| Undelivered | Twilio.Message |
| UnexpectedResponse | Control.Monad.Twilio, Twilio |
| UnsolicitedCall | Twilio.Types, Twilio.Calls.FeedbackSummary, Twilio.Call.Feedback, Twilio |
| unsuspend | Twilio.Account |
| uri | |
| 1 (Function) | Twilio.UsageRecord |
| 2 (Function) | Twilio.Account |
| 3 (Function) | Twilio.Conference |
| 4 (Function) | Twilio.Conference.Participant |
| 5 (Function) | Twilio.Message.Media |
| 6 (Function) | Twilio.Queue.Member |
| 7 (Function) | Twilio.Application |
| 8 (Function) | Twilio.AuthorizedConnectApp |
| 9 (Function) | Twilio.Call |
| 10 (Function) | Twilio.ConnectApp |
| 11 (Function) | Twilio.IncomingPhoneNumber |
| 12 (Function) | Twilio.Message |
| 13 (Function) | Twilio.OutgoingCallerID |
| 14 (Function) | Twilio.Queue |
| 15 (Function) | Twilio.Recording |
| 16 (Function) | Twilio.Transcription |
| 17 (Function) | Twilio.UsageTrigger |
| urlOrApplicationSID | Twilio.Calls |
| US | Twilio.Types.ISOCountryCode, Twilio.Types, Twilio |
| usage | Twilio.UsageRecord |
| usageCategory | Twilio.UsageTrigger |
| UsageRecord | |
| 1 (Type/Class) | Twilio.UsageRecord |
| 2 (Data Constructor) | Twilio.UsageRecord |
| usageRecordList | Twilio.UsageRecords |
| UsageRecords | |
| 1 (Type/Class) | Twilio.UsageRecords |
| 2 (Data Constructor) | Twilio.UsageRecords |
| usageRecordsPagingInformation | Twilio.UsageRecords |
| usageRecordURI | Twilio.UsageTrigger |
| UsageTrigger | |
| 1 (Type/Class) | Twilio.UsageTrigger |
| 2 (Data Constructor) | Twilio.UsageTrigger |
| usageTriggerList | Twilio.UsageTriggers |
| UsageTriggers | |
| 1 (Type/Class) | Twilio.UsageTriggers |
| 2 (Data Constructor) | Twilio.UsageTriggers |
| UsageTriggerSID | Twilio.Types.SID, Twilio.Types, Twilio |
| usageTriggersPagingInformation | Twilio.UsageTriggers |
| usageUnit | Twilio.UsageRecord |
| USD | Twilio.Types.PriceUnit, Twilio.Types, Twilio.Transcription, Twilio |
| username | Twilio.Tokens |