Query String to JSON Converter
Convert a URL's query parameters to JSON, and JSON back to a query string.
Three steps, no reading required.
Paste your input
Drop text, code, or data into the input pane — from an API response, a file, anywhere.
Pick a mode
Toggle the modes above the output. The result updates instantly as you type.
Copy the result
Grab the output with Copy or Download, or fix the error shown if the input is invalid.
Try it with a sample.
name=Ada&role=admin&role=dev&filter[status]=open&tags[]=a&tags[]=b
Repeated keys overwrite each other
- Keeps only the last role=b
- Flat output, no nesting
- Uploads URLs that may carry tokens
Nothing lost on the way in
- Repeated keys and [] suffixes collapse into arrays
- Bracket notation like filter[status] parses into nested objects
- Decodes %-encoding and +; converts back too
Questions worth answering upfront.
No. Conversion runs entirely in your browser. Your query strings are never uploaded, stored, or logged.
Repeated keys (role=a&role=b) and keys with a [] suffix collapse into a JSON array, so nothing is lost.
Yes. Bracket notation like filter[status] or a[b][c] parses into nested JSON objects, and JSON objects serialize back using the same notation.
Yes. Percent-encoding and + are decoded on the way in, and values are percent-encoded on the way out. Values stay strings so conversion round-trips.
Yes. Every tool on DevUtilsNow is free to use with no account required.
Yes. Paste the whole address, such as https://example.com/page?a=1&b=2, and only the part after the ? is parsed. Any #fragment at the end is ignored.
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Guides that pair with this tool
How to Convert a Query String to JSON (and Back)
Parse a URL query string into JSON and serialize JSON back — how repeated keys, bracket notation, and encoding are handled.
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