Nested JSON to Excel — Flatten API Data for Spreadsheets
Last updated: 23 May 2026
API responses rarely arrive as a flat table. You get nested objects, arrays inside objects, and metadata next to record lists. Flattening nested JSON to Excel manually is slow and error-prone — this guide covers how automated flattening works and what to expect in your spreadsheet.
Flattening nested objects
With Separate columns mode, nested paths become column headers joined by dots, for example customer.address.city. That matches how analysts search and filter in Excel. Choose JSON in one cell when you want to preserve a subtree as formatted JSON text instead.
API wrappers (data, results, items)
Many APIs return { "data": [ {...}, {...} ], "meta": {...} }. The converter locates the main record array and ignores pagination metadata for the row set. Supported wrapper keys include data, results, items, records, rows, entries, payload, hits, and others. Nested envelopes like data.items are handled when the records live one level down.
Arrays in a row
Arrays of simple values (strings, numbers) often appear as a comma-separated cell. Arrays of objects may become dotted columns such as line_items.sku. Multiple top-level arrays of objects (for example orders and users in one file) can map to separate Excel tabs.
JSON inside string fields
Webhooks sometimes store a second JSON document inside a string field. When flattening is enabled, those strings can expand into additional columns — useful for Stripe, Shopify, and custom event pipelines without a second parse step.
Limits to know
Extremely deep nesting (dozens of levels) may hit safety limits. Very wide rows (thousands of unique keys) can produce large sheets. For production analytics, consider filtering fields at the source API when possible.
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