Durable Counter

A minimal reference for Durable Objects: a single Counter class with persistent storage, exposed via HTTP routes. Use this pattern when you need strongly consistent state at the edge (rate limits, sessions, coordination).

API Endpoints

GET /counter

Returns the current counter value.

Example Request

curl "https://your-worker.workers.dev/counter"

Example Response

{ "value": 42 }

POST /counter/increment

Increments the counter by 1.

curl -X POST "https://your-worker.workers.dev/counter/increment"

POST /counter/reset

Resets the counter to 0.

curl -X POST "https://your-worker.workers.dev/counter/reset"

Use Cases

• Learn how to define and export a Durable Object class
• Shared counters or rate limiters across all edge locations
• Starting point for session storage or real-time coordination
• Understanding idFromName() for addressing a single global object

Deployment

curl "https://your-worker.workers.dev/counter"
curl -X POST "https://your-worker.workers.dev/counter/increment"

Local Development

cd apps/experiments/durable-counter
npm install
npm run dev

Configuration

wrangler.json declares:

• Durable Object binding COUNTER → class Counter
• Migration v1 registering the Counter class

Cloudflare Features Used

• Durable Objects - strongly consistent state and storage
• Workers - HTTP routes that call into the DO stub