randarium
Test Data

Random Hash Generator

Create random hexadecimal strings with the bit-lengths of common hash algorithms (MD5, SHA-1, SHA-256, SHA-512). These are synthetic test hashes shaped like real digests but are not actual hashes of any input data.

Also known as: digest · checksum · hash value

seeded · synthetic data

Presets

Output

No output yet — set your options and hit .
About this tool, tips & examples

What it does

The Random Hash Generator produces hex strings with the exact shape of cryptographic digests — MD5 (32 hex chars), SHA-1 (40, also the git commit-hash format), SHA-256 (64), and SHA-512 (128) — in upper or lowercase. These are random values, not real hashes of any input: perfect fixtures wherever your data model stores a digest. Up to 1,000 per run, seeded.

Common use cases

  • Database seeding — checksum and content-hash columns filled with format-correct values.
  • Git tooling fixtures — commit-hash-shaped values (a preset) for testing UIs, parsers, and shortening logic.
  • API testing — ETag, digest, and signature-shaped fields in mock responses.
  • Cache key fixtures — realistic digest-shaped keys for cache-handling code.

Settings

  • Algorithm — MD5, SHA-1, SHA-256, or SHA-512 shapes (presets include a git-commit style).
  • Uppercase hex — for systems that store digests uppercased.
  • Mode / How many — 1 to 1,000 values, exportable as text, CSV, or JSON.
  • Seed — identical seed + settings = identical values.

Privacy note

Values are generated locally in your browser and never uploaded. They hash nothing — a “SHA-256” here is 64 random hex characters, unlinked to any input, and must never be presented as a real integrity check.

FAQ

Why fake hashes instead of hashing something? For fixtures, the shape is what matters — length, charset, case. Random values are faster, seedable, and can’t accidentally leak what was hashed.

Can I verify these against anything? No — that’s the point and the warning. If your test needs hash(x) == stored, compute a real digest in the test; use these where the value is opaque data.

Which length is which? 32 hex chars = MD5, 40 = SHA-1/git, 64 = SHA-256, 128 = SHA-512. Handy when reverse-engineering what an unlabeled column stores.