Query String Builder

Build URL query strings from JSON parameters.

What this tool does

Convert JSON key-value pairs into URL query strings for API requests, tracking links, and integration tests.

Tool interface

Input

Output

Example input

{"utm_source":"newsletter","id":42,"tag":["a","b"]}

Example output

utm_source=newsletter&id=42&tag=a&tag=b

Step-by-step instructions

  1. Paste a JSON object with query parameter fields.
  2. Click Transform to build the query string.
  3. Copy the output and append it to your URL.

Common use cases

  • Debugging request payloads and encoded values quickly.
  • Generating development data and identifiers.
  • Validating text, URLs, timestamps, and structured content.

Speeds up API testing and tracking URL creation when you need correctly encoded query parameters quickly.

Common mistakes to avoid

  • Providing arrays at the top level instead of an object.
  • Assuming null values are included in output.
  • Forgetting to parse duplicate keys as repeated parameters.

Frequently Asked Questions

Can Query String Builder handle array values?

Yes. Arrays are emitted as repeated key=value pairs.

Are values URL-encoded?

Yes. Output is encoded for query-string compatibility.

Does Query String Builder support nested objects?

Nested objects should be flattened before building query strings.

What input format does Query String Builder expect?

Use the format shown in the example input on this page.

What does Query String Builder output?

It returns transformed output that you can copy directly from the result panel.

Why might Query String Builder return an error?

A common issue is: Providing arrays at the top level instead of an object.

Does Query String Builder run in the browser?

Yes. Transformations are designed for in-browser usage so you can test and iterate quickly.

Can I copy or download results from Query String Builder?

Yes. You can copy transformed output directly from the tool.

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