Prettify vs jqplay: jq Playground Alternative

At a glance

Both tools run jq on your device and show the output next to your query. The core difference is the engine: the jq playground runs real jq, and Prettify runs a custom engine. Where the playground site is silent, this page says so.

• Local processing and privacy: Prettify runs queries on your device and does not send them anywhere; the jq playground processes queries and HTTP requests locally in your browser and sends a snippet to its server only when you share it.
• Formats: Prettify opens JSON, JSONL, YAML, CSV and TSV, XML, Mermaid, Markdown, MDX, and HTML, and jq also works on the parsed data of YAML; the jq playground takes JSON, pasted or fetched from an HTTP URL.
• Views: Prettify shows the document as a Tree, Raw text, a Table, or a Pro node Diagram; the jq playground has Query, Options, and Output panels.
• Query engines: Prettify has a custom jq engine with 192 builtin names, plus SQL for CSV and XPath for XML, all Pro; the jq playground runs real jq compiled to WebAssembly.
• Diff: Prettify has Diff and Compare in Pro; the jq playground's site does not mention a diff tool.
• Share links: Prettify has inline links that carry the document in the URL, and Pro short links; the jq playground gives a shared snippet a unique URL generated on its server.
• Platforms: Prettify runs on the web, as an installable PWA, and as a native app for macOS, Windows, and Linux; the jq playground is a web app with a public API.
• Pricing: Prettify has a free tier, and its jq panel is a Pro tool at US$19.99 once, with one free try per day; the jq playground is free with no pricing listed.

Where the jq playground is strong

The playground is the reference choice: it is the jq project itself, in your browser. These are its main strengths.

• It runs real jq, the reference implementation, so the output matches the jq command.
• It is free, and no paywall or pricing appears anywhere on the site.
• It is open source under the MIT license, and it belongs to the jqlang organization.
• It can fetch JSON from an HTTP URL as input, and a public API runs queries on the server.
• A shared snippet gets its own URL that you can send to a colleague.

Where Prettify is different

Prettify puts jq inside an editor that already holds your document. You do not copy data between a viewer and a playground. These facts come from the Prettify docs and source.

• The engine is custom, not a WebAssembly port. It matches jq 1.7 for the features its docs list, and the docs name each difference.
• The query updates as you type. The Result pane shows a stream with a count, such as 2 results.
• Apply replaces the document with the result after you confirm, and History can bring back the earlier version.
• Quick buttons, a Guide of example expressions, and a Wizard help you build a query.
• SQL runs on CSV and TSV files, and XPath runs on XML, in the same app.
• Large JSON numbers stay exact when a query only reads or copies them.
• Load from URL fetches a document by address, up to 100 MB. On the web, you approve a public proxy before Prettify uses one.

Differences from the jq command

If your query must match the jq command exactly, read this list first. A query has one input document, so inputs produces nothing. The env and $ENV values are empty objects, because a browser has no process environment.

Deep recursion in your own functions ends with an error, where jq has no such limit. A field name used on an array, such as .items.price, maps over the elements, and jq raises an error. Number output follows JSON, so infinite prints as null.

How to try the same job in Prettify

The box at the top of this page checks and formats your JSON. It does not run jq filters. The jq panel is in the editor. It is a Pro tool, and free users get one free try of it per day.

1. Paste your JSON into the box at the top of this page, or select Try an example. The box takes up to 512 KB.
2. Read the result panel. It shows a summary, or the line and column of the first error.
3. Select Open in full editor. If the JSON has an error, the button reads Fix it in the editor.
4. In the editor toolbar, select jq in the Transform group. You can also press Cmd+K (Ctrl+K on Windows and Linux) and run Query / Transform.
5. Type a jq expression. The Source pane shows your document and the Result pane shows the output.
6. Select Copy to copy the output, or select Apply and confirm to replace the document.

Which one to choose

The right tool depends on how exact your jq must be and what else you do with the data. Many people use both: the playground to confirm real jq behavior, and Prettify to explore and reshape a document.

• Choose the jq playground if the query will run in the jq command, and the output must match it exactly.
• Choose the jq playground if you want a free, open source tool with a shareable snippet URL.
• Choose Prettify if you want to browse the document as a tree or a table before you write a query.
• Choose Prettify if you also query CSV with SQL or XML with XPath.
• Choose Prettify if you want to apply the result back to the document, or work in a desktop app.

Frequently asked questions

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