JSON - Online linter

Find a quick and easy online JSON linter tool. Paste your JSON string to display it as a clear, readable tree-view with code folding features.

November 8, 2024 · 2 min read

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Christophe

Markdown, WSL and Docker lover ~ Insatiable curious.

Cet article existe aussi en français — lire la version française.

This article is over a year old but was reviewed on July 30, 2026 — the content is still accurate.

This article is part of the code quality series:

JSON - Online linter

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TL;DR

This article introduces the author's free JSON Linter tool (source on GitHub, hosted at jsonlint.avonture.be) for pasting a JSON string and viewing it as a foldable, readable tree — useful for both syntax-checking JSON you're writing and inspecting API responses. It also mentions the Chrome "JSON Formatter" extension for auto-formatting JSON pages in the browser.

Exactly like my SQL - Formatting tool, it's always useful to have a tool in your favorites that lets you copy/paste a JSON character string and display it as a tree-view with or without a code folding feature.

I use it quite regularly when I'm writing a JSON string and I want to check that there are no syntax errors (lint) or, on the other hand, and for example, when I call an API that returns JSON and I want to analyze the code received. In these cases, the collapse functionality comes in very handy.

Two alternatives depending on the context: jq when you're already in a console, and Rendering a JSON file as a mind map when the structure matters more than the values. To produce test JSON rather than read it, see JSON - Faker & Mockup.

Retrieve my JSON Linter tool and sources on https://github.com/cavo789/jsonlint.

The tool is accessible online: https://jsonlint.avonture.be/

Demo