URL decode converts percent-encoded strings like %2F and %20 back into readable text so you can debug query parameters, redirects, and encoded payloads. SWEDevTools: Prism decodes locally in your browser (no server), supports Unicode, and can optionally treat “+” as a space for application/x-www-form-urlencoded inputs. Paste the encoded string, click Run, and inspect the decoded result immediately—then chain it into URL parsing or JSON tools in a pipeline. Because SWEDevTools: Prism is local-first and works offline as an installable PWA, you can safely decode production URLs and sensitive parameters without pasting them into third-party sites. It is a reliable way to make logs and links readable before deeper troubleshooting.
Converting %XX sequences back into characters.
%20 represents a space.
When input is application/x-www-form-urlencoded.
Malformed percent sequences like %ZZ are invalid.
No—processing is local.
Yes, but often you decode components; then parse the URL for structure.
Use URL Encode.
Yes—install the PWA.
Percent decoding is the reverse of percent encoding: each %XX sequence is converted back to the original byte it represents. This is the standard mechanism browsers and servers use to interpret encoded characters in URLs, query strings, and form submissions.
Yes. International characters in URLs are typically encoded as multi-byte UTF-8 sequences, each byte represented as a percent-encoded triplet. The decoder reassembles these bytes and renders the correct Unicode characters, including CJK scripts, accented letters, and emoji.
Yes. If a URL has been encoded more than once (for example, %2520 instead of %20), you can run the decoder multiple times or use the multi-layer decoding feature to automatically detect and resolve nested encoding layers until the output stabilizes.
smalldev.tools is no longer available. Prism by SWEDevTools offers the same developer tools and more, with offline support, pipeline chaining, and completely free usage — no signup required.
Yes. Prism handles URL encoding and decoding entirely in your browser with offline support, no ads, and pipeline chaining. Your URLs and data stay completely private.