| IceServer | Twilio.Tokens |
| iceServers | Twilio.Tokens |
| IE | Twilio.Types.ISOCountryCode, Twilio.Types, Twilio |
| IfMachine | Twilio.Calls |
| ifMachine | Twilio.Calls |
| IL | Twilio.Types.ISOCountryCode, Twilio.Types, Twilio |
| ImperfectAudio | Twilio.Types.Issue, Twilio.Types, Twilio, Twilio.Call.Feedback, Twilio.Calls.FeedbackSummary |
| Inbound | |
| 1 (Data Constructor) | Twilio.Call |
| 2 (Data Constructor) | Twilio.Message |
| includeSubaccounts | Twilio.Calls.FeedbackSummary |
| IncomingPhoneNumber | |
| 1 (Type/Class) | Twilio.IncomingPhoneNumber |
| 2 (Data Constructor) | Twilio.IncomingPhoneNumber |
| incomingPhoneNumberList | Twilio.IncomingPhoneNumbers |
| IncomingPhoneNumbers | |
| 1 (Type/Class) | Twilio.IncomingPhoneNumbers |
| 2 (Data Constructor) | Twilio.IncomingPhoneNumbers |
| IncorrectCallerId | Twilio.Types.Issue, Twilio.Types, Twilio, Twilio.Call.Feedback, Twilio.Calls.FeedbackSummary |
| Init | Twilio.Conference |
| InProgress | |
| 1 (Data Constructor) | Twilio.Call |
| 2 (Data Constructor) | Twilio.Conference |
| 3 (Data Constructor) | Twilio.Transcription |
| InvalidAuthToken | Control.Monad.Twilio, Twilio |
| InvalidCredentials | Control.Monad.Twilio, Twilio |
| InvalidSID | Control.Monad.Twilio, Twilio |
| IPAccessControlListSID | Twilio.Types.SID, Twilio.Types, Twilio |
| IPAddressSID | Twilio.Types.SID, Twilio.Types, Twilio |
| isoCountry | |
| 1 (Function) | Twilio.Address |
| 2 (Function) | Twilio.AvailablePhoneNumber |
| ISOCountryCode | Twilio.Types.ISOCountryCode, Twilio.Types, Twilio |
| Issue | Twilio.Types.Issue, Twilio.Types, Twilio, Twilio.Call.Feedback, Twilio.Calls.FeedbackSummary |
| issues | |
| 1 (Function) | Twilio.Call.Feedback |
| 2 (Function) | Twilio.Calls.FeedbackSummary |
| IT | Twilio.Types.ISOCountryCode, Twilio.Types, Twilio |