Quick Answer
jq filters are the fastest way to pull fields out of a JSON API response in a bash script, but the syntax is easy to get subtly wrong — a missing -r leaves quotes on your value, a forgotten // turns a missing key into the literal null, and a select() with the wrong quoting matches nothing. This builder removes the guesswork. Paste a real response (or load a sample), then click through the actual structure to build the path; the tool shows the jq filter and the full curl … | jq command, and evaluates the filter against your JSON live so you can see exactly what comes out before you run it. It covers the patterns people actually script: nested field access, array indexing, iterating an array with a select() filter and projecting one field, defaults, and raw output. No data leaves your browser — parsing and evaluation happen client-side.
Does this run jq or send my JSON to a server?
No. The tool parses and evaluates your JSON entirely in the browser with JavaScript — nothing is uploaded and no jq binary is called remotely. The live preview mirrors what jq would output for the supported patterns, so you can paste a real (even sensitive) response safely and still see the result before running the command anywhere.
Why does my extracted value come out wrapped in quotes?
That is jq printing a JSON string, quotes included. Turn on raw output (-r) and the quotes disappear. This matters the moment the value goes into a shell variable, a filename, or a comparison: "web-01" with the quotes will not equal web-01, so almost any value headed into bash wants -r.
The filter looks right but the preview is empty — why?
Three common reasons: a select() filter matched no elements (jq would also output nothing), the path points at a key that does not exist in this response, or you used // empty as a default, which deliberately produces no output for a missing value. The note under the preview tells you which case you hit.
Does this support the entire jq language?
No — it builds the common extraction patterns that cover most API scripting: field and nested access, array indexing, iteration with select() and projection, // defaults, and -r. Advanced jq (reduce, string interpolation, arithmetic, if/then/else, custom functions) is out of scope; the jq manual is the reference for those.
Can I type a jq filter instead of clicking?
Yes. The filter box is editable. A filter inside the supported subset (a path, [] iteration, select(.key == value) with ==, !=, > or <, a | .key projection, or a // default) updates the clicked selection and the live preview as you type; the preview is checked against the real jq 1.8.1 binary. Anything else, such as length, map() or object construction, still goes into the generated curl | jq command, and the preview says it cannot evaluate it, so run that command with jq itself.
An operational script system + a 30-function shared library + a 52-page field guide. The production layer the free snippets don't cover.
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Type a filter or click through the JSON; both stay in sync.
curl -s "https://api.github.com/repos/cli/cli" | jq -r '.owner.login'
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Builds the common extraction patterns — field and nested access, array indexing, iteration with select() and projection, // defaults, and -r raw output. For the full language (reduce, string interpolation, math, conditionals) see the jq manual.