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Free CSV Linter: Validate CSV Syntax Line by Line

CSV Lint — Free Syntax Validator

Paste or upload a CSV and get a line-by-line report of structural problems: ragged rows, unescaped quotes, BOM, mixed line endings, smart quotes. Runs entirely in your browser, nothing is uploaded.

Or upload a .csv / .txt file

Nothing leaves your browser. No upload, no sign-up.

About CSV Lint

Paste or upload a CSV and get a free line-by-line syntax report: ragged rows, unescaped quotes, BOM, mixed line endings.

Paste raw CSV text or upload a file and get an immediate, line-numbered report of structural problems, before any parser silently rewrites or drops them: field-count mismatches (unescaped delimiters), unclosed quotes, a stray BOM, mixed CRLF/LF line endings, curly smart quotes, and duplicate or blank header names. Unlike a tool that first parses your file and shows you the result, CSV Lint inspects the raw bytes so it catches the exact issue a strict downstream parser (pandas, Shopify, a database COPY command) would reject on.

Category: Transformation & Logic

Common Use Cases

  • Checking a CSV for syntax errors before it hits a strict import (Shopify, a database, a CI pipeline)
  • Diagnosing exactly which line is causing a pandas ParserError or similar parsing failure
  • Verifying a hand-edited or scripted CSV export is well-formed before sending it to someone else

Key Features

  • Line-numbered report of every structural issue, not just a pass/fail score
  • Detects field-count mismatches, unclosed quotes, BOM, mixed line endings, and smart quotes
  • Auto-detects the delimiter (comma, semicolon, tab, pipe)
  • Works on pasted text or an uploaded file, entirely client-side

Run CSV Lint first to see exactly which lines and rules are broken, then use Auto Fix to repair structural issues automatically, or fix the source file by hand at the exact line numbers reported.

Frequently Asked Questions

How is this different from Auto Fix?

Auto Fix repairs issues automatically. CSV Lint only reports them, line by line, so you can see exactly what is wrong (and where) before deciding how to fix it, or before handing the file to a strict system that will reject it on the same issue.

Does it upload my file anywhere?

No, parsing and validation both run entirely in your browser. Pasted text and uploaded files never leave your device.

What counts as an error versus a warning?

A field-count mismatch, an unclosed quote, or mixed line endings are flagged as errors because they will break most strict parsers. A stray BOM, smart quotes, or a blank/duplicate header name are flagged as warnings because they often still parse, but can silently misbehave in specific tools like Shopify’s import.

Built for anyone who needs to know precisely what is wrong with a CSV, and where, before it fails somewhere less forgiving.

Read the related guide →