A HAR file is the JSON a browser's network panel exports: a log of requests, responses, timings and headers. Tools that read them include performance dashboards, test harnesses and support pipelines where a user is asked to attach a network trace.

har/simple-3-requests.har describes one page and three requests (a document, a stylesheet and an image) with fixed start times and timings. Because every timestamp is pinned, the file is the same on every build rather than a record of when it happened to be generated, so it can be committed as a test fixture and compared byte for byte.

It is valid JSON, so it doubles as a test of nested-structure handling: a HAR is considerably deeper than the flat objects most JSON fixtures provide, and it is served as application/json, which is worth checking against tools that expect a .har extension to mean something else.

Related formats: JSON and the web app manifest.

Every HAR file in one command, each checked against its hash: npx loremfile get --format har, or loremfile get --format har after pip install loremfile.

Sample HAR file for testing network tools, free and CC0

Related formats