Base64 Encoder/Decoder
Encode text to Base64 or decode Base64 strings to plain text. Handles UTF-8 characters correctly.
Everything you need to know about Base64 encoding and decoding
Why use a Base64 encoder/decoder?
Base64 is the standard (RFC 4648) for converting binary data into printable ASCII text. It is used daily in emails (MIME), REST APIs, data URIs, and configuration storage. Encoding increases size by 33%, but guarantees compatibility with all text-based protocols.
This tool fully supports UTF-8: accented characters (e, n, u), CJK ideographs, and emojis are encoded and decoded without any data loss. Text is first converted to UTF-8 bytes before Base64 encoding, following best practices.
All processing happens in your browser via JavaScript. No data is ever sent to an external server, ensuring the privacy of your sensitive data (tokens, API keys, configurations).
Who uses this Base64 encoder/decoder?
- API developers
- Encode JSON payloads, images, or files to Base64 for transmission via REST APIs. Essential for data URIs (data:image/png;base64,...) that save one HTTP request per embedded resource.
- DevOps engineers
- Encode secrets, TLS certificates, or config files into environment variables or Kubernetes manifests. Base64 lets you store binary data in YAML or JSON files without corruption.
- Front-end developers
- Embed small images (icons, logos under 10 KB) directly in CSS or HTML as Base64 data URIs. This eliminates one network request per image and speeds up initial page rendering.
- Back-end developers
- Decode and inspect JWT tokens (JSON Web Tokens) whose header and payload are Base64url-encoded. Useful for debugging authentication flows without an external tool.
How does Base64 encoding/decoding work?
Paste your plain text or Base64 string into the input field. The tool accepts any length, including multiline text with special UTF-8 characters.
Click "Encode to Base64" to convert text into an RFC 4648-compliant Base64 string. Click "Decode from Base64" to recover the original text from an encoded string.
Copy the result in one click with the copy button. All processing runs client-side via JavaScript, with zero data sent to any server.
Frequently asked questions
- Why does size increase by 33% after Base64 encoding?
- Base64 encodes every group of 3 bytes into 4 ASCII characters. This 64-symbol printable representation results in a 33% size overhead. It is the trade-off defined by RFC 4648 to ensure compatibility with text-based protocols like SMTP and HTTP.
- Does this tool handle accented characters and emojis?
- Yes. The tool first encodes text to UTF-8 before converting to Base64, which guarantees full support for accented characters (e, n, u), CJK ideographs, and emojis. Decoding performs the reverse operation without any data loss.
- What is Base64 used for in web development?
- Base64 is used to embed images as data URIs in CSS or HTML (saving one HTTP request), encode email attachments in MIME, transmit binary data in JSON APIs, and temporarily store small files in localStorage.
- Is my data sent to a server?
- No. Encoding and decoding happen entirely in your browser via JavaScript. No data is transmitted, stored, or logged on any server. You can even use the tool offline once the page is loaded.