About JWT Signature Verifier
Verifies that a JSON Web Token is valid and has been signed with the provided secret / private key. The key should be either the secret for HMAC algorithms or the PEM-encoded public key for RSA and ECDSA.
Input: text. Output: structured JSON.
Format reference: JWT Verify background and specification
Example
Use “Try example” to load this public sample and its settings, then run it.
Settings used in this example
| Parameter | Example value | Input and choices |
|---|---|---|
| Public/Secret Key | "secret_cat" | Text |
Sample keys and passwords are public. Never use them to protect real data.
Input
eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJTdHJpbmciOiJTb21lU3RyaW5nIiwiTnVtYmVyIjo0MiwiaWF0IjoxfQ.0ha6-j4FwvEIKPVZ-hf3S_R9Hy_UtXzq4dnedXcUrXk
Result
{
"String": "SomeString",
"Number": 42,
"iat": 1
}Parameters
| Parameter | Default value | Input and choices |
|---|---|---|
| Public/Secret Key | "secret" | Text |
Before interpreting the result
Use the exact key encoding, mode, padding and IV expected by the source system. Historical ciphers are useful for learning and analysis. Encoding alone provides no confidentiality.
How to use this page
- Paste your input or open a local file.
- Adjust tool options if needed, then choose Run tool.
- Copy the result or download the original output bytes.
Inputs and results are not added to the public catalogue or saved in the URL. Processing happens in your browser; HTTP Request and DNS over HTTPS send the requests you explicitly run. Files up to 128 MiB can be opened; decompression and image tools may have smaller processing limits. Large results have a shortened preview. Text and HTML downloads use UTF-8; binary downloads preserve output bytes. Pasted text follows browser newline handling; open a file when exact input bytes matter.