Disclaimer / simulated, not certified

Last updated: October 2026

APISimul does one thing — as a browser-based API mock simulator it intercepts fetch and XHR calls with a service worker so you can test a front end against fake endpoints without running a backend. The service worker registers a request handler that matches your rules by method and URL pattern, then returns the status code, latency and JSON body you configured before the request ever reaches the network. What follows concerns only that tool and the inputs involved in it.

In day-to-day use the tool works only from the mock rules, status codes and response bodies you define, and it is usually opened for things like building a UI before the real API exists. None of that reaches us, so none of it can be stored.

General information only

apisimul.com is an informational site. What APISimul produces are estimates of a calculation, not measured facts and not professional guidance.

Output you are expected to check

A developer tool generates a draft. Whatever APISimul emits — a type, a formatted document, a converted value — should be reviewed and tested against your own requirements before it is used anywhere that matters.

No guarantees

For APISimul, the assumption that matters is that your input sits inside the range the tool is built for. The service worker registers a request handler that matches your rules by method and URL pattern, then returns the status code, latency and JSON body you configured before the request ever reaches the network. Beyond that range — and wherever rounding, unit handling or browser rendering intrudes — the Site carries no warranty at all.

Third-party links

Any link to another site is provided for convenience. That content is outside our control and we are not answerable for it.

How the site is funded

Advertising keeps the Site free. Advertisers have no influence over any result, and the presence of an advertisement is not an endorsement.

Checking before you act

Before you act on any figure from this site, confirm it fits your circumstances. If you spot something wrong, use the contact page — we would rather correct it than defend it.