API Load Testing

Test your APIs under realistic traffic conditions

Simulate hundreds of concurrent API requests to find bottlenecks before your users do. loadtest.dev supports REST, GraphQL, WebSocket, and gRPC protocols with full k6 scripting.

What you get

  • Test REST, GraphQL, WebSocket, and gRPC APIs
  • Simulate up to 200 concurrent users for free
  • Real-time response time and error rate monitoring
  • Custom headers, authentication, and payloads
  • JavaScript-based test scripting with k6
  • Detailed percentile breakdowns (p50, p95, p99)
api-load-test.js
import http from 'k6/http';
import { check, sleep } from 'k6';

export const options = {
  vus: 100,
  duration: '2m',
};

export default function () {
  const res = http.get('https://api.example.com/users');
  check(res, {
    'status is 200': (r) => r.status === 200,
    'response time < 500ms': (r) => r.timings.duration < 500,
  });
  sleep(1);
}

Frequently Asked Questions

What APIs can I load test?

Any publicly accessible HTTP/HTTPS endpoint — REST APIs, GraphQL, WebSockets, and gRPC services. You can test internal APIs too if they're reachable from our global load zones.

How many concurrent requests can I simulate?

The free tier supports up to 200 virtual users. Each virtual user sends requests in a loop, so 200 VUs can generate thousands of requests per second depending on your API's response time.

Can I test authenticated APIs?

Yes. k6 scripts support custom headers, cookies, OAuth tokens, API keys, and session management. You have full control over the request lifecycle.

Ready to start api load testing?

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