Query Params Viewer

Break down URL query params — nested encoded params expand automatically

English
Use with AI npx -y github:Deguang/query-params-viewer

Supports full URLs, hash routes (e.g. #/path?a=1), or bare query strings (e.g. a=1&b=2). Press Enter to parse.

No URL parsed yet. Paste a link, or click "Example" to see it in action.

About Query Params Viewer

A URL query string is the part after the ? — a list of key=value pairs joined by &, such as ?q=shoes&page=2. Query Params Viewer decodes that string and lays every parameter out in a table: it URL-decodes each value, flags duplicate keys, pretty-prints JSON, and expands parameters that are themselves an encoded URL. Everything runs in your browser — nothing is uploaded.

Frequently asked questions

What is a URL query parameter?
It is a key=value pair in the part of a URL after the ?. Multiple parameters are separated by &, for example ?q=shoes&page=2&sort=asc. The same key may appear more than once.
How do I decode a query string?
Paste a full URL, a bare a=1&b=2 string, or a #/path?a=1 hash route into the box and press Parse. Each value is URL-decoded — %20 becomes a space, %3D becomes = — and shown in a table with its detected type.
Is my URL sent to a server?
No. Parsing, editing, comparing and share-link generation all run in your browser; the URL never leaves your device. Share links carry their state in the # fragment, which browsers never send to the server.
What happens with duplicate keys?
Every occurrence is kept and shown on its own row, tagged like 1/2 and 2/2. This matches how URLSearchParams and most servers read repeated keys, so you see values a simpler parser would silently drop.
Can it read a URL nested inside a parameter?
Yes. When a value is itself an encoded URL or query string — such as redirect=https%3A%2F%2F…%3Ftoken%3Dabc — you can expand it to inspect its inner keys and values, up to three levels deep.
Can an AI assistant use this tool?
Yes. The same parser is also packaged as an MCP server, so an assistant in any MCP-capable client — Claude, Cursor, Cline and others — can break down or diff a URL for you without anyone opening this page. It offers two tools — parse_url and compare_urls — and runs on your own machine, so URLs stay on your device just as they do here. Setup instructions live in the mcp-server directory of the repository.