Protect a range or an entire sheet in Google Sheets from edits, optionally warning-only or restricted to specific editors.

Documented steps

1. POST https://sheets.googleapis.com/v4/spreadsheets/{spreadsheetId}:batchUpdate using OAuth scope https://www.googleapis.com/auth/spreadsheets.
2. Add requests[0].addProtectedRange.protectedRange.range = GridRange for a specific area (zero-based, half-open indexes), or a GridRange containing only sheetId with no row/column bounds to protect the whole sheet.
3. Set protectedRange.description (optional label) and protectedRange.warningOnly (boolean) — true shows an edit warning but still allows the edit; false enforces the protection.
4. When warningOnly is false, set protectedRange.editors.users[] and/or editors.groups[] (email addresses) and editors.domainUsersCanEdit to control who may still edit; use protectedRange.unprotectedRanges[] (GridRange array) to carve out exceptions inside a protected sheet.
5. Do not set protectedRange.protectedRangeId or protectedRange.requestingUserCanEdit — both are server-assigned/read-only output fields.
6. Docs: https://developers.google.com/workspace/sheets/api/reference/rest/v4/spreadsheets/request | https://developers.google.com/workspace/sheets/api/samples/ranges | https://developers.google.com/workspace/sheets/api/limits