yml
+++ b/.github/workflows/licensing.yml
@@ -12,7 +12,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
 
       - name: Check License Header
         run: docker run --rm -v "$(pwd):/github/workspace" ghcr.io/korandoru/hawkeye check
diff --git a/.github/workflows/project.yml b/.github/workflows/project.yml
index 5b98bccf..5420df41 100644
--- a/.github/workflows/project.yml
+++ b/.github/workflows/project.yml
@@ -10,7 +10,7 @@ jobs:
     name: Add new issues to project for triage
     runs-on: ubuntu-slim
     steps:
-      - uses: actions/add-to-project@v1.0.2
+      - uses: actions/add-to-project@244f685bbc3b7adfa8466e08b698b5577571133e # v1.0.2
         with:
           project-url: https://github.com/orgs/deepset-ai/projects/5
           github-token: ${{ secrets.GH_PROJECT_PAT }}
diff --git a/.github/workflows/pypi_release.yml b/.github/workflows/pypi_release.yml
index d4f8893d..b53ce324 100644
--- a/.github/workflows/pypi_release.yml
+++ b/.github/workflows/pypi_release.yml
@@ -14,10 +14,10 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v5
+        uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
 
       - name: Set up Python
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "3.12"
 
@@ -38,7 +38,7 @@ jobs:
           SLACK_WEBHOOK_URL: ${{ secrets.SLACK_WEBHOOK_URL }}
           VERSION: ${{ github.ref_name }}
         if: always()
-        uses: act10ns/slack@v2
+        uses: act10ns/slack@cfcc30955fe9377f4f55e1079e5419ee1014269f # v2
         with:
           status: ${{ job.status }}
           channel: "#haystack-notifications"
diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index aee6b5f1..6e5078a3 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -42,11 +42,11 @@ jobs:
   linting:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
       - name: Get changed files
         id: files
-        uses: tj-actions/changed-files@v47
+        uses: tj-actions/changed-files@24d32ffd492484c1d75e0c0b894501ddb9d30d62 # v47.0.0
         with:
           files: |
             **/*.py
@@ -54,7 +54,7 @@ jobs:
           files_ignore: |
             test/**
             .github/**
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "${{ env.PYTHON_VERSION }}"
 
@@ -81,9 +81,9 @@ jobs:
           - macos-latest
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
 
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "${{ env.PYTHON_VERSION }}"
 
@@ -97,7 +97,7 @@ jobs:
         # We upload only coverage for ubuntu as handling both os
         # complicates the workflow too much for little to no gain
         if: matrix.os == 'ubuntu-latest'
-        uses: coverallsapp/github-action@v2
+        uses: coverallsapp/github-action@5cbfd81b66ca5d10c19b062c04de0199c215fb6e # v2.3.7
         continue-on-error: true
         with:
           path-to-lcov: coverage.xml
@@ -122,9 +122,9 @@ jobs:
           - macos-latest
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/checkout@v5
+      - uses: actions/checkout@93cb6efe18208431cddfb8368fd83d5badbf9bfd # v5.0.1
 
-      - uses: actions/setup-python@v6
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: "${{ env.PYTHON_VERSION }}"
 
@@ -152,6 +152,6 @@ jobs:
       - integration-tests
     runs-on: ubuntu-slim
     steps:
-      - uses: deepset-ai/notify-slack-action@v1
+      - uses: deepset-ai/notify-slack-action@3cda73b77a148f16f703274198e7771340cf862b # v1
         with:
           slack-webhook-url: ${{ secrets.SLACK_WEBHOOK_URL_NOTIFICATIONS }}
diff --git a/.github/workflows/workflows_linting.yml b/.github/workflows/workflows_linting.yml
index c5a5e8e4..d321426e 100644
--- a/.github/workflows/workflows_linting.yml
+++ b/.github/workflows/workflows_linting.yml
@@ -10,9 +10,9 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
-        uses: actions/checkout@v6
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
 
-      - uses: actions/setup-go@v6
+      - uses: actions/setup-go@4b73464bb391d4059bd26b0524d20df3927bd417 # v6.3.0
         with:
           go-version: ">=1.24.0"