diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
new file mode 100644
index 0000000..567c9cd
--- /dev/null
+++ b/.github/workflows/ci.yml
@@ -0,0 +1,62 @@
+name: CI
+
+on:
+  push:
+    branches: [main]
+  pull_request:
+    branches: [main]
+
+permissions:
+  contents: read
+
+concurrency:
+  group: ci-${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  lint:
+    name: Lint
+    runs-on: ubuntu-latest
+    timeout-minutes: 5
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+          cache: pip
+          cache-dependency-path: requirements-dev.txt
+
+      - name: Install Ruff
+        run: pip install --disable-pip-version-check -r requirements-dev.txt
+
+      - name: Ruff
+        run: ruff check api-service ingestion-service notification-service
+
+  test:
+    name: Test (${{ matrix.service }})
+    runs-on: ubuntu-latest
+    timeout-minutes: 30
+    strategy:
+      fail-fast: false
+      matrix:
+        service: [api-service, ingestion-service, notification-service]
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Set up Python
+        uses: actions/setup-python@v5
+        with:
+          python-version: "3.11"
+          cache: pip
+          cache-dependency-path: ${{ matrix.service }}/requirements.txt
+
+      - name: Install dependencies
+        run: pip install --disable-pip-version-check -r ${{ matrix.service }}/requirements.txt
+
+      - name: Pytest
+        working-directory: ${{ matrix.service }}
+        run: python -m pytest tests/ -q
diff --git a/scripts/run-ci.sh b/scripts/run-ci.sh
new file mode 100755
index 0000000..2d02e75
--- /dev/null
+++ b/scripts/run-ci.sh
@@ -0,0 +1,44 @@
+#!/usr/bin/env bash
+# Run the same lint and test steps as .github/workflows/ci.yml locally.
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
+cd "$ROOT"
+
+PYTHON="${PYTHON:-python3}"
+LINT_VENV="$ROOT/.venv"
+
+ensure_lint_venv() {
+  if [[ ! -d "$LINT_VENV" ]]; then
+    "$PYTHON" -m venv "$LINT_VENV"
+    "$LINT_VENV/bin/pip" install --disable-pip-version-check -q --upgrade pip
+    "$LINT_VENV/bin/pip" install --disable-pip-version-check -q -r requirements-dev.txt
+  elif ! "$LINT_VENV/bin/python" -m ruff --version &>/dev/null; then
+    "$LINT_VENV/bin/pip" install --disable-pip-version-check -q -r requirements-dev.txt
+  fi
+}
+
+run_service_tests() {
+  local service=$1
+  local service_dir="$ROOT/$service"
+  local venv="$service_dir/.venv"
+
+  echo "==> Test ($service)"
+  if [[ ! -d "$venv" ]]; then
+    "$PYTHON" -m venv "$venv"
+    "$venv/bin/pip" install --disable-pip-version-check -q --upgrade pip
+    "$venv/bin/pip" install --disable-pip-version-check -q -r "$service_dir/requirements.txt"
+  fi
+
+  (cd "$service_dir" && "$venv/bin/python" -m pytest tests/ -q)
+}
+
+echo "==> Lint (Ruff)"
+ensure_lint_venv
+"$LINT_VENV/bin/ruff" check api-service ingestion-service notification-service
+
+run_service_tests api-service
+run_service_tests ingestion-service
+run_service_tests notification-service
+
+echo "==> All CI checks passed"