jq playground

This is the real jq — version 1.8.2, the C program compiled to WebAssembly by jq-wasm — not a re-implementation, so filters, error messages and edge cases behave exactly as they do in your terminal. Paste JSON on the left, write a filter on the right, and the output follows as you type.

For formatting, validating, browsing JSON as a tree, JSONPath and diffs, use the JSON workbench. To clean and reshape tables (CSV, Parquet) with SQL, use the data wrangler.

How to use it

Input. Pick a sample — a GitHub repository-search response, kubectl get pods -o json, a log file of JSON lines, or a nested application config — paste your own, or Open file…. Several values one after another (JSON lines) are fine: jq runs the filter once per value, as it does on the command line. Format pretty-prints one document or tidies JSON lines.

Filter. The output updates a quarter of a second after you stop typing (Cmd/Ctrl + Enter runs at once). Compile errors and runtime errors are shown in red exactly as jq prints them, with the caret under the problem; output produced before a runtime error is kept, as in the terminal. Messages that are not errors (debug, stderr) are shown in grey. A filter that runs for more than four seconds (repeat(1) without a limit) is stopped and jq restarted.

Flags. -r raw strings, -j raw with no newlines, -c compact, -s slurp all inputs into an array, -n null input (with input / inputs to read), -R raw input lines, -S sorted keys, --tab. + --arg adds a variable: --arg passes a string, --argjson a JSON value; both appear as $name and in $ARGS.named.

Examples. Fifty-two filters grouped by task — select and map, group_by and sorting, reduce and foreach, paths, to_entries / with_entries, @csv @tsv @base64 @sh @uri, string interpolation and regexes, recursive descent .., limit / first / until, --arg and --argjson, slurp / -n / -R, and updates, del, def and try. One click loads the example’s data, flags and filter, with a note on what it shows.

Step through the pipe. Lists every top-level stage of the filter with the output of the program up to that point, so you can see where a long pipeline goes wrong. Pipes inside brackets, strings, if … end and def … ; are not split, |= is not a pipe, and a … as $x binding is joined to the stage that uses it.

Command line. The same run as a shell command — jq -rc --arg ns kube-system '…' pods.json — quoted for a POSIX shell, optionally with the input inline as a here-document.

History keeps filters that ran cleanly, in this browser only. Share link puts the filter, flags, variables and input in the URL (for a sample, just its name); a large input makes a long link.

Differences from jq in a terminal

There is no environment and no file system: $ENV and env describe the WebAssembly sandbox, input_filename is /dev/stdin, and --slurpfile, --rawfile, -f, import of modules on disk and --seq / colour output are not offered. Pass values with --arg / --argjson.
leaf_paths was removed in jq 1.8 — use paths(scalars). Other 1.7 → 1.8 changes apply too (for example ltrimstr on a non-string is now an error).

Browser support

Any current browser with WebAssembly and module workers (Chrome, Edge, Firefox 114+, Safari 15+). jq runs in a Web Worker, so a slow filter never freezes the page. It does not need cross-origin isolation or SharedArrayBuffer.

Privacy

jq’s WebAssembly module (about 1 MB, MIT licence) is downloaded once from cdn.jsdelivr.net and cached by your browser. Your JSON and filters are processed on your device and never sent anywhere; the input, filter and history are kept in this browser’s local storage. A share link contains whatever input you share with it.