Query String Parser
Paste a query string or URL above to see the key and value pairs.
Paste a query string or a full URL and this tool splits it into clean key and value pairs, decoding percent-encoded characters as it goes. It handles a leading question mark, repeated keys, and spaces written as plus signs. You can also work the other way and build a correctly encoded query string from pairs you enter. Everything runs in your browser using the built in URLSearchParams, so nothing is sent anywhere.
How to use
- Pick Parse to read a query string, or Build to create one.
- In Parse mode, paste a query string or a full URL into the box.
- Read the decoded pairs and the JSON view, where repeated keys group into an array.
- In Build mode, add key and value rows, then copy the encoded query string.
- Use Copy to grab the JSON or the query string, or Reset to start over.
Examples
- Input: https://shop.example.com/search?q=hello+world&id=1&id=2 gives pairs q = hello world, id = 1, id = 2, and JSON {"q":"hello world","id":["1","2"]}.
- Input: ?utm_source=newsletter&utm_medium=email gives utm_source = newsletter and utm_medium = email.
- Build mode: keys name with value Quialo and q with value cats and dogs produces name=Quialo&q=cats+and+dogs.
FAQs
- Does it handle a leading question mark?
- Yes. A single leading question mark is removed before parsing, so both a bare query string and one copied straight from the address bar work the same way.
- Can I paste a whole URL?
- Yes. If the input contains a question mark, only the part after it is parsed. A URL with no query part is treated as having no pairs.
- How are repeated keys handled?
- Each repeat is kept as its own pair in the readable list so nothing is lost. In the JSON view, repeated keys collapse into an array of their values.
- What happens to percent-encoded values?
- They are decoded for the readable list and JSON. For example %20 becomes a space and %26 becomes an ampersand. A plus sign is also decoded as a space.
- Why does my space turn into a plus sign when building?
- Query strings encode spaces as plus signs by convention, which is what URLSearchParams produces. Servers decode it back to a space, so the round trip is correct.
- Is my data sent to a server?
- No. All parsing and building happen locally in your browser. Nothing you type leaves the page.
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