Convert tools

JWT Signature Verifier

Verify a JWT signature against an explicitly selected algorithm and trusted key.

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Supports HS/RS/PS/ES 256, 384 and 512. HMAC uses UTF-8 secrets; RSA/EC use SPKI public PEM. Signature verification does not validate claims or trust the key.

Up to 100,000 UTF-16 units per input and 1,000,000 per result. See the supported formats and examples below.

How to use

  1. Verify a JWT signature against an explicitly selected algorithm and trusted key.
  2. Choose the mode or options, then run the tool.
  3. Review the result, then copy or download the TXT file.

Example

token + expected algorithm + trusted key → signatureValid

Details and limitations

Supports HS/RS/PS/ES 256, 384 and 512. HMAC uses UTF-8 secrets; RSA/EC use SPKI public PEM. Signature verification does not validate claims or trust the key.

Text stays in your browser; it is not sent to a conversion server.

FAQ

JWT Signature Verifier — What are the supported inputs and limits?

Supports HS/RS/PS/ES 256, 384 and 512. HMAC uses UTF-8 secrets; RSA/EC use SPKI public PEM. Signature verification does not validate claims or trust the key.

Format references

Tool page updated: