The JWT module lets you encode, decode and verify Json Web Tokens easily!

  do payload = {
    "user": "name",
    "somekey": {
      "somevalue": 42
    "exp": 1618064023,
    "iss": "CSML STUDIO"

  do jwt = JWT(payload).sign("HS256", "SECRET_KEY")
  say jwt

  do decoded = JWT(jwt).decode("HS256", "SECRET_KEY")
  say "{{decoded}}"

  do claims = {
    "iss": "CSML STUDIO"
  do verified = JWT(jwt).verify(claims, "HS256", "SECRET_KEY")
  say "{{verified}}"



exemple: JWT(data).sign(algorithm, secret)

  • data: json object to sign and convert to a JWT token

  • algorithm: see below

  • secret: a secret string used to sign the JWT

This method returns a properly encoded JWT as a string.


exemple: JWT(token).decode(algorithm, secret)

  • token: the token to decode

Note: decode does not try to verify that the token is valid. It simply decodes its payload back to the original form.

This method returns the full JWT data, in the form:{ "payload": { ... your data }, "headers": { "alg": ALG, "typ": "JWT" }}


exemple: JWT(token).verify(claims, algorithm, secret)

  • claims: set of claims (in JSON form) to verify the JWT against

Note: only valid claims are verified. See the list of official claims in the JWT specs here.

This method returns the full JWT data, in the form:{ "payload": { ... your data }, "headers": { "alg": ALG, "typ": "JWT" }}

Supported algorithms

JWT supports the following algorithms: HS256, HS384, HS512 (corresponding to HMAC using SHA-256, SHA-384 and SHA-512 respectively).

The secret key must be a valid, url-safe string.

Error handling

When a sign, decode or verify operation fails, Null is returned and a say Error(error_message) is emitted.

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