Auto-Deploy to Vercel When a New Strava Activity Is Logged

Use a Cloudflare Worker to listen for Strava webhook events and trigger a Vercel deployment whenever you log a new activity.

Update (July 2026) — this pipeline now requires a paid Strava subscription.

Strava has moved API access behind its subscription. If the account that owns the API application isn't subscribed, the app goes Inactive and the whole /api/v3/* surface returns 403:
{ "message": "Forbidden", "errors": [{ "resource": "Application", "field": "Status", "code": "Inactive" }] }
That affects this setup in two places: the push_subscriptions calls in Steps 6–7 (registering the webhook), and the build-time activity fetch that the rebuild exists to refresh. The Cloudflare Worker itself is unaffected — it's just an HTTP relay — so if you already have a working subscription, existing webhook deliveries and the worker keep functioning. It's registering or re-registering that needs an active app.

Worth noting the failure mode is quiet: a deploy still gets triggered, the build still succeeds, and the site just rebuilds with no new Strava data. See the Notes section for how to catch that.

The Problem

My portfolio site fetches Strava activities at build time. The data is baked into the static export, so the site needs to rebuild whenever I log a new activity. I used to run a daily cron job with GitHub Actions, but that's unnecessary overhead for something that should be event-driven.

The goal: log a Strava activity → site rebuilds automatically.

How It Works

New Strava Activity → Strava Webhook → Cloudflare Worker → Vercel Deploy Hook → Site Rebuilds

Strava sends a webhook event when you log an activity. A Cloudflare Worker receives it and triggers a Vercel deploy hook to rebuild the site.

Why Not Connect Strava Directly to Vercel?

Vercel deploy hooks are simple POST endpoints — you hit the URL and it triggers a build. But Strava webhooks require your callback to:

Respond to a GET request with a challenge string during subscription setup
Accept POST requests with event data and respond with 200 OK

A Vercel deploy hook can't do either of those. You need something in between. A Cloudflare Worker is the simplest option — it's free, lightweight, and takes minutes to set up.

Prerequisites

You should have:

A Vercel project with your site deployed
A Cloudflare account (free tier works)
A Strava API application (create one here) in Active status — as of 2026 this requires an active Strava subscription on the owning account
Wrangler CLI available (npx wrangler --version to check)

1. Create a Vercel Deploy Hook

Go to Vercel Dashboard → your project → Settings → Git → Deploy Hooks
Name: strava, Branch: main
Click Create Hook
Copy the URL — it looks like https://api.vercel.com/v1/integrations/deploy/prj_xxxx/xxxx

2. Create the Cloudflare Worker

Create a new project with three files:

strava-webhook/
├── src/
│   └── index.js
├── wrangler.jsonc
└── package.json

package.json:

{
  "name": "strava-webhook",
  "version": "1.0.0",
  "private": true
}

wrangler.jsonc:

{
  "name": "strava-webhook",
  "main": "src/index.js",
  "compatibility_date": "2026-02-22"
}

src/index.js:

export default {
  async fetch(request, env) {
    const url = new URL(request.url);

    // Strava subscription validation (GET)
    if (request.method === "GET") {
      const challenge = url.searchParams.get("hub.challenge");
      const verifyToken = url.searchParams.get("hub.verify_token");

      if (verifyToken === env.STRAVA_VERIFY_TOKEN) {
        return new Response(JSON.stringify({ "hub.challenge": challenge }), {
          headers: { "Content-Type": "application/json" },
        });
      }
      return new Response("Forbidden", { status: 403 });
    }

    // Strava event notification (POST)
    if (request.method === "POST") {
      const event = await request.json();

      if (event.object_type === "activity" && event.aspect_type === "create") {
        await fetch(env.VERCEL_DEPLOY_HOOK, { method: "POST" });
        return new Response("Deploy triggered", { status: 200 });
      }

      return new Response("Ignored", { status: 200 });
    }

    return new Response("Method not allowed", { status: 405 });
  },
};

The worker handles two things:

GET — Strava sends this once during subscription setup. The worker echoes back the hub.challenge string to prove the callback URL is valid.
POST — Strava sends this whenever an event occurs. The worker checks if it's a new activity (object_type: "activity" and aspect_type: "create") and triggers the Vercel deploy hook. All other events (updates, deletes, athlete changes) are ignored.

3. Deploy the Worker

You need a Cloudflare API token. Use the Edit Cloudflare Workers template when creating one.

CLOUDFLARE_API_TOKEN=your_token npx wrangler deploy

You'll get a URL like https://strava-webhook.your-subdomain.workers.dev.

4. Set Worker Secrets

CLOUDFLARE_API_TOKEN=your_token npx wrangler secret put STRAVA_VERIFY_TOKEN
CLOUDFLARE_API_TOKEN=your_token npx wrangler secret put VERCEL_DEPLOY_HOOK

Secret	What to enter
`STRAVA_VERIFY_TOKEN`	Any string you choose (e.g., `my-strava-webhook-2026`)
`VERCEL_DEPLOY_HOOK`	The deploy hook URL from Step 1

5. Test the Worker

Before registering with Strava, verify the worker responds correctly:

curl -s "https://strava-webhook.your-subdomain.workers.dev?hub.verify_token=my-strava-webhook-2026&hub.challenge=test123&hub.mode=subscribe"

Expected response:

{"hub.challenge":"test123"}

6. Register the Strava Webhook

You need your Strava app's Client ID and Client Secret from Strava API Settings.

curl -X POST https://www.strava.com/api/v3/push_subscriptions \
  -F client_id=YOUR_CLIENT_ID \
  -F client_secret=YOUR_CLIENT_SECRET \
  -F callback_url=https://strava-webhook.your-subdomain.workers.dev \
  -F verify_token=my-strava-webhook-2026

Strava will send a validation GET to your worker. If it passes, you get back a subscription ID:

{
  "id": 331525
}

7. Verify the Subscription

Check that your subscription is active:

curl -G https://www.strava.com/api/v3/push_subscriptions \
  -d client_id=YOUR_CLIENT_ID \
  -d client_secret=YOUR_CLIENT_SECRET

To delete a subscription:

curl -X DELETE "https://www.strava.com/api/v3/push_subscriptions/SUBSCRIPTION_ID?client_id=YOUR_CLIENT_ID&client_secret=YOUR_CLIENT_SECRET"

Notes

Strava allows one webhook subscription per API application
Only new activity events trigger a deploy — updates, deletes, and athlete events are ignored
Strava retries failed webhook deliveries up to 3 times
Cloudflare Workers free tier allows 100,000 requests per day — more than enough
The Vercel deploy hook URL should be kept secret since anyone with it can trigger a build
Make the build fail loudly if the fetch dies. Because the rebuild is triggered by a webhook rather than by you, a 403 from Strava produces a green deploy with stale data and nothing in your inbox. If your fetch helpers swallow errors and return an empty array, the site will quietly render "No activities found" indefinitely. Either let the build fail on an API error, or fall back to a committed snapshot so the page still shows real data
If you stop subscribing, delete the push subscription (Step 7) rather than leaving it registered — otherwise Strava keeps attempting deliveries against an app that can no longer serve the data those deploys are fetching

Miguel Trinidad