CSV vs JSON

When to use which format for your data

Same Data, Two Formats

CSV

name,role,active
alice,admin,true
bob,editor,false
carol,viewer,true

JSON

[
  { "name": "alice", "role": "admin", "active": true },
  { "name": "bob", "role": "editor", "active": false },
  { "name": "carol", "role": "viewer", "active": true }
]

Comparison Table

AspectCSVJSON
StructureFlat rows and columnsNested objects and arrays
ReadabilitySimple, spreadsheet-likeHierarchical, programmatic
File sizeCompact for tabular dataLarger (key names repeated)
StreamingEasy to stream row-by-rowHarder (need to parse arrays)
SchemaImplicit (header row)Explicit (keys in each object)
ToolingExcel, Google Sheets, BI toolsAPIs, databases, dev tools
Spreadsheet compatibilityNative import/exportRequires conversion

Verdict

Use CSV for spreadsheets, bulk imports, and flat tabular data — Excel, Google Sheets, and BI tools work natively with it. Use JSON for APIs, nested data, and programmatic exchange — it supports hierarchies and is the standard for web services.

DuskTools converts between CSV and JSON in both directions.

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