What if I only paste the JSON body, without headers?

That works too. If no blank line separating a header block from a body is found, the entire input is treated as the JSON body and reformatted directly, same as a plain JSON formatter.

Does it touch the headers at all?

No. If a header block is detected, it's left exactly as pasted (just trimmed of surrounding whitespace); only the JSON body below it gets re-indented.

What happens if the body isn't valid JSON?

You'll get an error describing what went wrong. Many APIs return HTML error pages or plain text under non-2xx statuses, and those aren't reformattable as JSON, so paste just the body's own content if you're not sure it's JSON.

API Response Formatter - Pretty-Print an API Response Online

Overview

Introduction

API responses copied from a terminal or a browser's network panel are often a single unbroken line of JSON, sometimes with headers stacked on top, that's painful to read as-is.

This tool reformats just the JSON body with proper indentation, leaving any header block above it untouched, entirely in your browser.

What Is API Response Formatter?

A pretty-printer specialized for pasted API responses: it recognizes the header-block-then-body shape curl -i and browser dev tools produce, and only reformats the JSON part.

It's part of this site's API Tools collection and runs entirely client-side.

How API Response Formatter Works

The input is scanned for the first blank line, the conventional separator between an HTTP response's headers and its body; everything after that point is treated as the body.

The body is parsed as JSON and re-serialized with 2-space indentation; any header block found above it is reattached unchanged.

When To Use API Response Formatter

Use it right after copying a response out of curl -i, Postman's console, or a browser's network tab, before you read through it.

It's also just a convenient JSON formatter when you paste a bare, unindented JSON body with no headers at all.

Often used alongside jq Playground.

Features

Advantages

Handles both a bare JSON body and a full raw-response paste without needing to strip headers first.
Leaves headers exactly as pasted, so nothing about the response's metadata gets altered or reordered.

Limitations

Only reformats JSON bodies; XML, HTML, or plain-text response bodies are passed through as an error, not reformatted.
Relies on a blank line to detect a header block; a response paste missing that blank line is treated as a bare body instead.

Examples

Formatting a bare JSON body

Input

{"id":1,"status":"ok"}

Output

{
  "id": 1,
  "status": "ok"
}

No header block is detected, so the whole input is parsed and reformatted as JSON.

Formatting a full curl -i response

Input

HTTP/1.1 200 OK
content-type: application/json

{"id":1,"status":"ok"}

Output

HTTP/1.1 200 OK
content-type: application/json

{
  "id": 1,
  "status": "ok"
}

The header block above the blank line is kept as-is; only the JSON body below it is re-indented.

Best Practices & Notes

Best Practices

Copy responses with curl -i (or your API client's "copy raw response" option) if you want the headers preserved alongside the formatted body.
Strip everything before the header block (like a shell prompt or command echo) if formatting fails; stray leading text confuses the header/body split.
Use the JQ Playground afterward if you need to extract or filter specific fields rather than just read the whole body.

Developer Notes

The header/body split looks for the first \n\n or \r\n\r\n sequence, matching the blank-line separator defined by HTTP's message format, rather than trying to parse each line as a header field, so it works regardless of which headers are present.

API Response Formatter Use Cases

Reading a minified API response copied from a terminal or log file
Reformatting a response pasted from a browser's network panel before sharing it in a bug report
Quickly pretty-printing a bare JSON payload without headers

Common Mistakes

Pasting a response body that's actually HTML (a common shape for error pages) and expecting JSON formatting to apply.
Including a shell prompt or curl command line above the response, which breaks the header/body blank-line detection.

Tips

Paste the exact output of curl -i to get both the header block and a nicely formatted body in one pass.

API Response Formatter