CSV and JSON are the two most common formats for moving structured data between systems. They're both text-based, human-readable, and supported everywhere. But they handle data very differently, and picking the wrong one creates headaches downstream.
CSV is a flat, tabular format. Every row has the same columns, every value is a string. JSON is a hierarchical format that supports nesting, arrays, typed values (strings, numbers, booleans, null), and mixed structures.
Here's the same data in both formats:
Notice that in JSON, age is a number. In CSV, it's the string "32". This matters when you're doing math, comparisons, or type validation downstream.
| Factor | CSV | JSON |
|---|---|---|
| Human readability | Excellent — opens in any spreadsheet | Good — readable but verbose |
| File size | Smaller for flat tabular data | Larger (key names repeat per row) |
| Nested data | Not supported | Native support |
| Data types | Strings only | String, number, boolean, null, array |
| Spreadsheet import | Universal (Excel, Sheets, Numbers) | Requires conversion first |
| API responses | Rare | Standard |
| Database import | Supported by most databases | Supported by modern databases |
| Schema enforcement | None | Works with JSON Schema |
Any time a human needs to open the file. CSV opens instantly in Excel, Google Sheets, or Numbers with zero friction. For reports, exports, and data handoffs to non-technical teammates, CSV is unbeatable.
Flat tabular data with no nesting. If your data is a simple table — orders, contacts, measurements, survey results — CSV is more compact and faster to parse than JSON.
Database and analytics imports. Most SQL databases, data warehouses, and analytics tools (Tableau, Power BI, Looker) have native CSV import. It's the universal data handoff format.
API data. REST APIs almost universally return JSON. If you're working with API data — fetching, storing, or transforming it — staying in JSON avoids unnecessary conversion and type loss.
Nested or hierarchical data. An order with line items, a user with multiple addresses, a product with variants — this data doesn't flatten cleanly to CSV. JSON handles it natively.
Configuration files. JSON (and its derivatives like JSONC and JSON5) is the standard format for application config. CSV would be absurd here.
When data types matter. If downstream code depends on age being a number and not a string, JSON preserves that. CSV doesn't.
Our data converter handles CSV ↔ JSON conversion in your browser. For CSV to JSON, the first row becomes the object keys and subsequent rows become array entries. For JSON to CSV, nested objects are flattened one level deep. Drop your file in the Data Files panel and select your output format.