| Range | Serv.Internal.Header.Name, Serv.Internal.Header, Serv.Header |
| range | Serv.Internal.Header.Name, Serv.Header.Proxies |
| Raw | Serv.Internal.Api, Serv.Api |
| RawText | |
| 1 (Type/Class) | Serv.Internal.RawText, Serv.Common |
| 2 (Data Constructor) | Serv.Internal.RawText, Serv.Common |
| Rec | Serv.Internal.Rec |
| RecordIso | Serv.Internal.Rec |
| Referer | Serv.Internal.Header.Name, Serv.Internal.Header, Serv.Header |
| referer | Serv.Internal.Header.Name, Serv.Header.Proxies |
| ReflectDecoders | Serv.Internal.MediaType |
| reflectDecoders | Serv.Internal.MediaType |
| ReflectEncoders | Serv.Internal.MediaType |
| reflectEncoders | Serv.Internal.MediaType |
| ReflectHeaderNames | Serv.Internal.Header |
| reflectHeaderNames | Serv.Internal.Header |
| ReflectHeaders | Serv.Internal.Header |
| reflectHeaders | Serv.Internal.Header |
| ReflectName | Serv.Internal.Header.Name, Serv.Internal.Header, Serv.Header |
| reflectName | Serv.Internal.Header.Name, Serv.Internal.Header |
| ReflectQuery | Serv.Internal.Query |
| reflectQuery | Serv.Internal.Query |
| ReflectVerb | Serv.Internal.Verb |
| reflectVerb | Serv.Internal.Verb |
| reorder | Serv.Internal.Rec |
| reproxy | Serv.Server |
| request | Serv.Internal.Server.Context |
| requestedRangeNotSatisfiable416 | Serv.Server |
| requestEntityTooLarge413 | Serv.Server |
| requestHeaderFieldsTooLarge431 | Serv.Server |
| requestHeadersSeen | Serv.Internal.Server.Context |
| requestTimeout408 | Serv.Server |
| requestURITooLong414 | Serv.Server |
| required | Serv.Internal.Header.Serialization |
| resetContent205 | Serv.Server |
| resortHeaders | Serv.Internal.Server.Type |
| Response | |
| 1 (Type/Class) | Serv.Internal.Server.Type, Serv.Server |
| 2 (Data Constructor) | Serv.Internal.Server.Type |
| retag | Serv.Server |
| RetryAfter | Serv.Internal.Header.Name, Serv.Internal.Header, Serv.Header |
| retryAfter | Serv.Internal.Header.Name, Serv.Header.Proxies |
| RoutingError | |
| 1 (Type/Class) | Serv.Internal.Server.Error |
| 2 (Data Constructor) | Serv.Internal.Server.Type |
| routingError | Serv.Internal.Server.Type |
| runServer | Serv.Internal.Server.Type |
| runServerWai | Serv.Internal.Server.Type |