CSV to JSON for API Integration: What Actually Matters

You have a spreadsheet export and a JavaScript API that expects JSON. The gap between those two things is small but annoying if you don't know what you're doing.

Here's what actually matters when converting CSV to JSON for real API use.

Why can't you just use the CSV directly?

Technically you can parse CSV in JavaScript, but most APIs don't accept it. JSON is the lingua franca of APIs. It maps directly onto JavaScript objects, handles nested data, and is what every modern fetch call, axios request, or GraphQL mutation expects.

CSV is flat. JSON can be flat too, but it's also structured. That difference matters the moment your API expects typed values or nested objects.

What does a basic CSV to JSON conversion actually produce?

Take a CSV like this: