About this utility
How to use Query String Parser & Builder
Parse duplicate query parameters into JSON or build a query string from a JSON object.
What to provide
Parse mode accepts a query with repeated keys such as ?a=1 followed by a=2, or a complete URL. Build mode accepts a JSON object; array values become repeated keys.
- Paste, type, or drag and drop a supported text file into the input area.
- Choose the options that match your intended result.
- Select “Run tool” or press Ctrl/Command + Enter, then copy, download, or move the result back into the first input for another pass.
What the result means
A JSON parameter map or a percent-encoded query string.
Privacy and safety
This utility is loaded as browser code and processes your input only in this tab. OmniCastConverter has no upload endpoint and never stores your content, filenames, tokens, or secrets. Generated markup and code are shown as inert text and are never executed.
Limitations
- Parsing preserves duplicate values as arrays but cannot recover the original percent-escape spelling or parameter ordering after JSON editing.
Try the included example
Select “Load example” at any time to restore this tested sample.
?q=coffee&q=cake&page=2&empty=