Percent Encoding Decoder - RFC 3986 Compliant
Encode or decode text using percent-encoding as defined by RFC 3986 for precise URI component handling. Ensures compliance for web APIs, query strings, and path segments.
How the Percent Encoding Decoder Works
Paste URL-encoded text into the input field. The decoder automatically detects and converts percent-encoded sequences. Results appear instantly as you type.
Percent encoding replaces special characters with % followed by two hex digits. Space becomes %20, slash becomes %2F. The decoder reverses this process.
Choose the character encoding - typically UTF-8 for modern URLs. The decoder converts hex bytes to characters using your selected encoding. Handles plus signs as spaces for form data.
When You'd Actually Use This
Debugging URL parameters
Received a URL with encoded parameters? Decode to see the actual values. Debug query strings with special characters or non-ASCII text.
Analyzing web traffic
Proxy logs show encoded URLs. Decode to understand what was requested. Security analysis often requires decoding suspicious URLs.
Processing form submissions
Form data arrives URL-encoded. Decode POST body or query parameters to get user input. Essential for web application development.
Working with REST APIs
API responses may contain encoded strings. Decode path parameters or query values. Understand the actual data being transmitted.
Investigating encoded payloads
Security researchers decode suspicious URLs. Attack payloads are often percent-encoded. Decode to analyze potential threats.
Handling international domains
IDN domains use punycode, but paths may have encoded Unicode. Decode to see actual international characters in URLs.
What to Know Before Using
Plus sign handling varies.In query strings, + often means space. In path segments, + is literal. This tool lets you choose how to handle plus signs.
Double encoding exists.Sometimes encoded strings get encoded again. %2520 is double-encoded space (%25 = %, so %2520 = %20). May need multiple decode passes.
Encoding must match.UTF-8 is standard for modern web. Older systems may use Latin-1 or other encodings. Wrong encoding produces garbled output.
Invalid sequences indicate problems.%ZZ where ZZ isn't valid hex indicates corruption. Incomplete sequences (%2) suggest truncation. These indicate data issues.
Pro tip: When debugging, decode step by step. First decode the URL, then examine parameters. Some parameters may themselves be encoded. Nested encoding is common in complex applications.
Common Questions
What characters get encoded?
Reserved characters: : / ? # [ ] @ ! $ & ' ( ) * + , ; =. Also spaces and non-ASCII. Unreserved (A-Z a-z 0-9 - _ . ~) stay as-is.
Why encode spaces as %20?
Spaces aren't allowed in URLs. %20 is the hex code for space (ASCII 32). In query strings, + is often used instead of %20 for spaces.
Can I encode with this tool?
This tool focuses on decoding. For encoding, use a URL encoder. Many tools provide both encode and decode functions.
What about punycode?
Punycode encodes international domain names differently. It uses xn-- prefix. This tool handles percent encoding, not punycode decoding.
Is %2F the same as /?
Yes, %2F decodes to forward slash. In path segments, they're equivalent. In some contexts, encoded slashes are treated differently for security.
Why are some characters still encoded?
Some characters remain encoded if they're part of the URL structure. The decoder converts percent sequences but preserves URL format.
Can this handle malformed input?
Invalid sequences are preserved as-is. %GG stays %GG since GG isn't valid hex. This helps identify encoding problems in the source data.
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