JWT Decoder
Read a JWT’s header and claims, check expiry and verify HMAC signatures locally.
Base64 Encode & Decode
Encode or decode Base64 and URL-safe Base64, including emoji and non-Latin text. Convert small files to Base64 or build an HTTP Basic Authorization header.
- Free
- No sign-up
- Runs in your browser
How to use the Base64 Encoder / Decoder
- Choose Encode or Decode.
- Paste text, or pick a file to encode.
- Turn on URL-safe mode for JWTs and URL parameters.
- Copy the result.
Monitor what your code does after it ships
Send events to SensaCat’s ingest API and get alerted when jobs, webhooks and multi-step flows stall.
Frequently asked questions
No. Base64 is a reversible encoding that anyone can decode. It makes binary data safe to put in text formats; it doesn’t hide it.
A variant that replaces + with - and / with _, and often drops the = padding, so the value can be used in URLs and file names. JWTs use it.
Base64 turns every 3 bytes into 4 characters, so encoded data is about 33% larger than the original.
The client sends Authorization: Basic followed by the Base64 encoding of username:password. Because anyone can decode it, only use Basic authentication over HTTPS.
Related tools
JSON Formatter
Pretty-print, minify and validate JSON with exact line and column errors.
Webhook Signature Verifier
Check an HMAC webhook signature for Stripe, GitHub, Shopify, Slack or your own scheme.