JavaScript stack trace analyzer

Paste a Node.js, browser or TypeScript stack trace. Get the error type, every frame, and the first line that points to your own code — node_modules noise filtered out. Runs fully in your browser.

How to read a JavaScript stack trace

The first line is the thrown error. Each at … line is one frame — one function call on the path to the crash. The frames are listed most-recent call first: the top frame is where the error happened, not necessarily where the bug is.

• Start at the top frame that lives in your source tree — node_modules, (internal/…) and node:… frames are library noise, highlighted dim here.
• Check the error message pattern — Cannot read properties of undefined almost always means an uninitialized value one frame up the call chain.
• Async stack traces — with --async-stack-traces (default in modern Node) you see at async … frames; the ordering still holds.

Which runtimes are supported?

This page focuses on JavaScript / TypeScript (Node, Deno, Bun, browsers, React Native). The full toolbox also parses Python tracebacks, Java, .NET, Go and Rust panics with the same privacy guarantees.

Is my stack trace uploaded anywhere?

No. Parsing happens entirely in your browser's JavaScript engine. The page is a single static HTML file — it works with no network connection and sends nothing anywhere.

Need the full toolbox?

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