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Query String Builder

Build an encoded URL query string from a JSON object, including repeated array parameters.

Free browser toolRuns in your browserNo sign-up
URL parameter builder

Build an encoded query string from structured JSON

Turn scalar values, arrays and nested objects into URLSearchParams-compatible output while preserving repeated array parameters.

Include ?

mode

63 B

input size

38 B

output size

Parameters as JSON object

63 characters

Encoded query string

38 characters

Null and undefined values are omitted. Arrays become repeated keys; nested objects are JSON-stringified into one value.

Private by design. Input is processed inside this browser tab and is not sent to ToolsOnDuty.

About the Query String Builder

Query String Builder is a focused browser-based utility. Build an encoded URL query string from a JSON object, including repeated array parameters.

The calculation runs locally in your browser, so the supplied value is not uploaded to ToolsOnDuty. The same capability is also available through the authenticated developer API.

Key features

  • Fast local processing with explicit validation
  • Copy-ready structured result
  • No account, upload or paid data provider required

How to use

  1. 1Enter a JSON object of parameter values.
  2. 2Choose any available conversion or formatting options.
  3. 3Run the tool and review an encoded query string.

Examples

Query String Builder example
Input: a JSON object of parameter values
Output: an encoded query string

Frequently asked questions

Is my input uploaded?
No. This website tool runs in your browser. Only the optional public API version sends input to the authenticated API route.
Can I use this in an application?
Yes. The Developers documentation lists the authenticated endpoint, request parameters and response example.
Should I verify the result?
Yes. Deterministic tools are designed for repeatable results, but format-specific or heuristic output should still be checked for your use case.

Continue your workflow

Open a related tool to prepare your files or refine the finished result.