This is the real moat, the training data, they even said it, it's the meticulously crafted data that they bet on

Even then, TypeSafe AI point out that "Jev doesn't have deep knowledge of niche domains, but you can supply context to help it decide. If you’d like Jev trained on your use cases, let us know."

This is same case with LLM's which allows you to also fine tune it.