CSVFormat — CSV Formatter & Converter Guides & Examples

About CSVFormat What csvformat.net actually does to your data — the parser it ships, the four places it deviates from RFC 4180, and what it will not do for you. /about · updated 2026-10-11 CSVFormat Changelog Dated changes to csvformat.net — the RFC 4180 state machine, the ragged-row warning, numeric round-trip rules, and the deviations documented honestly. /changelog · updated 2026-10-11 Contact CSVFormat Contact the operator of csvformat.net — parser bugs, conversion output that mangled data, dialect and encoding issues, and feature requests. One human mailbox, replies within two business days. /contact · updated 2026-10-12 CSV Parsers Compared: PapaParse vs fast-csv vs node-csv, and Which Ones Are Dead Streaming vs in-memory, maintenance dates from the registry, RFC 4180 handling, and the one axis that actually decides your choice. /guides/csv-alternatives · updated 2026-10-12 CSV Best Practices: Type Inference, Encoding, and the RFC 4180 Edge Cases Why automatic type inference destroys phone numbers, how quoted fields and embedded newlines actually parse, and the three checks that catch a broken export before it reaches a database. /guides/csv-best-practices · updated 2026-10-17 CSV Cheat Sheet: RFC 4180 Rules, Delimiters, and the Flags That Matter One printable screen - quoting rules, delimiter settings per locale, BOM handling, Excel and Postgres import flags, and the checks that catch a broken export. /guides/csv-cheatsheet · updated 2026-10-12 Compressing CSV: Measured Ratios for gzip, zstd, xz, and What CRLF Really Costs Real compression numbers on a 14.7 MB generated CSV, why gzip -9 was worse than -6, why CRLF costs raw bytes and nothing compressed, and streaming memory measurements. /guides/csv-compression · updated 2026-10-12 Cleaning Messy CSV Data: Headers, Duplicates, Whitespace, and Codepage Damage A repeatable order of operations for a dirty export - normalise headers, trim without destroying data, dedupe by key, and quarantine rejects instead of guessing. /guides/csv-data-cleaning · updated 2026-10-12 CSV Dialects: RFC 4180 vs Excel vs Pandas vs DuckDB The five dialect settings that actually differ - delimiter, quote char, escape behaviour, NULL marker, and line ending - with what each tool writes and what it refuses to read. /guides/csv-dialects · updated 2026-10-12 CSV Encoding and the BOM: Why Your Accents Broke and Which Fix Applies UTF-8 with and without BOM, the mojibake lookup table, CRLF vs LF, Excel's code-page behaviour, and how to detect an encoding instead of guessing. /guides/csv-encoding-guide · updated 2026-10-17 Formula Injection in CSV: Why =SUM() in a Cell Is a Security Bug How a CSV becomes an Excel formula, the payloads that execute, what the OWASP checklist actually requires, and safe output encoding that keeps exports readable. /guides/csv-formula-injection · updated 2026-10-17 CSV Hacks: Nine Tricks That Make a Boring Format Do More Force Excel to keep leading zeros, ship arrays in one column, embed JSON safely, quote only what needs it, and debug a file you cannot open. /guides/csv-hacks · updated 2026-10-12 CSV Libraries in 2026: The Streaming Parsers Beat the One-Call Parsers npm download counts for CSV and spreadsheet parsers over 2024–2026, why the streaming stack outran the convenience stack, and the one package whose npm copy has not moved since 2022. /guides/csv-libraries-2026 · updated 2026-10-12 CSV Parser Maintenance Health, Read From the Registry Release dates, maintainer counts, and dependency counts for eight CSV packages, pulled from the npm registry. Downloads are the wrong signal for a 200-line parser; here is the one that is not. /guides/csv-parser-maintenance · updated 2026-10-13 CSV Patterns and Gotchas: Duplicate Headers, Ragged Rows, and Silent Pads Six behaviours that make a valid-looking CSV wrong - duplicate header keys, ragged rows, quote-after-value, blank-line collapsing, trailing comma, and the newline count that never matches. /guides/csv-patterns-and-gotchas · updated 2026-10-12 Your Quoted CSV Fields Are Being Trimmed RFC 4180 says a quoted field keeps everything inside the quotes. This parser trims it anyway. Measured on the shipped code, with the four quoting rules that actually apply. /guides/csv-quoting-changes-your-data · updated 2026-10-13 CSV to JSON: Header Mapping, Nested Payloads, and What Round-Trips Badly Two canonical JSON shapes for CSV data, how to convert nested JSON to CSV and back without losing types, and the round-trip cases that break silently. /guides/csv-to-json · updated 2026-10-12 CSV to SQL: INSERT Statements, COPY Recipes, and the NULL Trap When generated INSERTs are the right tool, how to batch them, Postgres COPY and MySQL LOAD DATA recipes, and the empty-string-vs-NULL mistake. /guides/csv-to-sql · updated 2026-10-12 CSV to SQL Quietly Turns Your Zip Codes Into Integers The INSERT generator decides what is a number, and its rule is Number(v). That means leading zeros, IDs over 2^53, and hex strings all change value on the way into your table. /guides/csv-to-sql-quietly-changes-values · updated 2026-10-13 CSV Parsing in 2026: Parsers Growing 4–6×, JSON Converters Flat npm download counts for the five biggest CSV libraries over 2024–2026, why the shape of the growth curve matters more than the percentages, and what install counts genuinely cannot show. /guides/csv-trends-2026 · updated 2026-10-12 Large CSV Files: Where the Browser Stops and What to Use Instead Real size ceilings for an in-browser converter, streaming parsers that keep memory flat, DuckDB one-liners, and how to sanity-check a file you cannot open. /guides/large-csv-files · updated 2026-10-12 Where This Parser Disagrees With RFC 4180, Measured Six behaviours of the shipped CSV parser that differ from RFC 4180, each produced by running the real function out of the deployed page under Node. Two of them lose data silently, one emits SQL that will not parse. /guides/rfc4180-deviations · updated 2026-10-12