Rules

Never use required

As the project involving, any fields may become optional. But if it is defined as required, it can not be removed.

So required should not be used.

Never change the ordinal

To be back compatible, the ordinal of the field SHOULD NOT be changed.

Naming

file name

The names of messages are all lowercase, with underscores between words. Files should end in .proto.

my_message.proto            // Good
mymessage.proto             // Bad
my_message.pb                // Bad

Message Name

Message names start with a capital letter and have a capital letter for each new word, with no underscores, and with PB as postfix: MyMessagePB

message MyMessagePB       // Good
message MyMessage         // Bad
message My_Message_PB     // Bad
message myMessagePB       // Bad

field name

The names of messages are all lowercase, with underscores between words.

optional int64 my_field = 3;        // Good
optional int64 myField = 3;         // Bad