JSON to CSV Converter

How this reads your output

A top-level array is used directly, and an object containing exactly one array is unwrapped, which is how most APIs wrap a collection. Each record is then flattened so nested objects become dotted column names, and the union of every key across every record becomes the header. That union matters: records with different shapes are common in JSON and impossible in CSV, so missing fields become blank cells and the count is reported.

What the results mean

Flattened from nested objects

How many columns came from nesting. A key written as user.city means the value was inside a user object.

Records missing some fields

Records that did not carry every key. Those cells are blank, which CSV cannot distinguish from a field that was present and empty.

Columns

The union of keys across all records, so a field appearing in only one record still gets a column.

Common problems and fixes

Long identifiers are mangled after opening in a spreadsheet

The spreadsheet converted them to numbers. Anything over fifteen digits loses precision and anything with leading zeros loses them, which quietly damages order numbers, product codes and phone numbers. Use the import dialogue and mark those columns as text rather than double-clicking the file.

Arrays come out as JSON inside a cell

That is deliberate for arrays of objects, because the alternative is a column for every index and a header that changes with the data. If you need those expanded, extract the nested array on its own and convert it separately, joining back on an identifier.

Frequently asked questions

More in DevTools

• JSON Tree ViewerExplore JSON as a collapsible tree, with the path of every value.
• JSON Compare / DiffDiff two JSON documents structurally instead of by text.