fast-csv
Full-featured CSV parsing and formatting library for Node.js with TypeScript support. Handles both reading (parse) and writing (format) CSV streams. Supports custom headers, validation, transformation, and error handling per row. Designed for high-throughput data pipeline use cases.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Local library with no network access. CSV injection risk if output feeds spreadsheet formulas — sanitize cell values starting with =, +, -, @ for spreadsheet use.
⚡ Reliability
Best When
You need TypeScript-typed CSV parsing with robust row-level validation and transformation in a Node.js data pipeline.
Avoid When
You need browser-side parsing or a simpler API for basic CSV reading — csv-parser is lighter for simple cases.
Use Cases
- • Parse and validate CSV records in Node.js agent pipelines with per-row transformation and error handling
- • Write structured data to CSV format for agent report generation or data export workflows
- • Transform CSV streams with rename, filter, and cast operations before database ingestion
- • Handle CSV with complex quoting, nested delimiters, and Unicode content in ETL agents
- • Build CSV round-trip pipelines (read → transform → write) with full streaming support
Not For
- • Browser-side CSV parsing — fast-csv is Node.js only; use PapaParse for browser
- • Simple one-liner CSV parsing where csv-parse or PapaParse have simpler APIs
- • Excel/XLSX format — use xlsx or exceljs for spreadsheet formats
Interface
Authentication
Local library — no authentication required.
Pricing
MIT license, maintained by C2FO.
Agent Metadata
Known Gotchas
- ⚠ headers: true automatically reads first row as headers but trimHeaderFields option must be set separately for whitespace-padded headers
- ⚠ Row transformation (transformSync/transform) runs in-stream — throwing in a transform function terminates the stream
- ⚠ discardUnmappedColumns: true is needed when CSV has more columns than headers or mapping — otherwise row parsing fails
- ⚠ TypeScript generics for row type require matching headers exactly — header mismatch causes type errors at runtime
- ⚠ Writing CSV with format.write() returns a Node.js stream — agents must handle drain events for high-volume writes
- ⚠ fast-csv does not handle BOM automatically — use skipLines: 1 with manual BOM detection for UTF-8-BOM files
Alternatives
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Scores are editorial opinions as of 2026-03-07.