Paste JSON or Base64 — it will be detected and transformed automatically.
Paste or type JSON, Base64, or plain text…
Paste or click a sample above — it will be detected automatically.
Test suites live on good fixtures: UUIDs for primary keys, plausible IPs for log parsers, prime numbers for algorithm exercises, shuffled lists for pickers. Generate them here without scripts or dependencies — everything is produced on-device, so there's no rate limit and nothing about your project leaves the browser.
Every member tool is one click away inside the workspace above. This directory maps each job to the right starting point.
| Need | Generator |
|---|---|
| Unique identifiers | UUID generator (version 4) — dedicated page |
| Network fixtures & log samples | IPv4 / IPv6 address generators |
| Bulk structured fixtures | JSON / CSV / TSV generators — format output with the JSON Formatter |
| Algorithm practice | Prime, integer-range and fraction generators |
| Sampling & giveaways | Line shuffle and name picker |
| Fingerprinting hardware data | MAC address and hex string generators |
| Scripted fixture generation | Take it further with the Dart Compiler |
They are generated in your browser using standard random sources, which is ideal for test data and fixtures. For security-critical material such as keys or passwords, use a dedicated secrets generator instead.
UUIDs, IPv4/IPv6 addresses, times, primes, integers in a range, dates, names, line shuffles and pickers, MAC addresses, hex strings, fractions — plus bulk output as JSON, CSV or TSV for fixtures.
Pick the JSON generator, describe the shape you need, and paste the output straight into your mock server or test suite. CSV and TSV variants feed spreadsheets and database seeds.
Version 4 (random) is the safe default for identifiers. Other versions trade randomness for sortability or name-based derivation depending on your use case.
Last reviewed August 2026 · DataFormatter team — this tool processes data locally in your browser.