How to use the Query String Parser
1. Paste a query string (with or without the leading ?) to parse it into key-value pairs.
2. Or use the builder below to construct a query string from key-value entries.
3. Copy the parsed values or the built query string.
What is it?
Query strings are the part of a URL after the ? character. They encode parameters as key=value pairs separated by &. Values are percent-encoded (URL-encoded) to safely transmit special characters.
Parsing query strings manually is error-prone — special characters, encoding, and edge cases can cause bugs. Using a proper parser (like the browser's URLSearchParams API, which this tool uses) ensures correct handling of encoded characters, duplicate keys, and empty values.
Example
?name=Alice+Smith&age=30&city=New%20York
name = Alice Smith age = 30 city = New York
+ and %20 both decode to a space. The tool uses the browser's native URLSearchParams for accurate decoding.
Benefits
Parse URL query parameters into readable key-value pairs
No regex needed — extract every parameter from ?utm_source=email&campaign=spring into a clean, readable structure.
Debug tracking and UTM parameters in marketing URLs
See every UTM and custom parameter clearly without decoding percent-encoding or splitting strings manually.
Verify API request parameters before sending
Confirm the query string your client builds contains all required fields in the correct format before making the API call.
Parse query strings from server logs for traffic analysis
Extract parameter values from raw log entries to understand what users searched for, filtered, or configured.
Frequently asked questions
What is URL encoding in query strings?
Special characters (spaces, &, =, etc.) are replaced with % followed by their hex code. For example, space = %20, & = %26. This ensures the query string structure isn't broken by values.
Can a key appear multiple times?
Yes. Duplicate keys are valid in query strings. URLSearchParams.getAll() retrieves all values for a key. This tool shows each occurrence as a separate row.