# Jev API

> Independent developer guide to Jev, TypeSafe AI's decision model: typed Noul, Choice, and Score answers with probabilities. Not the official Jev website.

## Verified access — 2026-09-30
JEV is TypeSafe AI's decision model. Send state and questions (Noul, Choice, Score); get typed values and probabilities rather than generated prose. jevapi.io is a developer guide operated by the BeatAPI team, independent of TypeSafe.
Best for: fixed-option routing, triage, rubric scoring and semantic checks. Not best for: open-ended writing or permission enforcement.
BeatAPI free model: jev-1.13-free. $0 input/output, zero balance allowed. Default auto key group. POST https://api.beatapi.io/v1/systemone (alias /v1/decisions), Bearer key. Context: 32K state + questions.
Free allowance per account: 1 successful request/minute before first top-up, up to 10/minute after any top-up, separate from paid allowance. 429: honor Retry-After.
Paid model: jev-1.13, $0.042 per 1M input tokens, output not billed. Paid limits follow account allowance. Provider contracts and aliases differ; JEV is not a chat-completions model.
Source: https://beatapi.io/jev-api ; https://docs.beatapi.io/decisions
Evidence: public documentation, not an authenticated benchmark.

## Core pages
- [Jev API — Fast, Typed Decisions for Software](https://jevapi.io/): Learn JEV API integration with typed decisions, practical examples, and safe fallbacks. Explore Noul, Choice, and Score, then start building on BeatAPI.
- [Chat Analysis with Jev — Probabilities and Reply Drafts](https://jevapi.io/chat-analysis/): Analyze a chat with Jev: probabilities for interest, momentum, effort balance and next-step readiness, then reply drafts that fit the odds. Works for crushes, partners and friends.
- [What Is Jev? System One Decision Model Explained](https://jevapi.io/what-is-jev/): What is Jev? Learn how the Jev decision model turns state into typed Noul, Choice, and Score answers with probabilities for software automation.
- [Jev API Guide — Requests, Responses and Integration](https://jevapi.io/jev-api/): Jev API guide covering request structure, Noul, Choice and Score questions, typed responses, integration patterns, errors, and production safeguards.
- [Free JEV API — Start Through BeatAPI](https://jevapi.io/free-jev-api/): BeatAPI currently provides the free JEV API. Create a key and start calling Jev today at no cost to begin.
- [Jev vs LLMs — Typed Decisions vs Generated Text](https://jevapi.io/jev-vs-llms/): Jev vs LLMs: compare typed probabilistic decisions with open-ended text generation, including output shape, latency, uncertainty, use cases, and system design.
- [18 Jev Use Cases: From Agent Routing to RAG Verification](https://jevapi.io/blog/jev-use-cases/): A practical guide to 18 Jev use cases for agents, routing, classification, guardrails, RAG, reranking, verification, scoring, and structured extraction.
- [Jev vs Laya: Hosted API or Self-Hosted Alternative?](https://jevapi.io/blog/jev-vs-laya/): Compare Jev’s hosted API with self-hosted Laya. See matching request examples, practical limits, and what to verify before switching.
- [Free JEV API: From First Request to Safe Decisions](https://jevapi.io/blog/jev-api-first-request/): Try the free JEV API through BeatAPI: get a key, understand rate limits, send a curl request, and validate typed responses before automating decisions.
- [Jev Use Cases — Six Patterns to Build Against](https://jevapi.io/use-cases/): Six Jev use cases with a dedicated page: agent routing, guardrails, completion verification, LLM-as-a-judge, RAG filtering, and semantic policy checks.
- [Jev Agent Routing: Choose the Next Tool or Action](https://jevapi.io/use-cases/agent-routing/): Route an agent’s next tool, subagent, or retry with Jev Choice: a full request and response, threshold bands, failure modes, and when not to use it.
- [Jev Guardrails: Gate Risky Actions with Probability Thresholds](https://jevapi.io/use-cases/guardrails/): Gate risky agent actions with Jev Noul and Score: a full request and response, review thresholds by reversibility, failure modes, and fail-closed defaults.
- [Jev Agent Completion Verifier: Confirm a Goal Before You Stop](https://jevapi.io/use-cases/agent-completion-verifier/): Check an agent’s completion claim against acceptance criteria with Jev Noul: a full request and response, threshold bands, failure modes, and when not to use it.
- [Jev as an LLM-as-a-Judge Alternative: Typed Evaluation at Scale](https://jevapi.io/use-cases/llm-judge-alternative/): Replace prose LLM-as-a-judge evaluation with Jev Choice and Score: a full request and response, threshold bands, failure modes, and when a written critique still earns its cost.
- [Jev RAG Evidence Filter: Screen Passages Before Generation](https://jevapi.io/use-cases/rag-evidence-filter/): Filter retrieved passages for relevance, support, and injection risk with Jev Noul before they enter a RAG generation context.
- [Jev Semantic Policy Check: Enforce Rules Ordinary Code Cannot Parse](https://jevapi.io/use-cases/semantic-policy-check/): Check content or a proposed action against a natural-language policy with Jev Noul: a full request and response, threshold bands, failure modes, and when a hard rule is the better fit.
- [About jevapi.io — Independent Jev API Developer Guide](https://jevapi.io/about/): An independent developer guide to the Jev decision model: how it is written, what counts as evidence, who maintains it, and how it is kept current.
- [Jev API Sources, Verification Method and Update Policy](https://jevapi.io/sources/): Where each Jev claim on jevapi.io comes from: primary documentation, evidence labels, and the date each fact was last checked.
- [Jev API 指南 - 请求、响应和集成](https://jevapi.io/zh/jev-api/): Jev API 接入指南：涵盖请求结构、Noul、Choice、Score 问题类型、类型化响应、集成方式、错误处理与生产环境安全措施。
- [免费 JEV API —— 通过 BeatAPI 开始使用](https://jevapi.io/zh/free-jev-api/): BeatAPI 目前免费提供 Jev API 访问。创建一个 Key，今天就能免费开始调用 Jev。
- [Free JEV API 接入教程：从首次请求到安全决策](https://jevapi.io/zh/blog/jev-api-first-request/): 免费接入 JEV API：通过 BeatAPI 获取密钥，了解免费模型与限额，运行 curl 示例，并在业务分流前校验 Noul 响应与处理失败。
- [Jev API ガイド — リクエスト、レスポンス、統合](https://jevapi.io/ja/jev-api/): Jev API のリクエスト構造、Noul・Choice・Score の質問、型付きレスポンス、組み込み方、エラー処理、本番運用の安全対策を解説します。
- [無料 JEV API —— BeatAPI から始める](https://jevapi.io/ja/free-jev-api/): BeatAPI は現在、Jev API への無料アクセスを提供しています。キーを作成すれば、今日から無料で Jev の呼び出しを始められます。
- [JEV API を無料で使う：初回リクエストと安全な分岐](https://jevapi.io/ja/blog/jev-api-first-request/): BeatAPI で JEV API を無料で試す手順を解説。API キーの準備、無料モデルの制限、curl の実行、Noul 応答の検証とエラー処理まで確認できます。
- [Jev API 가이드 — 요청, 응답 및 통합](https://jevapi.io/ko/jev-api/): Jev API의 요청 구조, Noul·Choice·Score 질문, 타입 기반 응답, 연동 패턴, 오류 처리와 실서비스 안전장치를 설명합니다.
- [무료 JEV API —— BeatAPI에서 시작하기](https://jevapi.io/ko/free-jev-api/): BeatAPI는 현재 Jev API에 대한 무료 액세스를 제공합니다. 키를 만들고 오늘부터 무료로 Jev를 호출해 보세요.
- [무료 JEV API 시작하기: 첫 요청부터 안전한 분기까지](https://jevapi.io/ko/blog/jev-api-first-request/): BeatAPI에서 무료 JEV API를 사용해 보세요. API 키 준비, 무료 모델의 요청 제한, curl 예제, Noul 응답 검증과 오류 처리 방법을 안내합니다.
- [Guia da API Jev: solicitações, respostas e integração](https://jevapi.io/pt/jev-api/): Aprenda a integrar a API Jev: solicitações Noul, Choice e Score, respostas tipadas, tratamento de erros e controles para uso em produção.
- [API JEV Grátis — Comece Pela BeatAPI](https://jevapi.io/pt/free-jev-api/): A BeatAPI atualmente oferece acesso gratuito à API Jev. Crie uma chave e comece a chamar a Jev hoje sem custo.
- [API JEV grátis: da primeira requisição à decisão segura](https://jevapi.io/pt/blog/jev-api-first-request/): Use a API JEV grátis pela BeatAPI: obtenha uma chave, confira os limites, execute um exemplo curl e valide a resposta antes de automatizar decisões.