Organization
TypeSafe AI
Model developer · Developer platform · San Francisco, California
TypeSafe AI is a San Francisco company that develops what it calls System One models, AI models that answer typed questions about supplied input with structured values and probabilities rather than generated text. Its first such model, Jev, launched in early access in September 2026 through a hosted API.453
Using this organization’s offerings
Intended users
Developers building software that needs a model's judgment as structured input to code, such as choosing an option, scoring against a rubric, or answering yes/no questions inside automated workflows.5
Hosted and self-hosted access
Jev is available through the hosted System One API, a console playground, and the Python and JavaScript SDKs. No model weights are published. The WorkflowEvals code and its Hugging Face datasets are public.6971314
Restrictions and review limits
Jev returns typed answers and probabilities, not generated text. The documentation lists known weaknesses with arithmetic, counting, dates, and multi-step indirection, says English is the primary training language, and warns that rate limits may change without notice.87
Key facts
What is and isn’t public
TypeSafe offers Jev only through its hosted API. Its documentation describes one set of weights serving all accounts, and its Hugging Face organization lists datasets but no models. TypeSafe publishes its Python and JavaScript client SDKs on GitHub under the MIT License, and its WorkflowEvals harness code under Apache 2.0 (see the WorkflowEvals record).71312101114
Products
Hosted model products
Labeled Hosted product/API — this describes how a documented product is delivered (hosted access). It does not determine whether underlying weights or code are open; assess the specific release and its licenses.
| Product | Kind | Documented delivery and access | Reviewed |
|---|---|---|---|
| System One API (Jev) (external site: docs.typesafe.ai) | Hosted model API | Hosted API (POST /v1/systemone) authenticated with API keys from the TypeSafe console, which also offers a browser playground. The current model, Jev 1.13, accepts text input only and is priced per input token. TypeSafe opened early access with a developer waitlist at launch.764 | Oct 1, 2026 |
Other products
| Product | Kind | Documented delivery and access | Reviewed |
|---|---|---|---|
| TypeSafe client SDKs (external site: docs.typesafe.ai) | Developer tool | Python and JavaScript/TypeScript client libraries for the System One API, published on GitHub under the MIT License; the Python SDK installs as the typesafe-sdk package.961011 | Oct 1, 2026 |
Cataloged artifacts
Evaluation tools
- WorkflowEvals (TypeSafe AI)Evaluation toolAvailability: Public
Notable documented facts
- TypeSafe's documentation says Jev is trained with a method the company calls Reinforcement Learning for Calibrated Decisions (RLCD), is not fine-tuned on customer data, and serves every account from the same weights.74
- TypeSafe publishes a list of known failure modes for jev-1.13, including literal reading of instructions, arithmetic and counting, date comparison, and text generation. For those tasks it advises doing the work in code or using a generative model instead.8
- TypeSafe publishes its WorkflowEvals harness and datasets, which compare models on four automation workflows. Reference labels in these datasets come from large models of other providers, not from human verification.141513
Open positions
Automated job coverage is not configured for this organization.
What this catalog does not know
- Founding date: not documented in the sources reviewed.
Have a primary source? How to report a correction.
U.S. eligibility
Eligible · basis: U.S. headquarters
TypeSafe AI's terms of use (last updated September 19, 2026) state that the site is offered by TypeSafe AI, Inc., located at 255 California St, Suite 1300, San Francisco, California, and give the same address for legal notices. The team page says staff work in person at the company's San Francisco office, and the privacy policy says the services are hosted in the United States. The terms choose Delaware law but do not state where the company is incorporated; this assessment does not rely on an SEC filing or a state registry record.132
Sources
This listing is not an endorsement or a federal approval.