Diogo Almeida and Jev
Diogo Almeida is a former OpenAI researcher and a co-inventor of the RLHF work behind ChatGPT. Today Diogo Almeida is the mind behind Jev, TypeSafe AI's first System One model.
Who is Diogo Almeida?
Diogo Almeida is a former OpenAI researcher and one of the co-inventors of the reinforcement learning from human feedback (RLHF) work that made ChatGPT possible. He co-founded TypeSafe AI with Erik Gafni and Sasha Sheng. If you have used a modern chatbot, you have felt the influence of Diogo Almeida's research.
The RLHF background
RLHF is the training technique that aligns large language models with human preferences. As a co-inventor of that method, Diogo Almeida helped shape how today's chat models learn to be helpful. But the same research that made chat useful also convinced Diogo Almeida that chat is not where most intelligence belongs.
Why Diogo Almeida built Jev
Diogo Almeida's thesis is simple: people should not be the only consumers of intelligence. Most of it, he argues, should live quietly inside software rather than in a chat window. That belief is why Diogo Almeida built a model that makes typed decisions instead of chatting.
- Chat puts a human in the loop for every answer.
- Most software decisions are small, repetitive, and hidden.
- Diogo Almeida wanted intelligence embedded in code, not conversation.
- So Jev returns a typed decision your program can act on directly.
What Jev is
Jev is TypeSafe AI's first System One model, launched in September 2026 with $40M in seed funding led by DCVC. Instead of returning text, it returns typed, calibrated decisions: a choice, a score, or a noul. Responses come back in 70 to 500 milliseconds at $0.042 per million input tokens, with output free. That is the product Diogo Almeida set out to build.
Jev is trained with RLCD, or Reinforcement Learning for Calibrated Decisions, which tunes the model so its confidence scores actually mean something. It is the natural next step from the RLHF work Diogo Almeida is known for: instead of aligning text to human taste, RLCD calibrates decisions for software.
Understanding Diogo Almeida helps you understand Jev: Diogo Almeida is someone who helped invent the chatbot and then chose to move past it.
See also: What is Jev · Use cases · Get Jev
Related: RLCD · System One model · Jev vs an LLM
Try what Diogo Almeida built
See Jev in the playground, or get a key and make your first typed decision.