URL Query String Parser

What Is a URL Query String?

Every time you search Google, filter an e-commerce site, or click a tracking link in an email, you're using a URL with a query string. A query string is the part of a URL that comes after the ? character and contains key-value pairs separated by &.

Example URL:

https://shop.example.com/results?category=shoes&color=red&size=42&sort=price_asc&page=2

Breaking this down:

• ? — marks the start of the query string
• category=shoes — key: category, value: shoes
• color=red — key: color, value: red
• size=42 — key: size, value: 42
• sort=price_asc — key: sort, value: price_asc
• page=2 — key: page, value: 2

Our URL Query String Parser takes any URL you paste in and instantly displays every parameter in a clean, readable table.

Why Query Strings Get Messy

In practice, query strings are rarely this clean. Real-world URLs often contain:

URL Encoding: Spaces, special characters, and non-ASCII text must be percent-encoded. A space becomes %20, a + becomes %2B, and @ becomes %40. This makes raw URLs unreadable.

https://api.example.com/search?q=iPhone%2015%20Pro%20%2B%20case&lang=en-US

Base64 and JWT tokens in queries: Authentication tokens passed via URL can be hundreds of characters long.

Nested objects: Some frameworks serialize nested JavaScript objects as query strings:

filter[price][min]=10&filter[price][max]=500&filter[brand][]=Nike&filter[brand][]=Adidas

Array parameters: The same key repeated multiple times.

Our parser handles all of these cases and displays the decoded human-readable values alongside the raw encoded versions.

Real-World Use Cases

API Debugging: When testing a third-party API, the endpoint URL often contains authentication tokens, filter parameters, and pagination. Paste the full URL to instantly see what parameters are being sent without counting characters manually.

Affiliate & Tracking Links: Marketing URLs contain utm_source, utm_medium, utm_campaign, and dozens of other tracking parameters. Parse any link to see exactly what data it sends back to analytics systems.

E-commerce Filtering: Filter and sort state is often stored entirely in the URL query string. Parsing it helps understand how a platform's filter system works.

Redirect Debugging: SAML SSO, OAuth callbacks, and payment gateway redirects carry encoded payloads in their query strings. Decoding these is essential for debugging authentication flows.

Web Scraping & Data Analysis: When analyzing scraped URLs, extracting specific parameters (like product IDs or category codes) from hundreds of URLs is much easier with a structured parser.

How URL Encoding Works

Before a query string travels over the internet, it must be URL-encoded (also called percent-encoding). Any character that isn't a letter, number, -, _, ., or ~ must be encoded as a % followed by its two-digit hexadecimal ASCII code.

Our tool shows you both the raw encoded value and the decoded human-readable value side by side.

How to Use the Parser

1. Paste the full URL — including the https:// scheme and everything after.
2. The tool instantly splits the URL into: protocol, hostname, path, and query parameters.
3. Each parameter is displayed in a table with key, raw value, and decoded value.
4. Use the copy button next to any value to grab it in one click.
5. For API URLs with encoded JSON in the query, the decoded value will show the readable JSON.

Best Practices for Developers

Never pass sensitive data in query strings. Query strings appear in server logs, browser history, and Referer headers. Passwords, API keys, and personal data should go in the request body or headers instead.

Validate and sanitize all query parameters. Malicious users can manipulate query string values. Always validate types and ranges server-side — never trust client-supplied query parameters.

Use consistent parameter naming. Stick to either snake_case (sort_by) or camelCase (sortBy) within your application. Mixing styles leads to maintenance headaches.

Prefer arrays over duplicated keys. Both tags[]=a&tags[]=b and tags=a&tags=b work, but check what your framework expects and be consistent.