Random Secret Generator

Runs in browser Security

Uses crypto.getRandomValues to create secrets for JWT signing keys, session secrets, encryption keys and .env files at the length you choose.

Privacy: This tool runs entirely in your browser. Your input never leaves your device.

How to use Random Secret Generator

  1. Choose the number of random bytes (32 for JWT/session secrets).
  2. Pick a format and how many secrets you need.
  3. Optionally enter a variable name for .env output.
  4. Click Generate, then copy into your secret store.

Random Secret Generator features

  • crypto.getRandomValues — cryptographically secure randomness
  • Hex, Base64, Base64url, Base32, alphanumeric and printable-ASCII formats
  • Choose the entropy in bytes (8–1024); generate up to 100 secrets at once
  • .env style output (NAME=value)
  • Warns when the entropy is below 128 bits

Random Secret Generator example

A 32-byte Base64url secret for JWT_SECRET

Input:

Bytes: 32 · Format: base64url · Variable: JWT_SECRET

Output:

JWT_SECRET=tUSHdvHM79Cpnv67LfUnANNIJ4nhrH6bKsv59X6k1Uk

Frequently asked questions about Random Secret Generator

How many bytes should a JWT HS256 secret have?

At least 32 bytes (256 bits). HS384 needs 48 and HS512 needs 64 bytes. Longer is fine; the tool defaults to 32.

Which format should I choose?

Hex is safest to paste anywhere. Base64 is shorter. Base64url is safe in URLs and JWT keys. Use "alphanumeric" or "printable ASCII" when a system forbids certain characters — the length is adjusted to keep the requested entropy.

Is the randomness really secure?

Yes. Values come from crypto.getRandomValues, the browser's cryptographically secure generator backed by the operating system — the same source used by WebCrypto key generation.

Does anyone else see the secret?

No. It is generated in your browser and never transmitted or stored. Reload or click Regenerate to get a new one.

Technical notes

Each byte comes directly from the browser's CSPRNG. For alphabets whose size is not a power of two (alphanumeric, ASCII) the tool picks characters with unbiased random indices and increases the length so the result carries at least the requested number of bits.