> For the complete documentation index, see [llms.txt](https://docs.ngsurvey.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.ngsurvey.com/installation-setup/system-settings/mailing-server/iis-smtp-exchange-server-2.md). # Twilio / Sendgrid Enables ngSurvey to use Twilio / SendGrid messenging API. ## 🔅 Twilio / SendGrid properties * **`API key`** the token provided by your Twilio account for sending emails. * **`Webhook handler`**can be used and set within your Twilio account to track bounced and invalid emails. * **`Restrict globally to one sender`** if enabled it allow us to specify one email and name that will be used for all email sending processes within ngSurvey. If activated ngSurvey will only use the email specified and will not use anymore the user account email and wont allow the user to enter any email for any of the email features like campaigns, tasks. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.ngsurvey.com/installation-setup/system-settings/mailing-server/iis-smtp-exchange-server-2.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.