Base64 Decoder
Paste a Base64 string and decode it back into its original text, including standard and URL-safe variants.
- Runs in Your Browser
- Instant Results
- 100% Private
What Is Base64 Decoding?
Base64 decoding reverses Base64 encoding, converting a string of A-Z, a-z, 0-9, + and / (or their URL-safe equivalents) back into its original text. It is the tool to reach for whenever you have a Base64 string — from a JWT token, an API response, or an email header — and need to read what it actually contains.
This decoder automatically handles both standard and URL-safe Base64 input, so you don't need to know in advance which variant you're working with.
Who Uses This Tool?
For Business
Decode a Base64-encoded value returned by an API response.
For Personal Use
Decode a Base64 message to read its original content.
For Students
Explore how Base64 decoding works for a networking or web development course.
For Offices
Decode a configuration value stored in Base64 format.
Key Features
Handles Both Variants
Automatically decodes both standard and URL-safe Base64.
Instant Decoding
Output updates immediately as you paste in a Base64 string.
100% Private
Your text is never uploaded or stored.
One-Click Copy
Copy the decoded result straight to your clipboard.
Benefits
Read Encoded Values Instantly
See the real content behind a Base64 string in one click.
No Manual Padding Fixes
The tool automatically fixes missing padding characters.
No Software Needed
Decode directly in the browser — no command line required.
How to Use Base64 Decoder
Paste the Base64 String
Add the Base64-encoded text you want to decode.
Read the Decoded Result
The original text appears automatically.
Copy the Result
Use the Copy button to grab the decoded text.
Technical Details
| Detail | Value |
|---|---|
| Input | Standard or URL-safe Base64 text |
| Processing | No practical limit — handled entirely by your browser |
| Output | Exact decoding back to the original UTF-8 text |
Privacy & Security
What actually happens to your file when you use this tool.
100% Client-Side
This tool runs entirely inside your browser using JavaScript — nothing you type or generate is ever sent anywhere.
No Upload, Ever
There is no file upload and no server processing step — your data never leaves your device.
Works Offline
Once this page has loaded, the tool keeps working even without an internet connection.
Nothing Stored
Nothing you enter is saved on our servers — refreshing the page clears everything.
No Tracking of Your Input
We have no way to see what you type, generate or convert with this tool.
Tips
Remove Extra Whitespace First
If decoding fails, check for accidental line breaks or spaces copied along with the Base64 string.
Use This to Inspect JWT Payloads
JWT tokens are made of Base64-encoded segments — decode the middle segment to see the payload (note: this does not verify the signature).
Frequently Asked Questions
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