# Base64 encoder and decoder: run it free, or from your agent

Encode or decode Base64 for text and files, with UTF-8, the URL-safe alphabet and data URLs. Local only.

## Prompt

Use looot to run this catalog endpoint and save the file it returns: [endpoint]. 1. Set up https://looot.ai/skill.md. 2. Read the endpoint's parameters and price before you call. 3. Run it. 4. If a field holds Base64 data, decode it, guess the file type from its first bytes and save it with a matching extension. 5. Return the file name and size.

## What it needs

Text, a file, or a Base64 string

## What comes back

- Base64 text
- decoded text
- data URL of a file
- decoded file download
- size in characters and bytes

## Endpoints and providers

None. The tool on the web page runs in the browser and calls no endpoint.

## What it costs

Nothing. The tool on the web page runs in the visitor's browser: no account, no API call and no limit per hour. The prompt above runs the same job from your own looot account with current data, billed per call.

## Auth headers

Build or read a Basic auth header value.

## Data URLs

Inline a small icon or font in CSS or HTML as a data URL.

## Read a payload

Decode a Base64 field from an API answer, a webhook or a config file.

## Save a file

Turn Base64 image or PDF data back into a file you can open.

## How do I decode Base64?

Switch to Decode and paste the Base64. The text appears below. If the bytes are not text, such as an image, the page shows the first bytes in hex and offers the file as a download.

## What is URL-safe Base64?

A variant that uses - and _ instead of + and /, so the result can sit in a URL or a file name. JWTs use it without padding. The decoder accepts both forms.

## Does it handle accents, Chinese and emoji?

Yes. Text is encoded as UTF-8 before Base64, so every character survives the round trip. The browser's own btoa function fails on those characters, which is a common bug this avoids.

## Can I encode an image or a PDF?

Yes, files up to 10 MB. Use Encode a file to get the Base64 text and a data URL you can paste into HTML or CSS.

## Is Base64 encryption?

No. It is an encoding anyone can reverse. Never treat Base64 as a way to hide a password or a key.

## Why is the Base64 longer than the input?

Base64 writes every 3 bytes as 4 characters, so the output is about a third larger than the input.

## Are my files uploaded?

No. Files are read and encoded in your browser and never leave your machine.

## Related tools

- /free-tools/jwt-decoder
- /free-tools/json-formatter
- /free-tools/qr-code-generator

## Last reviewed

2026-10-14.