Base64 Decoder
Decode base64 and base64url to UTF-8 text in your browser. Handles missing padding and whitespace automatically. Free, private, instant.
About this tool
Decode standard base64 and URL-safe base64url back to readable UTF-8 text. Whitespace and line breaks in the input are ignored, and missing padding is repaired automatically. Those are the two issues that make strict decoders reject perfectly recoverable data.
Because JWT segments, basic-auth headers, and data URIs are all base64 under the hood, this is a general-purpose inspection tool for opaque-looking strings.
Common uses
- Inspect a mystery string from a config file, header, or URL parameter.
- Decode basic-auth credentials or webhook payloads while debugging.
- Recover text from data: URIs.
Automate via API
The same conversion is available as a REST endpoint for scripts, pipelines, and backends:
curl -X POST https://payloadly.com/api/v1/tools/base64-decoder \ -H "Content-Type: text/plain" \ -H "X-Api-Key: YOUR_API_KEY" \ --data-binary @input.txt
Worked examples
Real payloads from tools people use daily, with the exact output this converter produces. Every example runs in your browser, so you can load one and adapt it to your own data.
Decode a Basic auth header
Strip the leading 'Basic ' from an Authorization header and paste the rest to recover the 'username:password' pair while debugging.
YWxhZGRpbjpvcGVuc2VzYW1l
aladdin:opensesame
Decode a JWT payload segment
A JWT is three base64url segments joined by dots. Paste just the middle segment to read the claims; padding and URL-safe characters are handled automatically.
eyJzdWIiOiIxMjM0NTY3ODkwIiwibmFtZSI6IkpvaG4gRG9lIiwiaWF0IjoxNTE2MjM5MDIyfQ
{"sub":"1234567890","name":"John Doe","iat":1516239022}Base64 notes
Base64 encodes binary or text data into a 64-character alphabet so it can travel through text-only channels: data URIs, basic auth headers, email bodies, and JSON payloads.
- Base64 is encoding, not encryption; anyone can decode it.
- URL-safe base64 swaps `+/` for `-_` and often drops `=` padding.
- Encoding inflates size by roughly 33%.
Frequently asked questions
Is my data uploaded to a server?
No. This tool runs entirely in your browser using JavaScript, and there are no ads on the page. Nothing you paste or drop here is uploaded, logged, or stored, and you can verify that yourself: open your browser's developer tools and watch the Network tab while you convert (no requests leave the page), or disconnect from the internet after the page loads and keep working.
Is there a size limit or a fee?
The browser tool is free with no signup and comfortably handles files up to tens of megabytes (limited by your device's memory). For automated or bulk processing inside your own scripts and pipelines, use the paid REST API.
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