16 projects · checked 2026-09-20

Run a decision model yourself

Within days of the commercial API shipping, people started reimplementing its one endpoint. 16 of those projects are live enough to be worth listing.

Why this exists at all

The decision API is one endpoint with three primitives. That is a small enough surface that a competent developer can reimplement it in a weekend, which is exactly what happened. The interface spread faster than the models did.

Three different things get called self-hosting here, and they are not interchangeable.

A compatible server gives you the same call shape as the commercial API in front of weights you choose, so the client code does not change. Anadapter wraps a model you already run. A model plus serverships its own weights, which means you are also adopting whatever that model can and cannot do.

None of these have been measured by us. What follows is what each project says it is, with its star count and last push date so you can judge whether anyone is still on it. The models they serve are inthe directory, where 21 of the entries ship in a format you can run locally.

Compatible server

Exposes the same call shape as the commercial API, so client code does not change.

localjev605 ★githubnextRuns Jev-shaped decisions locally. From GitHub Next, which is the closest thing this list has to an institutional backer.TypeScript · MIT · pushed 2026-09-18openjev-sglang221 ★ekzhangA compatible endpoint on SGLang, prefill-only. Skipping generation is what makes a decision call cheap.Python · pushed 2026-09-18openjev200 ★razorback16A compatible decision server built on DiffusionGemma, one of the few taking a diffusion route rather than an encoder or a constrained decoder.Python · Apache-2.0 · pushed 2026-09-20jeff167 ★logan-markewichA self-hosted drop-in replacement powered by GliFormer. Drop-in means the client code does not change.Python · MIT · pushed 2026-09-20open-jev68 ★daseinlabsAn open implementation with its own fine-tuning pipeline attached, rather than only serving somebody else’s weights.Python · pushed 2026-09-19OpenDecision40 ★deepanwadhwaA semantic decision engine positioned as an open counterpart to the commercial API.Python · Apache-2.0 · pushed 2026-09-20open-alternative-jev34 ★ikermoelAn open alternative serving a System One style model behind the same call shape.Python · Apache-2.0 · pushed 2026-09-20laya22 ★receptronRuns Laya, the most-liked open model in the category, behind a compatible interface.TypeScript · MIT · pushed 2026-09-20openjev21 ★zhihzLocal bilingual probability decisions from context, questions and candidates. One of the few not English-only.Python · NOASSERTION · pushed 2026-09-16

One thing to check before you commit

Several of these projects claim to match or beat the commercial model. None of those claims has been checked by anyone outside the project that made it, and we have not checked them either. Treat a README benchmark as a starting point for your own test, not as a result. The one model we did measure shows what checking it actually involves.

Find out what your data actually supports

We turn your historical decisions into a frozen test set, then tell you which model, which threshold, and how much of it you can safely automate.