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Key Features
Instant Calculation
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Standard Base64 uses "+", "/", and "=" characters that have special meaning in URLs and file names, which is why URL-safe Base64 swaps them out — but forgetting to make that swap causes broken links and encoding bugs. This tool encodes or decodes text using the URL-safe Base64 variant, correctly handling the character substitution and padding removal.
How it works
Choose encode or decode mode and enter your text. For encoding, the tool base64-encodes the text, then replaces "+" with "-" and "/" with "_", and strips trailing "=" padding. For decoding, it reverses each of those steps before decoding.
- Enter mode.
- Enter input text.
- Click Calculate to see your results.
Examples
Encoding "Hello, World!"
The text "Hello, World!" encodes to "SGVsbG8sIFdvcmxkIQ" in URL-safe Base64 — no "+", "/", or "=" characters.
Who should use it
- Encoding a token or identifier for safe use directly inside a URL.
- Decoding the header or payload segment of a JWT for inspection.
Industry applications
- Web development and API design
- Authentication systems (JWTs and similar tokens)
Advantages
- Handles both the character substitution and padding removal/restoration automatically.
- Works in both directions (encode and decode) in one tool.
Limitations
- Decoded output that isn't valid printable text may display as garbled characters.
Common mistakes to avoid
- Trying to decode standard Base64 (with "+" and "/") through a strictly URL-safe decoder without converting the characters first.
- Forgetting that decoded binary or non-text data may not display correctly as plain text.
Best practices
- Always use the URL-safe variant (not standard Base64) for any value that will appear directly in a URL path, query string, or file name.
Tips
- To manually inspect a JWT's header or payload, copy just that segment (the text between the dots) and decode it here as URL-safe Base64.