Encoder / Decoder
Encode and decode Base64 for text or files, decode JWT tokens to read their claims, and generate hashes and UUIDs. Free, instant, nothing leaves your browser.
Base64, hashes and JWTs in one place
Paste text or drop a file and the Encoders tab returns its Base64 form alongside MD5, SHA-1, SHA-256 and SHA-512 digests in a single pass. If the input is itself valid Base64 that decodes to readable text, the decoded string appears too, so the same box works in both directions. Tick the HMAC option and enter a key to get keyed hashes instead of plain ones, which is what webhook signatures and API request signing usually require.
The JWT tab splits a token into its header and payload and pretty-prints both as JSON. It does not verify the signature, so treat it as a way to read claims, not to trust them. Switching to encode mode builds a token from a header, a payload and a secret using HMAC-SHA256, which is handy for crafting test tokens against a local API. A third tab generates UUIDs in v1, v4 or v7 format, up to 100 at a time.
Base64 is often mistaken for encryption. It is a reversible encoding that turns binary into printable characters, and anyone who sees the output can recover the input. Hashes go the other way: one-way and fixed-length, useful for integrity checks but not for hiding data. Everything here runs in the browser, so pasting a production token or a secret key does not send it anywhere.
Frequently asked questions
Is Base64 encryption?
No. Base64 is an encoding, not a cipher: it has no key, and anyone can decode it back to the original bytes. Use it to carry binary data through text-only channels, never to protect it.
Does the JWT decoder verify the signature?
No. It decodes the header and payload so you can read the claims, but it does not check that the signature is valid. Verification needs the issuer's secret or public key and should happen on the server.
What is HMAC for?
HMAC combines a hash with a secret key so that only someone holding the key can produce or check the result. APIs such as webhook providers use it to sign payloads; tick HMAC, enter the shared secret and compare the output with the signature header.
Can I hash a file instead of text?
Yes. Switch the input to File and choose one; Base64 and all four hashes are computed from the raw bytes. The whole file is read into memory first, so very large files take a moment.