200k 행에 CSV와 JSON을 벤치마킹했으므로

Most “CSV vs JSON” comparisons are vibes. Here are real numbers, measured on a real dataset.

Setup: 200,000 rows x 12 columns, Node v22.18.0, no streaming tricks.

Metric Result CSV file size 20.5 MB JSON file size 49.3 MB Size ratio CSV is 2.4x smaller CSV to JSON speed ~75,234 rows/sec JSON to CSV speed ~70,908 rows/sec Round-trip Lossless

Why JSON is bigger: repeated key names on every object, plus escaping of quotes and non-ASCII characters. For log files and export pipelines the size gap translates directly into bandwidth and storage costs.

What to use: JSON for APIs and nested structures; CSV for storage, spreadsheets and analytics imports. If your data is a flat table, CSV wins on size and tooling.

I built a free in-browser converter that does JSON↔CSV↔TSV plus a bunch of text utilities, 100% client-side (your data never leaves the machine): https://instant-data-converter.vercel.app

Full guide with methodology: https://instant-data-converter.vercel.app/guides/csv-vs-json