diff --git a/.github/workflows/deploy.yml b/.github/workflows/deploy.yml
new file mode 100644
index 0000000..696c10b
--- /dev/null
+++ b/.github/workflows/deploy.yml
@@ -0,0 +1,76 @@
+name: Deploy
+
+on:
+  push:
+    branches:
+      - master
+  workflow_dispatch:
+
+permissions:
+  contents: read
+  id-token: write
+
+concurrency:
+  group: deploy-production
+  cancel-in-progress: false
+
+jobs:
+  deploy:
+    runs-on: ubuntu-latest
+    environment: production
+    env:
+      GCP_PROJECT_ID: ${{ vars.GCP_PROJECT_ID }}
+      GCP_REGION: ${{ vars.GCP_REGION || 'us-central1' }}
+      GCP_FUNCTION_NAME: ${{ vars.GCP_FUNCTION_NAME || 'progress' }}
+      GCP_RUNTIME: ${{ vars.GCP_RUNTIME || 'go124' }}
+      GCP_ENTRY_POINT: ${{ vars.GCP_ENTRY_POINT || 'Progress' }}
+      GCP_WORKLOAD_IDENTITY_PROVIDER: ${{ vars.GCP_WORKLOAD_IDENTITY_PROVIDER }}
+      GCP_SERVICE_ACCOUNT: ${{ vars.GCP_SERVICE_ACCOUNT }}
+    steps:
+      - name: Checkout
+        uses: actions/checkout@v4
+
+      - name: Validate deploy configuration
+        run: |
+          set -euo pipefail
+          required_vars=(
+            GCP_PROJECT_ID
+            GCP_WORKLOAD_IDENTITY_PROVIDER
+            GCP_SERVICE_ACCOUNT
+          )
+
+          for var in "${required_vars[@]}"; do
+            if [[ -z "${!var:-}" ]]; then
+              echo "Missing required repository variable: $var"
+              exit 1
+            fi
+          done
+
+      - name: Authenticate to Google Cloud
+        uses: google-github-actions/auth@v3
+        with:
+          workload_identity_provider: ${{ env.GCP_WORKLOAD_IDENTITY_PROVIDER }}
+          service_account: ${{ env.GCP_SERVICE_ACCOUNT }}
+          project_id: ${{ env.GCP_PROJECT_ID }}
+
+      - name: Deploy Cloud Function
+        id: deploy
+        uses: google-github-actions/deploy-cloud-functions@v4
+        with:
+          name: ${{ env.GCP_FUNCTION_NAME }}
+          project_id: ${{ env.GCP_PROJECT_ID }}
+          region: ${{ env.GCP_REGION }}
+          runtime: ${{ env.GCP_RUNTIME }}
+          entry_point: ${{ env.GCP_ENTRY_POINT }}
+          environment: GEN_2
+          source_dir: ./
+          all_traffic_on_latest_revision: true
+
+      - name: Smoke test deployed endpoint
+        env:
+          BASE_URL: ${{ steps.deploy.outputs.url }}
+          PROGRESS_PATH: ""
+        run: bash ./scripts/smoke.sh
+
+      - name: Print deployed URL
+        run: echo "Deployed URL: ${{ steps.deploy.outputs.url }}"
diff --git a/README.md b/README.md
index 7bd96fc..bcc229c 100644
--- a/README.md
+++ b/README.md
@@ -114,6 +114,13 @@ BASE_URL=https://geps.dev mise exec -- make smoke
 
 The smoke test validates status codes, headers, and basic content contract.
 
+If your `BASE_URL` already includes the function path (for example
+`https://REGION-PROJECT.cloudfunctions.net/progress`), set:
+
+```bash
+BASE_URL=https://REGION-PROJECT.cloudfunctions.net/progress PROGRESS_PATH="" mise exec -- make smoke
+```
+
 ## Deploy (Google Cloud)
 
 Set your project first:
@@ -135,10 +142,110 @@ After deploy, run smoke tests:
 BASE_URL=https://YOUR_DOMAIN_OR_FUNCTION_URL mise exec -- make smoke
 ```
 
+## Automated Deploy (GitHub Actions -> GCP)
+
+This repo includes `.github/workflows/deploy.yml` to deploy automatically on
+push to `master` (and manually via `workflow_dispatch`).
+
+### 1) Configure GitHub repository variables
+
+Required:
+
+- `GCP_PROJECT_ID` (example: `progress-markdown`)
+- `GCP_WORKLOAD_IDENTITY_PROVIDER` (full resource name)
+- `GCP_SERVICE_ACCOUNT` (deployer service account email)
+
+Optional (defaults are already set in workflow):
+
+- `GCP_REGION` (`us-central1`)
+- `GCP_FUNCTION_NAME` (`progress`)
+- `GCP_RUNTIME` (`go124`)
+- `GCP_ENTRY_POINT` (`Progress`)
+
+### 2) One-time GCP setup (OIDC/WIF, no JSON keys)
+
+Create deployer service account:
+
+```bash
+gcloud iam service-accounts create github-deployer \
+  --display-name "GitHub deployer for markdown-progress"
+```
+
+Grant deploy permissions on project:
+
+```bash
+PROJECT_ID=progress-markdown
+PROJECT_NUMBER=$(gcloud projects describe "$PROJECT_ID" --format='value(projectNumber)')
+SA="github-deployer@${PROJECT_ID}.iam.gserviceaccount.com"
+
+gcloud projects add-iam-policy-binding "$PROJECT_ID" \
+  --member="serviceAccount:${SA}" \
+  --role="roles/cloudfunctions.developer"
+
+gcloud projects add-iam-policy-binding "$PROJECT_ID" \
+  --member="serviceAccount:${SA}" \
+  --role="roles/run.admin"
+
+gcloud projects add-iam-policy-binding "$PROJECT_ID" \
+  --member="serviceAccount:${SA}" \
+  --role="roles/artifactregistry.writer"
+
+gcloud projects add-iam-policy-binding "$PROJECT_ID" \
+  --member="serviceAccount:${SA}" \
+  --role="roles/cloudbuild.builds.editor"
+
+gcloud projects add-iam-policy-binding "$PROJECT_ID" \
+  --member="serviceAccount:${SA}" \
+  --role="roles/iam.serviceAccountUser"
+```
+
+Create Workload Identity Pool + Provider:
+
+```bash
+PROJECT_ID=progress-markdown
+PROJECT_NUMBER=$(gcloud projects describe "$PROJECT_ID" --format='value(projectNumber)')
+POOL_ID=github
+PROVIDER_ID=github-oidc
+
+gcloud iam workload-identity-pools create "$POOL_ID" \
+  --project="$PROJECT_ID" \
+  --location="global" \
+  --display-name="GitHub Actions Pool"
+
+gcloud iam workload-identity-pools providers create-oidc "$PROVIDER_ID" \
+  --project="$PROJECT_ID" \
+  --location="global" \
+  --workload-identity-pool="$POOL_ID" \
+  --display-name="GitHub Actions Provider" \
+  --issuer-uri="https://token.actions.githubusercontent.com" \
+  --attribute-mapping="google.subject=assertion.sub,attribute.repository=assertion.repository,attribute.ref=assertion.ref"
+```
+
+Allow only this repository to impersonate the deployer service account:
+
+```bash
+PROJECT_ID=progress-markdown
+PROJECT_NUMBER=$(gcloud projects describe "$PROJECT_ID" --format='value(projectNumber)')
+POOL_ID=github
+REPO="gepser/markdown-progress"
+SA="github-deployer@${PROJECT_ID}.iam.gserviceaccount.com"
+
+gcloud iam service-accounts add-iam-policy-binding "$SA" \
+  --role="roles/iam.workloadIdentityUser" \
+  --member="principalSet://iam.googleapis.com/projects/${PROJECT_NUMBER}/locations/global/workloadIdentityPools/${POOL_ID}/attribute.repository/${REPO}"
+```
+
+Provider resource name to set in GitHub variable:
+
+```text
+projects/PROJECT_NUMBER/locations/global/workloadIdentityPools/POOL_ID/providers/PROVIDER_ID
+```
+
 ## CI
 
 - `CI` workflow runs `go test` and `go vet` on pushes and PRs.
 - `Smoke Tests` workflow can be run manually (`workflow_dispatch`) with a `base_url` input.
+- `Deploy` workflow deploys to GCP on `master` using OIDC/WIF.
 
 ## Contributing
 
diff --git a/scripts/smoke.sh b/scripts/smoke.sh
index 0d5e012..7805a59 100644
--- a/scripts/smoke.sh
+++ b/scripts/smoke.sh
@@ -7,6 +7,21 @@ if [[ -z "${BASE_URL:-}" ]]; then
 fi
 
 BASE_URL="${BASE_URL%/}"
+PROGRESS_PATH="${PROGRESS_PATH:-/progress}"
+
+if [[ -n "$PROGRESS_PATH" && "$PROGRESS_PATH" != /* ]]; then
+  PROGRESS_PATH="/${PROGRESS_PATH}"
+fi
+
+progress_url() {
+  local suffix="$1"
+  if [[ -z "$PROGRESS_PATH" ]]; then
+    echo "${BASE_URL}${suffix}"
+    return
+  fi
+
+  echo "${BASE_URL}${PROGRESS_PATH}${suffix}"
+}
 
 expect_status() {
   local expected="$1"
@@ -60,16 +75,16 @@ expect_body_contains() {
 
 echo "Running smoke tests against ${BASE_URL}"
 
-expect_status "200" "GET" "${BASE_URL}/progress/76"
-expect_header_contains "${BASE_URL}/progress/76" "Content-Type" "image/svg+xml"
-expect_header_contains "${BASE_URL}/progress/76" "Cache-Control" "max-age=300"
-expect_body_contains "${BASE_URL}/progress/76" "76%"
+expect_status "200" "GET" "$(progress_url "/76")"
+expect_header_contains "$(progress_url "/76")" "Content-Type" "image/svg+xml"
+expect_header_contains "$(progress_url "/76")" "Cache-Control" "max-age=300"
+expect_body_contains "$(progress_url "/76")" "76%"
 
-expect_status "400" "GET" "${BASE_URL}/progress/not-a-number"
-expect_status "400" "GET" "${BASE_URL}/progress/50?successColor=nothex"
-expect_status "405" "POST" "${BASE_URL}/progress/50"
+expect_status "400" "GET" "$(progress_url "/not-a-number")"
+expect_status "400" "GET" "$(progress_url "/50?successColor=nothex")"
+expect_status "405" "POST" "$(progress_url "/50")"
 
-expect_status "200" "GET" "${BASE_URL}/progress/150"
-expect_body_contains "${BASE_URL}/progress/150" "100%"
+expect_status "200" "GET" "$(progress_url "/150")"
+expect_body_contains "$(progress_url "/150")" "100%"
 
 echo "Smoke tests passed."