JSON Formatter for Chrome, No Extension Needed

Chrome DevTools provides JSON formatting in two places. The Network tab's Preview sub-tab renders a JSON response as an interactive collapsible tree, which is useful for exploring structure but does not allow copying the formatted text as a string. The Response sub-tab shows the raw response exactly as received, which for production APIs is minified single-line JSON. If you want the formatted text to paste into documentation, a code comment, or another tool, neither DevTools tab gives you a direct way to get it. JSONView and JSON Formatter Chrome extensions address this for JSON served at a URL, but they cannot help with JSON from a log file, a clipboard payload, or an API client.

Chrome extensions like JSON Formatter and JSONView auto-format JSON when the browser navigates directly to a URL that returns a JSON Content-Type header, injecting formatted output into the page. This is useful for quickly inspecting public REST API endpoints by typing the URL directly into the address bar. However, extensions require installation steps and browser permission grants that appear alarming to security-conscious users, and they only work for URL-navigated responses rather than JSON you already have as text.

FixTools works differently from extensions: it is a standard web page that runs in any Chrome tab without installation or permissions. You paste JSON from any source (DevTools Network tab, a terminal, a log file, a Slack message, an email attachment), click Format, and get syntax-highlighted copyable output. The JSON never leaves Chrome because all processing uses the browser's native JSON.parse() and JSON.stringify() functions. This works on any device, requires no extension installation, and does not request access to your browsing history, which extensions typically require.

Chrome surfaces several JSON spec edge cases through its DevTools that are worth knowing. The Network tab Preview view tolerates trailing commas and shows the document as a tree even when the strict parser would reject it, which can give a false sense that the JSON is valid. The Response view always shows the raw bytes including any BOM, prelude, or wrapper that the server prepended; pasting that raw text into FixTools surfaces those leading characters as parse errors at position 0. The Console JSON.parse uses the strict RFC 8259 grammar, identical to what FixTools uses, so when DevTools Console shows a SyntaxError, the same error reproduces here. For NDJSON streams returned by chunked transfer encoding, Chrome shows the concatenated body in Response, which needs preprocessing into a JSON array before any formatter can handle it.

Chrome's extension ecosystem includes several JSON-focused tools that overlap partially with what FixTools provides. JSONView and JSON Formatter intercept JSON-typed responses navigated to by URL and render them in place with collapsible trees. JSONHandle and Quick JSON Formatter add similar in-page rendering with different colour schemes. None of these handle JSON from non-URL sources like log files, chat messages, or clipboard text, which is where FixTools complements them. The two patterns work well together: use a Chrome extension when you visit a JSON URL directly and want auto-formatting in place, and use FixTools when you have JSON text you need to paste and inspect. Neither approach requires the other, and developers often install one extension while keeping FixTools bookmarked for the broader case.