Models & Pricing: jev-1.13.0, Costs, Limits & Honest Benchmarks
Updated 2026-09-20
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Everything currently known about the Jev model lineup, pricing, and operating limits — with the accuracy caveats up front where they belong, not buried in a footnote.
Model IDs
| ID | What it is |
|---|---|
jev-1.13.0 | The current pinned release (Jev 1.13). Use this in production so behavior doesn't shift under you. |
jev-latest | Alias tracking the newest stable release. Convenient for evaluation; risky for production reproducibility. |
jev-preview | Alias for the preview track — newer, less battle-tested. Evaluate, don't ship. |
Rule of thumb: develop against jev-latest if you like living dangerously, pin jev-1.13.0 (or whatever the current pinned release is) for anything users depend on, and re-run your calibration set when you bump the pin.
Pricing
| Rate | |
|---|---|
| Input | $0.042 per million tokens ($42 per billion) |
| Output | Free |
Output being free is the pricing tell of the whole paradigm: Jev's outputs are tiny typed verdicts, so TypeSafe AI can afford to not meter them. The practical consequence is that your cost scales with state size and nothing else — another reason State Design (filter first, send records not documents) is a cost discipline as much as an accuracy one. A lean 300-token state costs about $0.0000126 per question batch; even a million such calls a day is ~$12.60/day before you add questions.
Limits & performance
| Figure | Notes | |
|---|---|---|
| Context window | 64k tokens total | — |
| Input cap | state + longest single question ≤ 32k tokens | — |
| Rate limit | 250k tokens/sec + 1200 requests/min | Officially warned as subject to dynamic adjustment during early access — design for 429s (the SDKs back off automatically) |
| Latency | 70–500 ms per call | From the launch blog; no SLA. Fast enough for inline filtering and real-time demos (the official Doom demo ran inside a game loop), but budget the tail, not the median |
The honest accuracy caveats — read these before trusting any number
This is the part most launch coverage skips, and the part we consider mandatory:
- Independent re-tests have landed below official accuracy claims. How far below varies by task — sometimes a little, sometimes a lot.
- Accuracy is jagged. Jev can be excellent on one framing of a task and mediocre on a rephrased version of the same task. A single benchmark number — ours, theirs, anyone's — does not transfer to your workload.
- One early third-party benchmark was withdrawn. Treat the entire first wave of "Jev scored X%" coverage as suspect unless you can find the methodology and it survived scrutiny.
- No SLA on latency, and rate limits may change during early access. Don't put Jev on a hard real-time critical path without a fallback.
None of this makes Jev useless — cheap, fast, approximately calibrated judgment at volume is valuable even at "good but not magical" accuracy. It makes measuring on your own data (see Confidence & Calibration) a required step, not a best practice.
Cost math for the front-filter pattern
A concrete comparison, using list prices as of 2026-09-20: filtering 1M emails with a 400-token state costs ~$16.80 in Jev input. Running the same items through a frontier LLM at even $1/M input tokens costs ~$400 — before output tokens, which Jev doesn't charge and LLMs do. That ~25–100× gap (demos claim more; treat multipliers from demos skeptically) is the entire economic argument for Cascade Routing: Jev everywhere, LLMs only where generation pays for itself.
Where to go next
- API Reference — endpoint, fields, errors
- Getting Started — make the first call
- Cascade Routing — spend Jev calls to save LLM calls
Sources
- jevai.wiki — Model card and API reference (community documentation; model IDs, pricing, limits).
- learnjev.com — Cost & benchmarks (community documentation; independent re-test results and the withdrawn-benchmark story).
- jev101.com — 什么是 Jev(中文) (community documentation, Chinese).
Unofficial fan-made handbook. Not affiliated with TypeSafe AI or jev.com. Pricing and limits change during early access — verify at the official site before committing budget.
Related Guides
Jev API Reference: Endpoint, Request Body & Response Shapes
The System One endpoint reference: POST api.typesafe.ai/v1/systemone, the state/model/questions body, per-primitive request and response shapes, 429 handling, and SDK installation.
Confidence & Calibration: When to Trust the Number
Jev returns probability (Noul) and probability + confidence (Choice/Score). What each field means, what calibration is, and how to design confidence gates that fall back to humans or LLMs.
State Design: State Is Not a Prompt
Jev's state field is a case file for an expert, not a chat prompt. Filter in code first, name fields so questions can point at them, and keep irrelevant detail out — it measurably degrades accuracy.
What Is a System One Model? Jev vs LLMs, Precisely
System One is the model category TypeSafe AI claims Jev opens: fast, calibrated, judgment-only. The four concrete differences from LLMs, the RLCD training method, and the "not just a classifier" debate.