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.

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)
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

Miguel Trinidad