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Need to quickly decode URL parameters and turn a messy query string into something readable? This free query string decode tool lets you paste any URL or query string and instantly see the decoded values — perfect for developers, SEOs, QA testers, and marketers who work with URLs every day.
A query string is the part of a URL that comes after a ?, often used to pass data between pages or track campaigns. For example:
https://example.com/page?name=John+Doe&utm_source=newsletter&utm_campaign=spring_sale
Those values are often URL encoded so that special characters (spaces, &, =, /, etc.) can safely travel over the web. Encoding replaces them with patterns like %20 or +, which makes the URL machine-friendly but hard for humans to read
This tool helps you:
utm_source, ref, id).%xx codes and + signs back into normal characters.The Coderstool Query String Decode page is a simple online utility that:
utm_source=newsletter&name=John+Doe).%20, %2F, %3D) back to their original ASCII characters.+ symbols into spaces so names and phrases become readable again.If you’ve ever copied a long URL from analytics, email software, or an app and needed to decode query string values to understand what’s going on, this tool does the heavy lifting for you.
This is ideal when you want to decode URL parameters like utm_source, utm_medium, utm_campaign, affiliate IDs, or tracking tokens.
Sometimes you only have the query portion, such as:
name=John+Doe&city=New+York&message=Hello%2C+world%21
name=John Doe
city=New York
message=Hello, world!
Behind the scenes, the tool performs a query string decode by reversing the percent encoding and + substitutions used in standard URL encoding.
After you decode query string data:
Marketers and SEOs often work with URLs that look like this:
https://example.com/?utm_source=newsletter&utm_medium=email&utm_campaign=Spring+Sale+2025
Use the tool to decode URL params so you can quickly verify:
utm_source and utm_medium.Shorteners and redirects often hide long query strings behind a short URL. After expanding the link, you can:
Developers and QA testers frequently need to inspect query strings in:
Query string decode helps you confirm:
When reproducing bugs:
When you encode a query string, you convert unsafe characters into an encoded form. When you decode, you do the reverse
| Character | Encoded form |
|---|---|
| space | + or %20 |
, | %2C |
/ | %2F |
? | %3F |
& | %26 |
= | %3D |
The Query String Decode tool takes those encoded values and returns them to their original readable form, making it much easier to reason about URLs.
For the opposite operation (turning readable text into safely encoded URLs), use the companion Query String Encode tool.
While this page focuses on the online query string decode tool, you may sometimes need to decode values directly in code:
decodeURIComponent(value)urldecode($value) or rawurldecode($value)Request.QueryString["key"] when you access it.The online tool is still useful when you just want to inspect a URL quickly without opening an editor or console.
Paste the full URL (or just the query part) into the Coderstool Query String Decode page and click Decode. The tool will automatically decode URL parameters, converting %xx sequences and + signs back into spaces and readable characters.
Yes. You can paste:
?Hello%2C+world%21The tool will apply query string decode logic to whatever you provide.
Coderstool tools are designed as simple, browser-based utilities. You use them directly in your browser; the intent is to process data quickly, not to store or track your inputs. For sensitive URLs, avoid sharing them and use the tool directly in a secure browser session.
A generic URL decoder focuses on decoding any URL-encoded text. The Query String Decode page is specifically optimized for decoding URL parameters and query strings, making it more convenient when you work with GET variables, tracking URLs, and SEO links. It’s part of Coderstool’s broader Encode Decode Tools collection for developers and SEOs.
To go further with URL and text utilities, try these related tools:
Use these together to build a smooth workflow for decoding URL params, cleaning URLs, and transforming data for your projects.
Code generation, like drinking alcohol, is good in moderation.
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