gRPC

• RPC (Remote Procedure Call): Execute a function in the destination target

HTTP/2

• gRPC uses HTTP/2 (launched in 2015)
• Uses the same TCP connection (multiplex), instead of opening multiple requests
• Data flow as binaries, instead of text
• Headers are compressed

Protobuf

• Protocol Buffers (Protobuf): Mechanism for serializing structured data to a binary data

gRPS connection types

• Unary: Client (Request) - Server (Response)
• Server streaming: Client (Request) - Server (Multiple responses)
• Client streaming: Client (Multiple request) - Server (Reponse)
• Bidirectional streaming: Client (Multiple request) - Server (Multiple response)

Advantages & Disavantages

• Advantages
• Type safety
• Transmits binary data
• Auto-generation of client code for most languages
• Disadvantages
• No curl-like tool for ad hoc testing
• Will not work with some cloud load balancers
• More complicated than TCP or Redis
• Data not human readable
• It's most helpful when...
• Used by client from different programming languages
• You have a lot of MSs with several methods
• You are transmitting large amount of data

Using gRPC with javascript

• Requires the lib @grpc/proto-loader