How to export a csv from Google Sheet API?

The following URL gives you the CSV of a Google spreadsheet per sheet. The sheet must be accessible by the public, by anyone with the link (unlisted).

The parameters you need to provide are:

• sheet ID (that is simply the ID in the URL of a Google Spreadsheet https://docs.google.com/spreadsheets/d/{{ID}}/edit)
• sheet name (that is simply the name of the sheet as given by the user)

https://docs.google.com/spreadsheets/d/{{ID}}/gviz/tq?tqx=out:csv&sheet={{sheet_name}}

With that URL you can run a GET-request to fetch the CSV. Or paste it in your browser address bar.

You can use the Drive API to do this today -- see https://developers.google.com/drive/v3/web/manage-downloads#downloading_google_documents, however that will limit you to the first sheet of the document. The Sheets API doesn't expose exporting as CSV today, but may offer it in the future.