> For the complete documentation index, see [llms.txt](https://docs.coherent.global/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.coherent.global/build-spark-services/additional-mappings/csv-inputs-and-outputs-xcsvinput-and-xcsvoutput.md).

# CSV inputs and outputs (XCSVinput and XCSVoutput)

Syntax: `XCSVinput_<parameter>` and `XCSVoutput_<parameter>`

Comma-separated values (CSV) are more efficient for very large input and output ranges. This mapping behaves similarly to `Xinput` and `Xoutput` tables (see [Inputs and outputs (Xinput and Xoutput)](/build-spark-services/additional-mappings/inputs-and-outputs-xinput-and-xoutput.md)) except the input and output are provided as comma-separated values.

1. Select the input or output range to map.
2. Verify the first row (header row) is completely populated.
3. Select the cell containing the formula and enter a [name](https://support.microsoft.com/en-US/Excel/get-started/define-and-use-names-in-formulas) in the format of `XCSVinput_<parameter>` or `XCSVoutput_<parameter>`, for example, `XCSVinput_interest`  or `XCSVoutput_premiums`.
4. Upload the file to Spark and test in the [API Tester](/navigation/api-tester.md).

## Text formatting notes

* `XCSVinput` must be provided in escaped format.
* `XCSVinput` does not require a `"` qualifier of elements.
* For `XCSVinput` `,,`  or `,"",` are both considered as a `null`.
* `XCSVoutput` uses the qualifier `"` for all elements.