Base64 Encoder and Decoder
Encode and decode Base64 strings in your browser, with full UTF-8 support.
What is it?
Base64 is an encoding scheme that turns binary or text data into an ASCII string made of 64 safe characters: letters, digits, plus, slash and the equal sign for padding. It is widely used in email attachments, data URIs, JSON Web Tokens and any context where bytes need to travel through text-only channels. Our online Base64 encoder and decoder handles plain text, UTF-8 with accents and emojis, and the URL-safe variant used in JWTs and OAuth flows. Everything runs in your browser, so secrets, tokens or private payloads are never sent to a server.
How to use it
- Switch the mode to “Encode” or “Decode”.
- Paste your text or Base64 string into the input box.
- The result is computed live and shown in the output area.
- Use the URL-safe toggle when working with JWTs or query strings.
- Click “Copy” to copy the result, or “Swap” to send the output back into the input.
Why use this tool
Base64 is everywhere in modern software: it carries images inside HTML data URIs, encodes binary attachments inside emails, transports the payload of JSON Web Tokens, and embeds files inside JSON or YAML config. Doing the conversion in code is easy, but stepping outside an editor for a quick check should not require a heavy app or a sign up. Our tool is a no-friction option for developers, support engineers and security analysts. UTF-8 is handled correctly, so accented characters and emojis survive the round trip. The URL-safe variant replaces “+” with “-” and “/” with “_”, which is exactly what JWTs and OAuth bearer tokens require. Because everything runs locally, you can decode a token to inspect its claims without leaking the value to a third party.
Frequently asked questions
Is Base64 a form of encryption?
No. Base64 is an encoding, not an encryption. Anyone with the encoded string can decode it. Use real cryptography when you need confidentiality.
Why does my Base64 string end with “=” signs?
The “=” characters are padding so the encoded length is a multiple of four. They appear when the input length is not a multiple of three bytes.
What is the URL-safe variant?
URL-safe Base64 replaces “+” with “-” and “/” with “_” so the result can travel inside URLs without further escaping. JWTs and OAuth use this variant.
Does the tool support UTF-8?
Yes. The encoder normalizes input to UTF-8 before producing Base64, and the decoder converts the bytes back to a UTF-8 string.
Can it decode a JWT token?
Yes. Paste the middle segment of the JWT (the payload), enable URL-safe mode, and click decode to read the claims.