Curl Pretty Print JSON: jq, python, formatarc CLI, and Browser Options

TL;DR — the one-liner

If jq is already installed, this is all you need:

curl -s https://api.example.com/users/1 | jq .

No jq? Use Python, which ships with most systems:

curl -s https://api.example.com/users/1 | python3 -m json.tool

Prefer a browser? Paste the response into FormatArc JSON Formatter — no install, works offline after the first load. The rest of this guide compares all four options so you can pick the right one for each situation.

Why curl output is hard to read

When you hit an API with curl, the JSON response comes back as a single line.

curl -s https://api.example.com/users/1

{"id":1,"name":"Tanaka","email":"tanaka@example.com","address":{"city":"Tokyo","zip":"100-0001"},"roles":["admin","editor"]}

No line breaks, no indentation. As nesting increases, this becomes impossible to scan. Here are four ways to turn that wall of text into readable JSON.

Pretty-print with jq

jq is the most popular command-line JSON processor.

Installing jq

# macOS
brew install jq

# Ubuntu / Debian
sudo apt install jq

# Windows (Chocolatey)
choco install jq

Basic usage

Pipe curl output into jq with a dot filter.

curl -s https://api.example.com/users/1 | jq .

{
  "id": 1,
  "name": "Tanaka",
  "email": "tanaka@example.com",
  "address": {
    "city": "Tokyo",
    "zip": "100-0001"
  },
  "roles": [
    "admin",
    "editor"
  ]
}

The -s flag silences curl's progress bar so only JSON reaches jq.

Useful filters

jq does more than pretty-printing. It can extract specific fields from the response.

Extract a single key:

curl -s https://api.example.com/users/1 | jq '.name'

"Tanaka"

Access nested keys with dot notation:

curl -s https://api.example.com/users/1 | jq '.address.city'

"Tokyo"

Pull a field from every element in an array:

curl -s https://api.example.com/users | jq '.[].name'

"Tanaka"
"Suzuki"
"Sato"

Filter elements by condition with select:

curl -s https://api.example.com/users | jq '.[] | select(.roles[] == "admin")'

Pretty-print response headers and JSON together (curl -i)

The -s examples above drop everything except the response body. When you debug an API and want to see both the headers and the body, you reach for curl -i. The catch: piping curl -i | jq . always fails, because the header block at the top of the stream is not JSON.

curl -is https://api.example.com/users/1 | jq .
# parse error: Invalid numeric literal at line 1, column 9

You need to keep the headers visible but route only the JSON body into jq.

Stream split: headers to stderr, body to stdout

curl -D <file> writes the response headers to the file you point at. Aim it at /dev/stderr and the headers print to the terminal while stdout keeps just the body — ready for jq.

curl -sSD /dev/stderr https://api.example.com/users/1 | jq .

HTTP/2 200
content-type: application/json
cache-control: no-store
date: Mon, 19 May 2026 09:30:00 GMT

{
  "id": 1,
  "name": "Tanaka",
  ...
}

The headers reach the terminal but never enter the pipe, so jq sees only valid JSON. On Windows PowerShell, /dev/stderr does not exist — write to a file and cat it afterward (see the file-split pattern below).

File split: save headers and body separately

When you want to keep both for later inspection (e.g. saving a failed request for triage), split into two files with -D and -o.

curl -sSD head.txt -o body.json https://api.example.com/users/1
cat head.txt
jq . body.json

This works identically on macOS, Linux, and Windows (any shell). Use it when you also want to grep the headers later, or attach them to a bug report.

Make it a permanent alias

Most of the time you want one short command. Add this to your ~/.bashrc or ~/.zshrc:

alias curl-json='curl -sSD /dev/stderr'
curl-json-format() { curl-json "$@" | jq .; }

Now curl-json-format https://api.example.com/users/1 prints headers to the terminal and pretty JSON below. The function name is intentionally explicit so it does not collide with anything else in your shell history.

curl 7.82+ --json shortcut (request side)

The flip side of pretty-printing a response is sending JSON in a request. Since curl 7.82 (March 2022), the --json shortcut sets Content-Type: application/json, Accept: application/json, and --data in one flag.

curl --json '{"name":"alice"}' https://api.example.com/users

It does not pretty-print the response on its own — pipe it into jq or one of the methods below to format the body. But it removes the three usual flags from request examples, so combining --json for the request with curl-json-format for the response gives a clean two-step pattern for any REST API.

Pretty-print with Python json.tool

If Python is already installed, you don't need any extra tools. The standard library includes json.tool.

curl -s https://api.example.com/users/1 | python3 -m json.tool

{
    "id": 1,
    "name": "Tanaka",
    "email": "tanaka@example.com",
    "address": {
        "city": "Tokyo",
        "zip": "100-0001"
    },
    "roles": [
        "admin",
        "editor"
    ]
}

It doesn't have jq's filtering capabilities, but for quick formatting it does the job. On systems with Python 2 only, use python instead of python3.

Pretty-print with formatarc CLI

Installation and usage

formatarc runs instantly via npx with no installation required.

curl -s https://api.example.com/users/1 | npx formatarc json-format

{
  "id": 1,
  "name": "Tanaka",
  "email": "tanaka@example.com",
  "address": {
    "city": "Tokyo",
    "zip": "100-0001"
  },
  "roles": [
    "admin",
    "editor"
  ]
}

For frequent use, install it globally to skip the npx startup time.

npm install -g formatarc
curl -s https://api.example.com/users/1 | formatarc json-format

Pipe to YAML or CSV

formatarc can also convert the JSON output to YAML or CSV in the same pipeline.

curl -s https://api.example.com/users/1 | npx formatarc json-to-yaml

id: 1
name: Tanaka
email: tanaka@example.com
address:
  city: Tokyo
  zip: "100-0001"
roles:
  - admin
  - editor

See the formatarc CLI guide for the full list of commands and options.

Format in the browser

Using FormatArc JSON Formatter

If you prefer not to use the command line, copy the curl output and paste it into JSON Formatter.

1. Copy the curl response
2. Open FormatArc JSON Formatter
3. Paste into the left text area
4. Click "Format"

The formatted result can be copied or converted to YAML / CSV directly from the tool.

Handling parse errors

If the JSON contains syntax errors, formatting will fail. Common causes and fixes are covered in How to Fix JSON Parse Errors.

If the API response contains // or /* */ comments and jq or json.tool fails to parse it, the payload may be JSONC or JSON5. See How to Add Comments to JSON for the working alternatives.

If you want a JSON URL to be auto-formatted the moment you open it in a tab, a Chrome extension is an alternative to curl. See Best Chrome JSON Formatter Extensions Compared.

Which method to choose

Using jq for everyday work and adding formatarc CLI when you need format conversion is an efficient combination.

Related articles

• JSON Formatting Tips
• formatarc CLI Guide
• How to Fix JSON Parse Errors
• JSON Syntax Guide
• How to Add Comments to JSON
• Best Chrome JSON Formatter Extensions Compared

Summary

This article covered four ways to pretty-print JSON from curl: jq, Python's json.tool, formatarc CLI, and browser-based tools. jq is the most capable option with its filtering features, and the curl -sSD /dev/stderr | jq . pattern keeps response headers visible without breaking the parse. Python's json.tool requires no installation on most systems. formatarc CLI adds YAML and CSV conversion to the pipeline. For a visual approach, try FormatArc JSON Formatter.