JSON Formatter
Format, validate, minify and explore JSON with precise error locations. Runs locally.
Developer
Base64 & URL Encoder
Encode and decode Base64, URLs and HTML entities, convert files to data URIs and inspect JWT tokens. Unicode-safe, live as you type, and nothing leaves your browser.
UTF-8 & emoji safeFile → data URISafe for tokens
0 characters
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Paste a JSON Web Token
Header
Payload
The signature is not verified. Decoding happens locally, so it's safe to inspect production tokens.
Base64, URL and HTML encoding explained
- Base64 turns any bytes into plain text. Every 3 bytes become 4 characters, so output is about 33% larger. Text is converted to UTF-8 first, so emoji and non-Latin scripts round-trip correctly.
- URL encoding (percent-encoding) replaces characters that have special meaning in URLs, like spaces,
&and?, with%XXcodes. Use component mode for query values, and full-URL mode to clean up a whole link. - HTML entities escape
<,>,&and quotes so text displays literally instead of being parsed as markup, which helps prevent XSS. - JWTs are three URL-safe Base64 parts: header, payload and signature. The decoder shows the claims and turns
exp,iatandnbfinto readable dates.
Remember: Base64 is not encryption. Anyone can decode it. Use the steganography studio or proper encryption for secrets.
FAQ
What is Base64 encoding?
Base64 represents binary data using 64 printable characters (A–Z, a–z, 0–9, + and /). It's used to embed images in HTML or CSS, send attachments in email and carry binary data in JSON. It is an encoding, not encryption.
What is URL-safe Base64?
URL-safe Base64 replaces + with - and / with _ and usually drops the = padding, so the result can be used in URLs and file names. JWTs use this variant.
Does the JWT decoder verify signatures?
No. It decodes the header and payload so you can read the claims and expiry, but verifying a signature requires the secret or public key and should be done on your server.
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