URL Double Encoding
Encode text with percent-encoding several times, or peel a value layer by layer until stable and see which characters changed. Private.
More options
Text
Stays in your browserShortcuts: Ctrl+Enter run · Ctrl+Shift+C copy result · / search (use ⌘ on Mac)
Next steps
Done here? Use the Send to… menu on the result to carry it on to URL Parser or Query String Parser.
Free Online URL Double Encoding
Double-encoded values (%2520 for a space) appear in redirects, logs and security tests. Encode up to five times, or decode a value and see every layer. It gives developers a quick browser-based way to solve a focused url double encoding task before moving the result into a project.
How to use URL Double Encoding
Choose Encode or Decode. For Encode, set how many times. For Decode, every layer is listed until nothing is left to decode.
Common mistakes
- Decoding more times than the application does: the result is not what the program sees.
- Using full-URL mode on a value: it leaves : / ? & = alone, which a value usually needs encoded.
Frequently asked questions
Why is a value encoded twice?
A program encodes a value that was already encoded. A space becomes %20, and the % then becomes %25, giving %2520.
Why does this matter for security?
Filters that decode once can be bypassed by a value encoded twice. Testing shows which layer your application decodes.
What about incomplete sequences?
Bytes that are not valid UTF-8 (such as %E0%A4 alone) are shown as a replacement character and a note.
Is anything uploaded?
No. This tool runs in your browser and nothing you enter is sent to a server.
How do I use this url double encoding tool?
Use the interactive controls above; processing stays in your browser and the result is intended as a practical starting point for development work.
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