About JSONView
JSONView does one job: when you open a JSON document in a tab, it shows the data formatted, colour-highlighted and collapsible instead of as one long line. It is made by Benjamin Hollis, who has run the project in public for years, and the source on GitHub is MIT licensed. The author says the goal is to stay simple and rejects features that add complexity.
That restraint is the reason to pick it. JSON viewers have a mixed trust record: in 2026 the widely installed JSON Formatter added a donation prompt and its author announced a closed-source model, before saying in September that it would stay open source. JSONView has no such history in anything we found. The Chrome build is Manifest V3, last updated in May 2025, and Firefox, Edge and Chrome versions all exist. If the JSON has errors, it still shows the raw text.
It needs permission to read the pages you open and to see web requests, so it can detect JSON responses. The download is free and the author states there is no Safari version, because publishing one costs money. For plain viewing it is the safest default, with no extra features to second-guess.
Pros and cons
- Formats, highlights and collapses JSON documents
- Open source under the MIT licence, with clear ownership
- Chrome, Edge and Firefox listings
- Keeps showing raw text when JSON has errors
- Deliberately basic, with few extra features
- Chrome rating is 3.8 out of 5
- No Safari version
Permissions
It requests access to all websites and the web request permission so it can recognise JSON documents by content type, plus storage for its settings.
