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FastJev

Self-hosted Python SDK and System One-compatible API for runtime-defined Choice, Boolean and Score decisions on pinned open models, across Torch, vLLM, MLX, llama.cpp and WebGPU. Each result records probabilities, token usage, timing, model revision and prompt version, with committed row-level benchmarks.

Stars
21
Language
Python
License
MIT
Published by
Community
Last verified
Oct 2026

About this project

Deploy an open source Jev implementation on your own infrastructure. FastJev is an open source implementation of Jev for deployment on infrastructure you control. It continues SemIf as an independently maintained fork. Pinned open models run the Choice, Boolean, and Score interface through Torch, vLLM, MLX, llama.cpp, and optional EXL3 quantization. The WebGPU demo provides browser local inference.

Quoted from the project's README. Read the full README.

Highlights

  • Validates 2 to 16 options and returns typed results with probabilities, usage, timing and provenance.
  • RTX 5090 comparison: vLLM 82.73ms median for three decisions vs Torch 161.97ms and llama.cpp 2.344s.
  • Qwen3.5-4B scored 0.813 on 144 authored rows and 0.845 agreement on a TypeSafe public subset.
  • fastjev-score runs JSONL jobs and fastjev-serve exposes POST /v1/systemone and GET /v1/models.

Watch out

MIT licensed. It is an independent SemIf fork, not an official TypeSafe SDK, and results stay calibrated=False unless an identity-bound TemperatureCalibration is attached; model weights stay on upstream hosts under their own licenses.

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