Who is the founder of Jev?
Jev is the first model from TypeSafe AI, co-founded by Diogo Almeida — a former OpenAI researcher and one of the co-inventors of RLHF, the training method behind ChatGPT. The same research that made chat useful is why he built a model that decides instead of chats.
The short answer
Jev is a product of TypeSafe AI, which Diogo Almeida co-founded with Erik Gafni and Sasha Sheng. Jev itself is not a person — it is TypeSafe's first System One model, named after the 19th-century economist William Stanley Jevons. When people search for the 'Jev founder' they almost always mean the founder of the company and the mind behind the model: Diogo Almeida.
Who is Diogo Almeida?
Diogo Almeida is a former OpenAI researcher and one of the co-inventors of reinforcement learning from human feedback (RLHF) — the alignment technique that made ChatGPT and the modern chat assistant possible. If you have used a current chatbot, you have felt the influence of his research.
- Former OpenAI researcher; co-inventor of the RLHF / InstructGPT line of work
- Co-founded TypeSafe AI with Erik Gafni and Sasha Sheng
- Built Jev, TypeSafe's first System One model, launched September 2026
- Raised $40M in seed funding led by DCVC to build it
Why the RLHF co-inventor built a decision model
His thesis is blunt: 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. RLHF put a human in the loop for every answer — great for a chatbot, wasteful for the millions of small, repetitive decisions code makes on its own. So instead of another text generator, he built a model that returns a typed, calibrated decision your program can act on directly.
| A chat LLM | Jev, the System One model |
|---|---|
| Generates text token by token | Returns one typed value in a single parallel pass |
| A human reads and decides | Your code branches on the answer |
| Confidence is implied | Confidence is calibrated (RLCD) |
| Built for conversation | Built to live inside software |
What he actually built
Jev is a non-autoregressive model: rather than writing out an answer word by word, it produces a structured value in one forward pass. That is why it returns a choice (pick one of your options), a score (a position on your scale), or a noul (a calibrated 0–1 probability) in roughly 70–500ms, with no generated prose to parse and no structured-output errors. The calibration comes from a training approach TypeSafe calls RLCD — Reinforcement Learning for Calibrated Decisions — which optimises the probabilities against real outcomes rather than human preference. Each decision costs a fraction of a cent.
The name
'Jev' is short for Jevons, after William Stanley Jevons, the economist known for work on decisions and marginal utility. 'System One' nods to Daniel Kahneman's fast, intuitive System 1 — the counterpart to the slow, deliberate reasoning a large language model does. The founder's bet is that most software wants the fast, bounded, calibrated kind.
FAQ
Who founded Jev?
Jev was built by TypeSafe AI, co-founded by Diogo Almeida (a former OpenAI researcher and RLHF co-inventor) together with Erik Gafni and Sasha Sheng. Jev is the company's first model, not a person.
Is Jev a person?
No. Jev is TypeSafe AI's first System One model, named after the economist William Stanley Jevons. People searching 'Jev founder' usually mean the founder of TypeSafe AI, Diogo Almeida.
What is Diogo Almeida known for?
He is a former OpenAI researcher and one of the co-inventors of RLHF (reinforcement learning from human feedback), the training method behind ChatGPT. He then co-founded TypeSafe AI and built Jev.
Why did the RLHF co-inventor build a decision model instead of a chatbot?
His view is that most intelligence should live inside software, not in a chat window. Chat keeps a human in the loop for every answer; Jev returns a typed, calibrated decision your code acts on directly, so the millions of small decisions software makes don't each need a person.
When did Jev launch and how was it funded?
Jev launched in September 2026, backed by a $40M seed round led by DCVC.
See also: More on Diogo Almeida · What is Jev · System One models · How RLCD works · Playground
See what he built
Run a real, calibrated decision free in the browser, then grab a jv_live_ key and drop it into your code.