jq: readable JSON in the terminal and one-expression value extraction

JSON is everywhere — API responses, config files, logs — and it almost always arrives as an unreadable single-line mush. Anyone who wants to read it pastes it into an online formatter (sending the data who-knows-where) or hunts through it by eye. The jq tool solves this right in the terminal: it formats, indents, and colors JSON with a single command. And that's just the start — jq is also a query language that pulls a specific value, a list of fields, or a filtered subset out of JSON, no script required.

How to do it

1. Install jq: on Windows winget install jqlang.jq, on Mac brew install jq, on Linux it's usually in the system packages (apt install jq).
2. The basics — formatting: jq . file.json prints the file indented and colored. The dot means "the whole input, unchanged." jq most often gets piped straight after curl: curl -s https://api.example.com/users | jq .
3. Extracting a value: jq '.name' returns the name field, jq '.address.city' a nested value, jq '.[0]' the first element of an array.
4. Iterating over an array: jq '.items[].name' prints the names of every item in the items array. Combined with selecting multiple fields: jq '.items[] | {name, price}' turns each item into a small object with just those two fields.
5. If you're not sure about an expression, build it up gradually — start with a dot and add pieces. And for a more complex query ("pick items over a hundred and sort by name"), AI will reliably suggest one for you these days, similar to the tip on regex without the learning curve — put the jq expression in the prompt along with a sample of the data.

A typical scenario

A developer is debugging an integration with a shipping carrier's API. The response is eight kilobytes on a single line, and all she cares about is the shipment status and the time of the last update. Instead of pasting it into a browser, she writes curl -s ... | jq '.shipment | {status, updated_at}' and sees exactly those two values, cleanly. When she needs the same thing for fifty shipments, she just tweaks the expression to iterate over the array — and gets a table that would otherwise take half an hour to build with a script. And the sensitive data never left her machine, which online formatters can never quite guarantee.

If jq isn't installed, at least a built-in substitute can format: python3 -m json.tool file.json indents JSON with no installation at all. It can't query, though — for pulling out values, jq is irreplaceable.

What you get out of it

Reading JSON stops hurting: formatting is a single command away, and you pull out a specific value with an expression instead of your eyes. No more pasting work data into web tools. And because jq chains with curl and other commands into pipelines, it becomes a building block for one-off analysis as well as scripts that would otherwise require Python.