This is an example on retrieving realtime quotes using Protobuf.
It contains an example using JSON messages and the more complex, but slightly faster Protocol Buffers.
For ProtoBuf, the library protobuf.js is used.
More on prices: https://www.developer.saxo/openapi/learn/pricing
Interactive demo: https://saxobank.github.io/openapi-samples-js/websockets/protobuf/