Base64 is an encoding scheme that represents binary data, including images and files, as text built from a limited character set. You may encounter it in API responses, email, configuration files and data URLs.
Base64 is not encryption. The encoded text may not be readable at a glance, but anyone with a compatible decoder can recover the original data. It must not be used to protect passwords or secrets.
How Base64 works
Base64, as defined by RFC 4648, divides input data into six-bit groups and maps those groups to 64 printable characters. Three bytes of input are normally represented by four output characters, so encoded data is generally larger than the original.
The = characters sometimes found at the end are padding used when the input length is not a multiple of three bytes. Base64url is a related alphabet that replaces + and / with characters that are easier to use in URLs and file names.
Base64, encryption and hashing
| Method | Reversible? | Main purpose |
|---|---|---|
| Base64 | Yes | Represent binary data as text |
| Encryption | Yes, with a key | Protect content from unauthorized readers |
| Hashing | Normally no | Compare identity or detect changes |
The security considerations in RFC 4648 explicitly note that base encoding can visually hide recognizable information but provides no computational confidentiality.
Common uses
Data URLs
Small images and other assets can be embedded as data:image/png;base64,.... The browser’s FileReader.readAsDataURL() method returns a data URL that includes this prefix. Remove the leading data:*/*;base64, declaration when a decoder expects only the Base64 payload.
JSON and APIs
JSON has no native binary value, so Base64 is sometimes used to carry small binary values as strings. Because encoding increases size, large files are usually better handled as normal file transfers or object-storage uploads.
Configuration and test data
Encoding can make short values with line breaks or control characters easier to copy. That convenience does not make a secret safe to commit to a repository.
Data you should not rely on Base64 to protect
- Passwords and recovery codes
- API keys, access tokens and private keys
- Personal information or confidential documents
- Any file that must not become public
Encoding adds no access control. Use appropriate encryption, secret management and authorization for sensitive data.
Convert locally with Tools Hub
The Tools Hub Base64 converter runs in your browser. Text and files are not uploaded to a Tools Hub server.
- Enter text or choose a file
- Select encode or decode
- Copy or save the result when needed
Browser-only processing still requires care on shared devices. Check the clipboard, screen sharing and destination before posting an encoded value to a chat, ticket or public issue.
Convert in your browser
Base64 Converter
Encode and decode text or files without uploading them to a server.
Summary
- Base64 is an encoding scheme, not encryption
- Encoded output is larger than the original data
- Do not use it to protect secrets
- Use it for specific transport formats such as data URLs and small JSON values
- Treat an encoded string with the same sensitivity as its original data