Protocol Buffer vs Json - when to choose one over the other?

Can anyone explain when to use protocol buffer instead of JSON (and vice versa) for a microservices architecture? Both for synchronous and asynchronous communication.

When to use JSON

• You need or want data to be human readable
• Data from the service is directly consumed by a web browser
• Your server side application is written in JavaScript
• You aren’t prepared to tie the data model to a schema
• You don’t have the bandwidth to add another tool to your arsenal
• The operational burden of running a different kind of network service is too great

Advantages of ProtoBuf

• Relatively smaller size
• Guarantees type-safety
• Prevents schema-violations
• Gives you simple accessors
• Fast serialization/deserialization
• Backward compatibility

While we are at it, have you looked at flatbuffers?

Some of the aspects are covered here google protocol buffers vs json vs XML

Reference:

https://codeclimate.com/blog/choose-protocol-buffers/

https://codeburst.io/json-vs-protocol-buffers-vs-flatbuffers-a4247f8bda6f