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Comment by lajr | Hacker News Reader

This looks promising! One of the important aspects of protocol buffers, avro etc is how they deal with evolving schemas and backwards/forward compatibility. I don't see anything in the docs addressing that. Is it possible for old services to handle new payloads / new services to handle old payloads or do senders and receivers need to be rewritten each time the schema changes?

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Good question! Compared to Protocol Buffers and Apache Avro, that each have their own specialised schema languages created by them, for them, JSON BinPack taps into the popular and industry-standard JSON Schema language.

That means that you can use any tooling/approach from the wide JSON Schema ecosystem to manage schema evolution. A popular one from the decentralised systems world is Cambria (https://www.inkandswitch.com/cambria/).

That said, I do recognise that schema evolution tech in the JSON Schema world is not as great as it should be. I'm a TSC member of JSON Schema and a few of us are definitely thinking hard on this problem too and trying to make it even better that the competition.

A lot of people already think about this problem with respect to API compatibility for REST services using the OpenAPI spec for example. It's possible to have a JSON Schema which is backwards compatible with previous versions. I'm not sure how backwards-compatible the resulting JSON BinPack schemas are however.

Great seeing you over here Michael :) For other people reading this thread, Michael and I are collaborating on a paper covering the schema compiler I've been working on for JSON BinPack. Funny coincidence!

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