Methods, systems, and computer readable media for providing message encode/decode as a service are disclosed. According to one method for providing message encoding or decoding as a service, the method occurs at an encode/decode function (EDF) node. The method includes receiving a message encode or decode operation request containing a message identifier and an operation identifier. The method also includes performing, using the operation identifier, a message encode or decode operation involving accessing or modifying at least one TLV element decoded from a message indicated by the message identifier. The method further includes sending a response indicating whether the message encode or decode operation was successfully performed.