Run jq on JSON

The engine is jaq, a pure-Rust implementation of the jq language, loaded with the jq standard library (map, select, group_by, sort_by, add, unique, and friends). Filters that work in jq almost always work here. One visible difference: jaq emits object keys in sorted order rather than insertion order.

A jq filter produces a stream of values — zero, one, or many — and each value is shown on its own line. .[] over a three-element array yields three outputs. To collapse a stream into a single value, wrap it in [...] (e.g. [.[] | .name]) or use map(...).

Four distinct cases: invalid JSON input (with the parser's position message), a jq parse error (e.g. a trailing |), a compile error (an unknown function name), and runtime errors such as adding a number to a string. An empty filter is also rejected, so a blank query never silently returns nothing.

No. jaq is compiled to WebAssembly and evaluates the filter entirely in your tab — there is no server-side jq process and nothing is transmitted or logged.