Mock APIs without the bloat.
No workspace. No collection. No team plan. Just a URL that returns what you tell it to. REST and LLM streaming. Free.
- Skip the 15-minute setup ceremony Postman requires for a mock server
- REST mocking + LLM streaming in one place - Postman offers neither streaming support
- Zero accounts, zero configuration, zero cost
For developers who want a mock endpoint, not a subscription.
The Problem
API mocking should not require an enterprise platform.
But Postman buries mock servers inside collections, behind mandatory account creation. You create an account. Create a workspace. Build a collection. Add requests. Define response examples. Deploy a mock server. Configure the URL. That is the workflow to return a JSON object.
And after all that, Postman's mock servers don't support LLM streaming. No Server-Sent Events. No token-by-token delivery. If you're building AI features, Postman can't help with the streaming part.
Scenario
A developer needs to test a webhook integration. She needs an endpoint that accepts POST requests and returns a 200. In Postman: create account, create workspace, create collection, create request, create example, create mock server, copy URL, configure CORS. In mockapi.dog: open the page, set the method to POST, click save.
The Solution
mockapi.dog does one thing: it mocks APIs.
It doesn't manage your API lifecycle. It doesn't document your endpoints. It doesn't run performance tests. It doesn't provide governance dashboards.
It creates mock endpoints. REST endpoints with any JSON response, any HTTP method, any status code. LLM streaming endpoints with OpenAI, Anthropic, or generic SSE formats. With configurable delays, error rates, and conditional errors.
No account. No API key. No installation. No configuration file. No team workspace. No billing page. You open the browser. You define a response. You get a live URL.
Feature Breakdown
No signup, no login, no account
Postman requires account creation to use mock servers. mockapi.dog doesn't have accounts. There's nothing to sign up for. Open the page and start.
REST + LLM streaming in one tool
No other free mocking tool supports both traditional REST responses and LLM-style token streaming over SSE. Build your CRUD endpoints and your AI chat mocks in the same place.
Nothing to install
No 500MB Electron desktop app. No CLI tool. No browser extension. No npm package. Everything happens in the browser. Your mock endpoint is one page load away.
Full response control without the UI maze
Pick your method. Pick your status code. Write your JSON. Set optional delays and error rates. Save. No tabs, panels, drawers, and modals to navigate. One form.
Delay and error simulation included - not gated
Postman gates mock servers behind team plans for advanced features. mockapi.dog includes delay injection, random error rates, and conditional header-based errors on every endpoint. Free.
CORS that just works
Every endpoint returns proper CORS headers. No configuration. No proxy. No middleware. Your frontend calls the mock URL directly from localhost.
mockapi.dog vs Postman
| Feature | mockapi.dog | Postman |
|---|---|---|
| What it is | Mock API tool | Full API lifecycle platform |
| Time to first mock | ~5 seconds | ~5 minutes |
| Account required | ||
| Desktop app required | Recommended | |
| LLM streaming (SSE) | ||
| Delay simulation | ||
| Error simulation | Random + conditional | Limited |
| API design tools | ||
| API documentation | ||
| Test automation | ||
| API monitoring | ||
| Team collaboration | ||
| Cost | Free, no limits | Freemium, paid teams |
Honest tradeoffs
mockapi.dog is deliberately narrow. It does not do API design, documentation, automated testing, monitoring, or team collaboration. If your job requires a full API development platform with governance, Postman serves that need. mockapi.dog exists for the moment you need a mock endpoint and everything else is in the way.
Use Cases
Replacing Postman for quick mocking
You don't want to open a 500MB Electron app to mock a single GET endpoint. Open mockapi.dog in a browser tab. Create the endpoint. Close the tab when you're done. No workspace left behind.
Startup MVP validation
You're validating an idea. The backend doesn't exist. You need three API endpoints to make the prototype work. Create them in under a minute. Show the prototype to users. Decide whether to build the real thing.
Simulating rate limits and failures
Your app needs to handle rate-limited APIs gracefully. Set up a mock endpoint with a 50% error rate returning 429. Test your backoff logic, queue management, and user-facing error messages.
Webhook testing without infrastructure
You need to point a webhook at an endpoint that accepts POST requests and returns 200. Don't set up a tunnel. Don't spin up a local server. Create a POST mock endpoint. Use the URL.
Developer Experience
The entire product is one page. There are no tabs to navigate, no settings to configure, no projects to manage.
Open the browser. The endpoint shortcode is already generated. Type your JSON response. Pick the HTTP method and status code. Optionally add delay or error simulation. Click save.
You have a live URL. Use it. There is nothing else to learn.
No documentation is required to get started because there is nothing to set up. No onboarding flow because there is no account. 5 seconds from page load to working endpoint.
Pricing
Free. No limits. No signup.
There is no pricing page because there is nothing to price. There are no tiers because there is nothing to upsell.
mockapi.dog is a free, focused tool from a solo developer. It doesn't need a revenue model because it doesn't need a sales team, a customer success team, or an enterprise division. The tool is free. It stays free.
Ready to start?
Postman wants you to create an account, build a workspace, configure a collection, deploy a mock server, and maybe talk to sales. mockapi.dog wants you to type some JSON and click save. Choose accordingly.