Free · Turn a parser error into a simple next step

JavaScript Syntax Error Explainer

Show the broken line, exact caret, parser message, and a short fix hint.

  • Real Acorn 8.18 parser
  • Private in your browser
  • Code is parsed, never run

Explain syntax error

Paste JavaScript, choose module or script mode, and let Acorn inspect the syntax without running the code.

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Add JavaScriptThe code is parsed, never run
Private syntax parsingAcorn 8.18.0 · latest ECMAScript · code is never executed
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See the resultReady when you are
Your code result will appear here

Acorn can check syntax and find code parts without running a single line.

Three simple steps

How to use it

  1. Paste code with a syntax problem.
  2. Read the marked line and simple hint.
  3. Fix it and check again.

Your code stays on this device

Acorn reads the JavaScript inside this browser tab and never runs it. Bookify does not upload or save the code. Input, syntax-tree depth, node count, table rows, and AST JSON all have clear limits.