Laya is nowhere close to Jev in the 3rd party benchmarks I've seen, rather Laya is among the lowest scoring of the scores of Jev-alikes
example ranking shared in comment on this HN post
example ranking shared in comment on this HN post
Stepping back from Laya, there are dozens of Jev-a-likes now, most built on LLMs, whereas it is speculated that Jev likely uses transformers, but is not LLM like by generating a token at a time. Most likely they are reaching into the logits to get the details and assembling the json object deterministically. This is what the various LLM spins are doing, which is probably close but not the same as Typesafe.
This is the main PR (merged) for using DiffusionGemma (diffusion generally) for Jev-a-likeness in vLLM. https://github.com/vllm-project/vllm/pull/57250