Add a Data Refresh Timestamp
The API Connector add-on for Google Sheets provides an option to include a timestamp in your sheet each time your data refreshes. To access, click on the 'Output options' button and check the 'Add timestamp' box.
If you choose to add a timestamp, the timestamp of each data refresh will appear in the first column (column A) of the data output. This will shift all response data over by 1 column, so, if you are appending to existing data, insert a column first to accommodate the new timestamp. In overwrite mode, the refresh timestamp will always be printed into the first row of data after the headers, while in append mode, it will print into the first empty row.
Timestamps can be added to any request, whether scheduled or manually refreshed.
Timestamps will use the timezone of the sheet, which can be viewed by clicking File > Spreadsheet settings. They will match the default format of your locale (also viewable in your spreadsheet settings), though you can change this via date formatting options.
If you are running a scheduled refresh, and notice missing or delayed timestamps, please consult this article for troubleshooting tips: Scheduling