Mockoon is a popular open-source desktop app for local API mocking. ApiNotes is a cloud-based alternative that generates mock servers from OpenAPI specs instantly — no downloads, no local ports, no configuration files.
Mockoon is a fantastic desktop application with a polished GUI, route-level control, and a CLI for CI/CD integration. It's offline-first and gives you full control over every response. Best for developers who want detailed, hand-crafted mock configurations on their local machine.
ApiNotes skips the download entirely. Paste your OpenAPI spec in the browser, get a live cloud URL in under a minute. No ports to manage, no JSON config files to maintain. Perfect for quick prototyping, sharing mock URLs with teammates, and teams that already have an OpenAPI spec ready.
| Feature | Mockoon | ApiNotes |
|---|---|---|
| Setup required | Desktop app download (~100 MB) | None — browser only |
| Time to first mock | 5–15 min | < 60 seconds |
| OpenAPI import | Yes (one-time scaffold) | Native, spec-driven responses |
| Hosting | Local (localhost) | Cloud-hosted, public URLs |
| No sign-up required | ✅ | ✅ |
| Shareable mock URLs | ❌ (needs ngrok or deploy) | ✅ Built-in |
| Response templating | ✅ Handlebars + Faker.js | Schema-driven auto-generation |
| Request validation | ❌ | ✅ (Developer plan) |
| Latency simulation | ✅ | ✅ (Developer plan) |
| Proxy mode | ✅ | ❌ |
| CLI for CI/CD | ✅ (mockoon-cli) | API endpoint (POST to create) |
| API documentation | ❌ | ✅ Full docs platform |
| Free tier | Open source (MIT) | Free — 72h anonymous / 1K req |
| Platform | macOS / Windows / Linux | Any browser, any device |
Download the desktop app for macOS, Windows, or Linux (~100 MB). Create a new environment, add routes one by one, configure response bodies, headers, and status codes. Mockoon also offers a CLI (mockoon-cli) for running environments in CI. Setup takes about 5–15 minutes.
No download needed. Open the browser, paste or upload your OpenAPI spec (JSON or YAML), and click one button. All endpoints are generated automatically from your spec. Your mock URL is live within 60 seconds.
Mockoon can import OpenAPI specs to scaffold routes, but responses often need manual refinement. The import is a one-time conversion — changes to your spec require re-importing. Response generation from schema examples is limited.
Designed as an OpenAPI-first tool. Supports OpenAPI 3.0, 3.1, and Swagger 2.0 natively. Responses are generated using your spec's examples, x-example values, defaults, and schema definitions. Every endpoint becomes a realistic mock automatically.
Mocks run on localhost by default. To share, you'd need to expose your local port via ngrok or deploy the environment using Mockoon CLI on a shared server. Mockoon Cloud (paid) adds team sync. Environment files can be version-controlled.
Every mock gets a publicly accessible URL by default. Share it with teammates, use it in CI pipelines, or send it to clients. A shareable control panel shows usage stats, endpoint list, and cURL samples. No tunneling needed.
Excels at fine-grained control: dynamic templating (Handlebars/Faker.js), multiple responses per route with rules, response delays, sequential responses, and proxying to real APIs. A powerful choice for complex mock scenarios.
Responses are schema-driven. Developer plan adds request validation against your spec, configurable latency simulation, and error rate simulation. Less manual customization, but you get spec-accurate responses without writing any templates.
Desktop app and CLI are free and open source (MIT). Mockoon Cloud (team sync, collaboration) starts at $9/user/month. Self-hosting is always free, but you manage the infrastructure.
Anonymous mocks are free — no account, 72-hour validity, 500 requests. Free registered plan: 1 mock, 1K requests/month. Developer plan ($8/month): 2 persistent mocks, 50K requests/month, and a full API documentation platform included.
No download, no setup. Paste your OpenAPI spec and get a live mock URL in under a minute.