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JSONL (JSON Lines) utilities, in the browser
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Sample datasets

realistic test files for the tools on this site · updated 3 May 2026

Every tool here works just as well with your own data, but sometimes you just want something to drop in and see what the output looks like. The files below are realistic, cover the obvious edge cases — including a couple of intentionally broken files for testing the validators — and range from a few KB up to a few MB so you can stress-test the streaming and chunked rendering. Each link saves the file to your machine; nothing is uploaded anywhere when you then drop it into a tool.

Small starter files

Larger datasets

Bigger files for benchmarking, testing memory usage, and seeing how the tools handle deep nesting, wide rows, and many thousands of lines. They're synthetic but schema-realistic and use stable seeds, so the same file is reproducible.

How to use these

Click any card to download the file, then drop it on the input pane of whichever tool fits. The intentionally-broken files (with names like broken-*) are useful for trying the validators — they should report specific line numbers and reasons.

Want one added?

If you have a real-world file you'd love to see as a sample (anonymised, of course), email [email protected] and I'll add it. The smaller and weirder the better — the goal is to have files that exercise the tools, not pretty demos.

— S., [email protected]