API Response Formatter

Pretty-print JSON and XML API responses with configurable indentation and optional key sorting.

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Input
Output

About api response formatter

API Response Formatter is a small tool that does one job while you watch. Nothing is saved, so a reload gives you a clean start.

Once the page has loaded it needs nothing further from the network. Work on a plane, on a train, or behind a firewall that blocks everything.

You will find it under APIs & HTTP, alongside 25 other tools for the same sort of job.

How to use it

01
Start it
Every control is on the tool itself. Keyboard shortcuts, where there are any, are listed beside it.
02
Watch it run
It updates in the page as you go. Nothing is sent anywhere, so it keeps working with the network off.
03
Close when done
Nothing is stored between visits. Reloading gives you a clean start rather than picking up where you left off.

Examples

Format JSON API Response
Pretty-print a minified JSON API response with 2-space indentation
Input
{"id":1,"name":"Alice","email":"[email protected]","roles":["admin","user"]}
Output
{
  "id": 1,
  "name": "Alice",
  "email": "[email protected]",
  "roles": [
    "admin",
    "user"
  ]
}

Questions

Does API Response Formatter work offline?+

Yes. It is JavaScript running in this tab, so once the page has loaded it needs nothing further from the network. Put the machine in flight mode and it carries on. Nothing you do here is sent anywhere, because there is nowhere for it to go.

Does it remember anything between visits?+

No. Reload the page and it starts from nothing. There is no account, no saved state and no cookie holding your last session. That is a deliberate trade: it cannot lose your data because it never keeps any.

Is it accurate?+

Timing comes from performance.now(), the high resolution clock the browser provides, rather than from setInterval, which drifts by a few milliseconds every tick and compounds over minutes. What can still shift things is the browser throttling a tab in the background, so leave it visible if the timing matters.

Does it make a sound?+

Where a sound makes sense, it is generated with the Web Audio API rather than loaded as a file, so there is nothing to download and nothing to block. Browsers refuse to start audio until you have interacted with the page, which is why the first press is what switches it on.

Can I use API Response Formatter on a phone?+

Yes. The controls are sized for touch and the layout collapses to one column on a narrow screen. Bear in mind that a phone locking its screen will suspend the page, and timing stops with it.