# HAR to Mocks | Turn captured responses into test fixtures

Need repeatable responses? Generate mocks from a HAR capture or compare two captures without uploading them. Check locally in your browser. No upload.

Canonical: https://tamperbox.dev/har-to-mocks

Docs: https://docs.tamperbox.dev/tools/har-to-mocks.md

Updated: 2026-10-26

Reviewed: 2026-10-26

## How it works

HAR to Mocks reads har capture locally and presents findings with the evidence behind them. A synthetic inventory capture includes successful JSON and a missing-resource response. The full method, every rule and worked examples are on [docs.tamperbox.dev](https://docs.tamperbox.dev/tools/har-to-mocks/).

## Limits and interpretation

Generated mocks do not reproduce timing, streaming, authentication or server logic. Captured response bodies and URLs can contain sensitive values; review before sharing. Inputs are limited to 1,000,000 characters per field. Nothing is fetched from addresses embedded in input. Explicit copies and downloads are under your control.

## Frequently asked questions

### Is my input uploaded?

No. Parsing and output generation run in your browser. Source values are not sent to a server.

### What does the opening example demonstrate?

A synthetic inventory capture includes successful JSON and a missing-resource response. It is synthetic data. Replace it with your own input to inspect a different case.

### Does a passing result prove my application works?

No. Generated mocks do not reproduce timing, streaming, authentication or server logic. Captured response bodies and URLs can contain sensitive values; review before sharing. Verify the result in your test environment before relying on it.

## References

- [Primary format and behavior reference](https://webperfwg.org/specs/HAR/Overview.html).