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Text Bracket Matcher
Check quoted plaintext brackets and download the first issue with Unicode code-point offsets and line positions.
Plain text, UTF-8 text file
JSON report
Browser only
Runs locally in your browser. Your files, pasted content and generated output are not uploaded. Reset clears this tool’s working data.
This tool needs JavaScript. If it does not load, refresh the page and try again.
How to use this tool
- Enter Text input or choose a UTF-8 text file (optional); a selected file takes precedence.
- Select Check brackets. Offsets count code points from zero; line and column start at one.
- Select Download result to save bracket-report.json. Cancel stops an active worker; edit input or run again to recover.
Examples
For ([)], the first issue is the closing parenthesis where a closing square bracket was expected.
Limitations
- At most 1,048,576 UTF-16 units and 10,000 open pairs, with a 1 MiB report and 30-second worker deadline. A chosen UTF-8 file must also fit 5 MiB.
- An apostrophe starts a quote. Comments, backticks and angle brackets have no special meaning; this does not validate a programming language.
- Report order is first closer mismatch, otherwise an open quote or dangling quote escape, otherwise the earliest unclosed opener. Uploaded BOM and CRLF/CR/LF are retained; textarea input normalizes line endings to LF. CRLF consumes two offsets and one line break.
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