How Nested JSON Becomes CSV
Nested objects are flattened with dot notation. A value such as {"user":{"email":"a@example.com"}} becomes a CSV column named user.email. This keeps nested API responses readable while still producing a flat table that spreadsheet tools can open.
Header Detection
The converter scans every row and builds a union of all keys it finds. If row one hasname and row two has email, the output includes both columns. Missing values are left as empty cells. This is useful for NoSQL-style exports where records do not always share the same shape.
Arrays and Complex Values
Arrays are serialized as JSON strings inside their CSV cell, for example ["admin","editor"]. Empty objects are written as {}, and null or undefined values become empty cells. If your target system needs arrays split into multiple rows, transform the JSON before converting it to CSV.
Delimiter Choice
- Comma: standard CSV and the best default for most tools.
- Semicolon: useful for spreadsheet locales where comma is a decimal separator.
- Tab: useful for TSV-style output or pasting into spreadsheet cells.
CSV Escaping
Values containing the selected delimiter, double quotes, or line breaks are wrapped in double quotes. Existing quotes are doubled, which is the standard CSV escaping pattern. This prevents values like ACME, Inc. or multi-line descriptions from splitting into the wrong columns.
Excel UTF-8 BOM
The UTF-8 BOM option adds a byte-order marker to downloaded files. This helps some Excel installations recognize non-ASCII text such as accented characters and emoji. Leave it off when another program complains about an unexpected marker in the first column name.
Limits to Review
Conversion happens in the browser, so very large JSON payloads depend on browser memory and device speed. For production-scale exports, streaming conversion through a script, database export tool, or ETL pipeline is more reliable.
