Supported File Formats

FileBender supports CSV, Excel (XLSX), and JSON files as both inputs and outputs. Each format has its own configuration options. This page documents every option, its default value, and format-specific behavior.

CSV

Input CSV

Parsed with PapaParse. Supports streaming, so large files don’t need to fit in memory all at once.

Option	Type	Default	Description
delimiter	string (1 char)	,	Column separator character. Common alternatives: ;, \t (tab), |.
hasHeader	boolean	true	When enabled, the first row is treated as column names. When disabled, columns are named Column 1, Column 2, etc.
skipEmptyLines	boolean	true	Skip rows where every field is empty.

Quoting rules. Fields that contain the delimiter, a newline, or a double-quote are expected to be wrapped in double quotes ("). A literal double-quote inside a quoted field is escaped by doubling it (""). This follows RFC 4180.

Encoding. Files are read as UTF-8. Non-UTF-8 files may produce garbled text in the preview and output.

Output CSV

Option	Type	Default	Description
delimiter	string (1 char)	,	Column separator character in the generated file.
includeHeader	boolean	true	Write column names as the first row.
lineEnding	"LF" | "CRLF"	"LF"	Line ending style. Use CRLF for Windows compatibility.

Tier availability. CSV output is available on all tiers (Free and above).

Excel (XLSX)

Input Excel

Parsed with SheetJS. Requires the full file in memory (not streamed), so very large workbooks may be slower to process.

Option	Type	Default	Description
sheetName	string	(none)	Name of the sheet to read. Takes precedence over sheetIndex.
sheetIndex	integer	(none)	Zero-based index of the sheet to read. Ignored if sheetName is set.
hasHeader	boolean	true	Treat the first row (after skipped rows) as column names.
skipRows	integer	0	Number of rows to skip from the top of the sheet before reading data. Useful when a workbook has title rows above the actual table.

When neither sheetName nor sheetIndex is provided, the first sheet in the workbook is used.

Supported cell types. Text, numbers, booleans, and dates. Formulas are evaluated by SheetJS and the result value is read. Merged cells are expanded to their constituent cells.

Output Excel

Option	Type	Default	Description
filename	string	output.xlsx	Name of the generated file.
sheetName	string	Sheet1	Name of the sheet inside the workbook.

Tier availability. XLSX output requires Starter tier or above. Free-tier flows can read XLSX files but cannot write them.

JSON

Input JSON

Option	Type	Default	Description
rootPath	string	"" (root)	Dot-separated path to the array of objects within the JSON structure. For example, data.results reads from {"data": {"results": [...]}}. Leave empty when the top-level value is already an array.
flattenNested	boolean	true	Flatten nested objects into dot-separated column names (e.g., address.city). Maximum nesting depth: 5 levels.

Supported shapes. The input expects either a JSON array of objects ([{...}, {...}]) or newline-delimited JSON (NDJSON, one object per line). When rootPath is set, the value at that path must be an array of objects.

Header derivation. Column names are derived from the union of all object keys across every row. Rows missing a key get a null value for that column.

Output JSON

Option	Type	Default	Description
format	"json_array" | "ndjson"	"json_array"	Output shape. json_array writes a single JSON array. ndjson writes one JSON object per line (newline-delimited).
prettyPrint	boolean	false	Indent the output with 2-space indentation. Only applies to json_array format.
unflattenNested	boolean	false	Reverse dot-separated column names back into nested objects (e.g., address.city becomes {"address": {"city": ...}}). Maximum depth: 5 levels.

Tier availability. JSON output is available on all tiers (Free and above).

Format availability by tier

Format	Input	Output
CSV	All tiers	All tiers
XLSX	All tiers	Starter+
JSON	All tiers	All tiers

See Row Limits and Tiers for the full tier comparison.