Query String Parser & Builder
Parse a URL query string into key/value pairs or build one.
- Reading time:
- 2 min
- Last updated:
- Price:
- Free, no signup
Type or paste text to see the result.
What the Query String Parser & Builder does
Parse complex URL query parameters into readable JSON or format key-value pairs back into encoded query strings.
Easily inspect tracking parameters, API query payloads, UTM tags, and deep-link arguments without manual string manipulation.
Why the Query String Parser & Builder is useful
Long URLs with multiple encoded parameters, arrays, and special characters are hard to read and prone to manual syntax errors.
Parsing query strings into structured data helps developers, marketers, and QA testers verify tracking, debug APIs, and construct valid endpoints.
Also known as: query string parser, query string builder, url parameter parser, free query string parser & builder, online query string parser & builder, query string parser & builder online free, query string parser & builder tool.
How to use the Query String Parser & Builder
- 1
Paste URL or Parameter String
Enter a complete URL or a raw query string beginning with '?' or parameter pairs.
- 2
View Parsed Key-Value Pairs
Inspect decoded keys and values in an organized tabular or JSON representation.
- 3
Edit or Rebuild Query String
Add, remove, or modify parameters, then generate the correctly encoded output URL.
Key features
- Automatic URL decoding for percent-encoded characters, spaces, and symbols
- Two-way conversion: URL to JSON and JSON/Form back to valid query string
- Handles duplicate keys, bracketed array notations, and nested structures
- One-click copy for parsed JSON objects or encoded query URLs
Benefits
- Instantly debug complex marketing URLs with numerous UTM and tracking parameters
- Eliminates encoding mistakes like unescaped ampersands or malformed hash fragments
- Speeds up API request drafting and frontend routing debugging
Real-life use cases
Marketing Attribution QA
Verify utm_source, utm_medium, utm_campaign, and gclid parameters on ad landing pages.
REST API Development
Inspect and construct filter, sorting, and pagination parameters for backend API calls.
Tips for the best results
- Remember that spaces in URLs can be encoded as either '%20' or '+' depending on the implementation.
- Strip sensitive tokens, API secrets, or passwords before sharing parsed query strings.
- Ensure parameter keys are case-sensitive matching what your backend application expects.
Conclusion
Inspecting and constructing URL parameters with a dedicated parser eliminates encoding bugs and ensures accurate tracking and API communications.
Frequently asked questions
What is a query string?
- A query string is the part of a URL following the question mark (?) containing key-value pairs separated by ampersands (&).
How are special characters handled in query strings?
- They are percent-encoded (URL encoded), so characters like spaces become %20 and ampersands become %26.
Can a query string contain multiple values for the same key?
- Yes, repeated keys (e.g., tag=seo&tag=web) or bracketed keys (tag[]=seo) are commonly used to represent lists.
Does this tool work completely in the browser?
- Yes, all parsing and encoding happens client-side; no URLs or parameters are logged or sent to external servers.
What is the difference between encodeURI and encodeURIComponent?
- encodeURIComponent encodes all special characters including ?, =, and &, making it ideal for individual parameter values.
Can I convert query parameters directly into a JavaScript object?
- Yes, the tool outputs structured JSON matching standard JavaScript object conventions.
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Browse the full tools directory, filter by category, or read guides on the Text Tools Hub blog.