Flat CSV doesn't map naturally to nested JSON structures - until you use dot notation in your headers. Column headers like `user.name`, `user.email`, `address.street`, `address.city` automatically convert to nested objects: `{ user: { name, email }, address: { street, city } }`. Perfect for prepping data for APIs that expect nested payloads.
When to use this
Use when: importing CSV into an API that expects nested objects (most modern REST/GraphQL APIs), prepping test fixtures with realistic nested structures, migrating denormalised CSV exports into normalised JSON for a NoSQL store (MongoDB / Firestore).
Frequently Asked Questions
How do I create arrays in nested JSON?
Use bracket notation in headers: `tags[0]`, `tags[1]`, `tags[2]` produces `{ tags: ['value1', 'value2', 'value3'] }`. Or use comma-separated values in a single column with a special suffix like `tags[]` to split into an array.
What if a key collision happens?
Two columns mapping to the same path (e.g. both `user.email`) - the later column wins. The converter warns you in the preview when collisions occur so you can rename one of the columns.
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