open-alternative-jev

Open alternative to Jev: typed, calibrated decisions from any open-weights LLM in one forward pass (HF + vLLM), with benchmarks

Open-source alternative to TypeSafe's Jev: a System One style model layer that gives typed, calibrated decisions from any open-weights LLM in one forward pass (HF + vLLM), with honest benchmarks

How it uses Jev

Open-source System One models: typed, calibrated decisions from any open-weights LLM, in one forward pass. An open alternative to the idea behind TypeSafe's Jev, running on your own GPU with models you already have. Python package open-alternative-jev , import name so1 ("System One"). Also known as: open Jev, Jev alternative, open-source System One model.

Getting started

The answer is always one of your options, and it comes with a probability.

Source: community catalog. Details and metrics reflect the published community snapshot and are not a performance endorsement. Documentation details extracted from GitHub · the README · the project website.

Keep exploring

Similar to open-alternative-jev

Browse all
jevk5 project preview
Jev alternatives & open source
JevK5: open-weight alternative to TypeSafe Jev. Typed decisions with probabilities in one forward pass; Apache-2.0 weights and code.
system-one-open project preview
Jev alternatives & open source
Open replica of TypeSafe's Jev: typed calibrated decisions in one forward pass, on Gemma 4 E2B / Gemma 3 270M (Modal)
system-one-gemma project preview
Jev alternatives & open source
Open-source Jev-style System One decision model. Gemma 3 270M with a scoring head — fast, calibrated decisions in a single forward pass. No text generation. Inspired by TypeSafe.ai's Jev.
wev project preview
Browser & computer use
Local, open-weights decision model for browser agents: a drop-in for System One / Jev requests
jevmlx project preview
Benchmarks & research
Jev-style parallel constrained decisions for any MLX model on Apple Silicon. Typed, schema-valid JSON in one forward pass.
decider project preview
Benchmarks & research
One-pass typed decisions with calibrated probabilities (System One style model), fine-tuned from Qwen3.5-2B
agent-jev project preview
Benchmarks & research
AgentJev-0.6B - a fast 'System One' decision model for AI Agents: feed it any unstructured state (diffs, traces, logs) and structured questions, get calibrated probability distributions back in one ~50ms forward pass. Zero output-token decoding.
llm2jev project preview
Applications
Any chat model, any engine (SGLang, vLLM, transformers) as a Jev-compatible probability decision service: one prefill, one label token
snap project preview
Demos & playgrounds
Typed decisions from unstructured state: one forward pass, zero generated text. Local, deterministic, Jev-compatible. Not affiliated with typesafe.ai.