How can I enable pretty-printing in Chrome manually?

JSON Formatter provides buttons to toggle between raw and formatted views of a JSON document.

It is open source. As of November 2016, the last commit was in March 2015. There are over 100 forks, many of which have more recent commits. It's not immediately clear if one of those forks is better maintained.

The OP of this answer originally wrote: "I feel like a big dummy. Some more thorough searching turned up https://chrome.google.com/webstore/detail/the-missing-json-inspecto/hhffklcokfpbcajebmnpijpkaeadlgfn/related, which is exactly what I need." However, an edited version of this answer indicated that that extension was not open source and was no longer maintained.

I ran into the same problem and dislike the bloated-ware so I develop Jipy It simply ask you to highlight (full or partial) JSON payload and trigger the format function. (hotkey, context-menu, or button)

Here is a way with Chrome 97 and no plugins.

1. Visit a API or JSON resource in the URL
2. Open developer tools. (F12)
3. Click the Source tab.
4. Open a source or hit CTRL-P
5. Select the JSON
6. In the top, select Pretty Print
7. You get nice JSON human-readable formatting!

Here is an example: