Local processing RFC 4648

Complete Base64 encoding toolkit

Text, Base64URL, MIME, files, Data URI, Hex, Basic Auth, batch conversion, validation and JWT segment inspection in one responsive interface.

Privacy first

Conversion content stays in your browser. Logs contain only operation metadata and errors.

Text Base64 encoder and decoder

Supports Standard Base64, Base64URL and MIME wrapping with multiple character encodings.

Operation

Choose whether input is plain text or Base64.

Variant

Base64URL uses dash and underscore. MIME normally wraps at 76 characters.

Character encoding

Defines how text characters become bytes before Base64 conversion.

Line width

Use 0 for no wrapping. MIME defaults to 76 when left at 0.

Use equals padding

Standard Base64 normally uses equals signs so the length is a multiple of four.

Strict validation

Rejects mixed alphabets and malformed characters while decoding.

Ignore whitespace

Useful for MIME Base64 copied from email or wrapped text.

Input

0 chars0 B

Output

0 chars0 B

File to Base64 or Data URI

Files are read locally by the browser and are not uploaded to the server.

Drop a file here or choose a file

Large files may use significant browser memory, especially on phones.

Output format

Data URI includes the MIME type. Base64URL uses a URL safe alphabet.

MIME type override

Leave empty to use the MIME type reported by the browser.

Line width

Only applies to raw Base64. Use 0 for a single line.

Output

0 chars0 B

Base64 or Data URI to file

Paste Base64 or a Data URI, inspect it and reconstruct the original binary file locally.

Base64 or Data URI

Download filename

Used when downloading the decoded data.

MIME type

Automatically filled when a Data URI contains a MIME type.

Batch line conversion

Processes every input line independently and keeps the same line order.

Operation

Variant

Character encoding

Input

Output

Base64 validator and inspector

Detect alphabet, padding, whitespace, decoded byte size and malformed data.

Input

Valid-

Alphabet-

Decoded size-

Padding-

Whitespace-

Lines-

Standard Base64 and Base64URL

Hex and Base64

Hex or Base64 input

HTTP Basic Auth helper

Username Password

Base64 credential token

Basic

This helper only creates or decodes the Base64 credential value. Base64 is not encryption.

JWT Base64URL segment viewer

Decodes JSON in JWT header and payload segments without sending the token to the server.

Signature is not verified. Decoded content must not be treated as trusted authentication data.

JWT token

Header JSON

Payload JSON

Signature segment