jev-1.13.0, Sep 25, 2026Independent handbook · Sep 2026
Jev AI: the unofficial handbook
Everything you need to use TypeSafe's Jev model: what it returns, how to get access on four channels, what it costs, and how to fix the errors you will hit. Every page is checked against live API calls.
Start here
Section titled “Start here”What is Jev?The decision model that returns choices, scores and yes/no probabilities instead of text.
Your first Jev callFive minutes from API key to a working request in curl, Python or JavaScript.
Jev API pricing$0.042 per million input tokens, free output, and what real requests cost.
Errors and fixesEvery error code we reproduced, from 401 to max_tokens_exceeded.
Jev at a glance
Section titled “Jev at a glance”| Item | As of September 25, 2026 |
|---|---|
| What it is | A “System One” model from TypeSafe AI that answers typed questions about text |
| Current version | Jev 1.13 (jev-1.13.0); jev-latest and jev-preview point to it |
| Question types | Noul (yes/no), Choice (one of up to 255 options), Score (your own scale) |
| Price | $0.042 per million input tokens; output is free |
| Speed | 253 to 378 ms per small request in our tests (median 284 ms) |
| Input limit | About 32,000 tokens for the state plus the longest question |
| Access | New TypeSafe signups paused since Sep 22; also on Vercel, OpenRouter and Cloudflare |
Popular questions
Section titled “Popular questions”- Is Jev an LLM? What is known about how it works.
- Is Jev free? The free options and their catches.
- Can I still sign up? The waitlist, the signup pause, and how to use Jev now.
- Is Jev down? Live status, recent outages and what to check first.
- Can you fine-tune Jev? What TypeSafe allows instead.
- Does Jev train on your data? Training, retention and zero data retention.
- Jev alternatives Open-source look-alikes, LLMs and classifiers.
- Can Jev hallucinate? What “can’t hallucinate” really covers.
- Is Jev open source? Weights, papers and local alternatives.
- Can Jev generate text? Why not, and how to pair it with an LLM.
- Why is it called Jev? The Jevons paradox behind the name.
- All questions
Four ways to call Jev
Section titled “Four ways to call Jev”| Channel | Model name | Before your first call |
|---|---|---|
| TypeSafe API | jev-1.13.0 |
An existing TypeSafe account (new signups paused) |
| OpenRouter | typesafe/jev-1.13 |
Prepaid credits |
| Vercel AI Gateway | typesafe-ai/jev |
A card on the Vercel team |
| Cloudflare Workers AI | typesafe/jev |
A Cloudflare account with AI Gateway credits |
The differences that break code, such as the yes/no type being called boolean on Vercel and noul everywhere else, are in Jev channels compared.
What’s new
Section titled “What’s new”- Sep 25, 2026: Vercel’s free Jev promotion ends; Jev now costs $0.042 per million input tokens on Vercel too, with free output.
- Sep 22, 2026: TypeSafe pauses new signups two days after dropping the waitlist; existing accounts keep working.
- Sep 21, 2026: Python SDK 0.7.1. Vercel starts accepting TypeSafe’s own request format, so the official SDKs work there with a new base URL; OpenRouter documents the same.
- Sep 19, 2026: Cloudflare adds Jev to Workers AI as
typesafe/jev. We add first-hand error reference pages after testing every error code on the official API. - Sep 18, 2026: OpenRouter lists
typesafe/jev-1.13. The Python SDK reaches 0.7.0. - Sep 15, 2026: TypeSafe launches Jev in early access. Vercel AI Gateway lists it the same day, free under a launch promotion.
Full history: Jev changelog.
Where to find things in TypeSafe’s docs
Section titled “Where to find things in TypeSafe’s docs”TypeSafe’s official documentation at docs.typesafe.ai is the primary source for everything on this site. If you are looking for a specific official page:
| You want | Official location |
|---|---|
| The HTTP API reference | docs.typesafe.ai, “API reference” |
| Prices, limits and model aliases | docs.typesafe.ai, “Models” |
| How to write questions | docs.typesafe.ai, “Primitives (Questions)” |
| Known weaknesses of Jev 1.13 | docs.typesafe.ai, “Jev 1.13 jaggedness” |
| Worked examples | docs.typesafe.ai, “Cookbooks” |
| Service status | status.typesafe.ai |
| API keys and the Playground | console.typesafe.ai |
This site adds what the official docs do not cover: the resale channels, real error messages and where they differ from the docs, measured latency and cost, and plain answers to the questions developers keep asking.
About this site
Section titled “About this site”Jev AI Guide is an independent handbook written by developers who use Jev. It is not affiliated with TypeSafe AI. Every page lists its sources and the date its facts were last checked. How we check what we publish.