Query String Parser

Use this free query string parser to decode URL parameters, group repeated keys, or build an encoded query string from one key-value pair per line.

All tools

Research-backed assumptions Formula steps Examples included Private in-browser use

URL or query string

Parsed query parameters

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

3 parameters

Parameters: 3
Duplicate keys: 1
Output type: JSON object

URL query strings are useful for filters, tracking, and app state, but private tokens should not be shared in public URLs.

Formula steps

Extract the query part from a URL or raw query string.
Decode each parameter with URLSearchParams.
Group repeated keys so duplicate values stay visible.

How to use the query string parser

Choose Parse query when you have a URL or raw query string.
Choose Build query when you have one key=value pair per line.
Press Run query tool to decode parameters or create an encoded query string.
Check duplicate keys and avoid sharing private tokens in public URLs.

Common uses

Decode URL parameters while debugging filters, search pages, or app links.

Group repeated keys so duplicate values are easy to spot.

Build a correctly encoded query string from plain key-value lines.

Compare UTM links, search URLs, and app-state URLs before sharing.

Examples

Full URL https://example.com/?utm_source=newsletter&tag=a&tag=b

Decoded JSON with repeated tag values

Raw query name=Access+Free+Tools&tool=json

Readable key-value output

Build query utm_source=newsletter, utm_medium=email

?utm_source=newsletter&utm_medium=email

Frequently asked questions

Plain-language answers about when to use the tool, what it does with your inputs, what to double-check, and how privacy works.

When should I use the Query String Parser?

Use it when your task matches one of these common needs: Decode URL parameters while debugging filters, search pages, or app links. Group repeated keys so duplicate values are easy to spot. It works best when you already know the values, dates, units, or settings the page asks for.

What is the Query String Parser doing with my inputs?

In plain language: Parse mode extracts the query part and reads it with URLSearchParams. Build mode appends each key-value line with URLSearchParams encoding. The examples on the page are there so you can compare your inputs with a filled-out calculation before copying the answer.

What do the main Query String Parser inputs mean?

The main inputs are the values, text, dates, units, or settings the tool needs before it can work. Read each field label carefully, keep units consistent, and compare your entry with the examples if the answer looks strange.

How should I read the Query String Parser answer?

Read the output next to your original input. If the tool changes format, units, encoding, spacing, or capitalization, compare a small sample before copying the whole result into another app.

What should I double-check before trusting the answer?

Query strings can be logged, shared, or indexed. Do not place passwords, private tokens, or sensitive identifiers in public URLs. Also check that you used the right unit, date, scale, or mode because small input changes can change the result.

Does the site save what I enter?

No. The calculator runs in your browser tab. Your recent answers stay only on the page while you use it, and they are not sent to a server.