B64

Base64 Encoder/Decoder

LOCAL · Browser-Only

Encode text to Base64 or decode Base64 strings instantly

URL-safe

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What is Base64 Encoder/Decoder?

Base64 encoder and decoder online to convert any text string to Base64 format or decode Base64 back to readable text instantly.

Base64 encoding is commonly used for embedding binary data in text-based formats like JSON, HTML, email (MIME), and data URIs. Decode a Base64 string you found in code, inspect a JWT payload, read a Base64-encoded email header, or encode a Basic Auth credential for an HTTP request. The tool supports full Unicode text including emojis and non-Latin scripts, and provides instant results with one click. Switch between encode and decode modes, and use the swap feature to quickly reverse your conversion. All processing runs client-side in your browser - your data is never sent to any server or stored anywhere. No signup, no tracking, no data collection.

How to Use Base64 Encoder/Decoder

1Select the mode - 'Encode' to convert plain text to Base64 format, or 'Decode' to convert a Base64 string back to readable text
2Type or paste your input into the text field on the left side of the editor
3Click the Encode or Decode button to process your input and see the result instantly in the output panel
4Copy the result from the output field, or click 'Swap' to use the output as the next input for chained conversions

Frequently Asked Questions

What is Base64 encoding?

Base64 is a binary-to-text encoding scheme that represents binary data using a set of 64 ASCII characters (A-Z, a-z, 0-9, +, /). It is commonly used to embed images in HTML/CSS, transmit data over text-based protocols like email (MIME), and store binary data in JSON or XML.

Is Base64 encoding the same as encryption?

No. Base64 is an encoding scheme, not an encryption method. It does not provide any security - anyone can decode a Base64 string back to its original form. If you need to protect sensitive data, use proper encryption algorithms like AES instead.

Why does Base64 make data larger?

Base64 encoding increases the data size by approximately 33% because it represents every 3 bytes of input as 4 ASCII characters. This trade-off is necessary to safely transmit binary data through text-only channels like email, JSON, and URL parameters.

Can I encode Unicode text to Base64?

Yes. This tool fully supports Unicode characters including emojis, accented characters, and non-Latin scripts. The text is properly encoded using UTF-8 before Base64 conversion, so all characters are preserved accurately.

Is my data safe when using this Base64 tool?

Yes. All encoding and decoding happens entirely in your browser using JavaScript. Your text is never sent to any server, never logged, and never stored. This makes it safe to encode API tokens, configuration values, and other sensitive strings.

What are common uses for Base64 encoding?

Base64 is used to embed images in HTML/CSS via data URIs, encode email attachments (MIME), pass binary data through JSON APIs, encode authentication credentials in HTTP headers (Basic Auth), and store binary blobs in text-based configuration files.

How do I decode a Base64 string I found in code?

Switch to 'Decode' mode, paste the Base64 string into the input field, and click Decode. The original text will appear instantly in the output. This is useful for inspecting JWT tokens, data URIs, encoded API responses, and email headers.

Does this tool work without an internet connection?

Once the page is loaded, the encoding and decoding functions work entirely offline. The tool uses built-in browser APIs (btoa/atob with UTF-8 handling) and does not make any network requests during conversion.

What is the difference between standard and URL-safe Base64?

Standard Base64 uses + and / characters, which have special meaning in URLs. URL-safe Base64 (used in JWTs and query strings) replaces them with - and _ and usually drops the trailing = padding. If you are decoding a JWT segment, convert those characters back before decoding.

How do I decode a JWT with this tool?

A JWT has three dot-separated parts. Copy the first or second part (header or payload), switch to Decode mode, and paste it in. The decoded JSON shows the token claims. Note that JWT parts are Base64URL encoded, so swap any - and _ back to + and / first if decoding fails.

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Keep reading: TypeScript Cheat Sheet and jwt claims and algorithms reference. Doing this in code instead? See the hashing and security endpoints.

What is Base64 Encoder/Decoder?

Base64 encoder and decoder online to convert any text string to Base64 format or decode Base64 back to readable text instantly.

How to Use Base64 Encoder/Decoder

1Select the mode - 'Encode' to convert plain text to Base64 format, or 'Decode' to convert a Base64 string back to readable text

2Type or paste your input into the text field on the left side of the editor

3Click the Encode or Decode button to process your input and see the result instantly in the output panel

4Copy the result from the output field, or click 'Swap' to use the output as the next input for chained conversions