Haskell JWT Generator

Haskell JWT generator quickstart

Create a token with your public API key in the sub claim, a near-term Unix timestamp in exp, and an HS256 signature made with your private API key.

Sapling JWTs use HS256 with a sub claim containing your public API key and an exp claim containing a Unix timestamp. The examples use a one-hour lifetime; shorten it further when your application can refresh tokens easily.

Haskell HS256 · sub + exp

This example uses the jwt package's Web.JWT module.

{-# LANGUAGE OverloadedStrings #-}

import Data.Time.Clock.POSIX (getPOSIXTime)
import qualified Data.Text as T
import qualified Data.Text.IO as T
import System.Environment (getEnv)
import Web.JWT

main :: IO ()
main = do
  publicKey <- getEnv "SAPLING_PUBLIC_KEY"
  privateKey <- getEnv "SAPLING_PRIVATE_KEY"
  now <- getPOSIXTime

  let expiresAt = (round now :: Integer) + 3600
      claims = mempty
        { sub = stringOrURI (T.pack publicKey)
        , exp = numericDate (fromIntegral expiresAt)
        }
      token = encodeSigned
        (hmacSecret (T.pack privateKey))
        mempty
        claims

  T.putStrLn token

Generated token text/plain

eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.<base64url-claims>.<signature>

Return the compact token to the browser and pass it to Sapling.init as the key. Issue a fresh token after it expires; never send the private key.

Reference Frontend key management and JWT documentation All languages Choose another quickstart

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