The OptionChainRequest object is used as an input in GetOptionChainForUnderlier API. This API is used to acquire the option chain.

OptionChainRequest

Field Name	Data Type	Accepted Values/Examples
RequestId	google.protobuf.Int32Value	A user-supplied request ID that can be used to disambiguate response data
SymbolRoot	string	Symbol root for options
UserToken	string	A server generated GUID that is given as response to the client during the first login