Base64 decoder | Decode Base64 Easily
Decode Base64 data online. Convert Base64 strings to their original format, including text, images, and binaries. This tool supports multiple output formats for developers and data users.
What Is a Base64 Decoder?
What Is a Base64 Decoder?
A Base64 decoder converts Base64-encoded text back into its original data. Base64 represents binary data using only 64 printable ASCII characters (A-Z, a-z, 0-9, plus + and /), making it safe to embed in text-based systems. This tool decodes Base64 back to readable text, images, and files, and can also encode data in the other direction.
How to Use Base64 Decoder
- 1. Paste your Base64 encoded string in the input field
- 2. Click "Decode Base64" to convert the string
- 3. Choose to copy the decoded text or download as a file
- 4. For files, enter an optional filename before downloading
Where Base64 Is Used
| Use | Why |
|---|---|
| Embedding images in HTML/CSS | Inline data URLs (data:image/png;base64,...) avoid extra HTTP requests for small images and icons. |
| Email attachments (MIME) | Email transmits only ASCII text, so binary files are Base64-encoded to survive transport intact. |
| Storing binary in JSON/XML | These text formats cannot hold raw bytes, so files are Base64-encoded into a string value. |
| API tokens and auth headers | HTTP Basic Auth and JWTs use Base64 to pack credentials into header-safe text. |
| Encoding files for transfer | Base64 lets binary files move through text-only channels and copy-paste workflows without corruption. |
Use this tool from your AI agent
Free JSON API and Model Context Protocol (MCP) server. No signup, no API key, CORS open. Designed for Claude, ChatGPT, Cursor, scripts and frontend apps.
curl -X POST https://mate.tools/api/v1/base64-decode.php \
-H "Content-Type: application/json" \
-d '{"encoded":"aGVsbG8gd29ybGQ="}'import urllib.request, json
req = urllib.request.Request(
"https://mate.tools/api/v1/base64-decode.php",
data=json.dumps({"encoded":"aGVsbG8gd29ybGQ="}).encode(),
headers={"Content-Type": "application/json"},
)
with urllib.request.urlopen(req) as r:
print(json.load(r))const r = await fetch("https://mate.tools/api/v1/base64-decode.php", {
method: "POST",
headers: { "Content-Type": "application/json" },
body: JSON.stringify({"encoded":"aGVsbG8gd29ybGQ="}),
});
console.log(await r.json()); Add to claude_desktop_config.json (Claude Desktop), ~/.cursor/mcp.json (Cursor), or any other MCP-compatible client:
{
"mcpServers": {
"mate-tools": {
"command": "npx",
"args": ["-y", "@mate-tools/mcp-server"]
}
}
}