Base64 Decoder
Decode Base64 strings back to text, images or files — including JWTs and data URIs.
Processed locally in your browser. Nothing you enter is uploaded or stored.
- Decodes as UTF-8, so emoji and accented characters come back intact.
- Handles URL-safe Base64 (`-`/`_`, no padding) automatically — paste a JWT segment directly, no need to fix it up first.
- Recognizes a `data:image/...;base64,` URI, or a raw image payload by its file signature, and shows the actual image with a download button instead of garbled text.
- Flags invalid input clearly instead of returning garbled text.
- Runs in your browser — safe for tokens and encoded payloads.
Why this is private
- Processed locally in your browser. Nothing you enter is uploaded or stored.
- Open your browser's DevTools → Network tab while using this tool — you won't see a request carrying your input, because it never leaves your device.
- Nothing you enter is uploaded to a server or shared with us — the processing happens entirely on your device.
Overview
Decodes a Base64 string — including URL-safe Base64 (as used in JWTs) and full `data:` URIs — back into readable text, or shows and offers a download when the decoded bytes are actually an image or another binary file.
How to use it
- 1Paste a Base64 string, a data: URI, or a JWT segment.
- 2Text decodes instantly; an image or other binary payload shows a preview or a download button instead.
Examples
Base64 to text
Input
SGVsbG8sIHdvcmxkIQ==
Output
Hello, world!
Frequently asked questions
What people use it for
Read a Base64 field from an API or configDecode a value stored or transmitted as Base64 to see what it actually contains.
View an image from a data URIPaste the full `data:image/png;base64,...` string and see the actual image, with a one-click download.
Decode a Basic Auth headerTurn the string after `Authorization: Basic` back into `user:password`.
Check what a JWT segment holdsPaste a single base64url segment straight from a token — it decodes without needing padding or character fix-ups first (for the full token including signature verification, use the JWT Decoder).
Related guides
- How to read JSON with a tree viewerA tree viewer turns a wall of brackets into a structure you can expand, search and copy paths from. Here's how to use one effectively.
- JSON parse errors explained: 'Unexpected token', 'Expected comma or brace', and the restWhat each common JSON error message actually means, the usual cause, and how to find the spot fast using line and column.
- How to format JSON (and actually understand the errors)JSON looks like a JavaScript object but follows stricter rules. Here's what those rules are and how to read the errors when they're broken.
Related tools
All developer toolsBase64 EncoderEncode text to standard or URL-safe Base64.URL DecoderDecode percent-encoded URLs back to plain text — automatically unwraps multiple layers.JWT DecoderDecode JWT headers and payloads, and verify HMAC signatures with a secret.JSON Viewer & FormatterView, format, validate, edit and beautify JSON with an interactive tree view, plus a shareable link.
Ready to use Base64 Decoder?
Base64 Decoder