System One API
System One API is the hosted decision API behind TypeSafe Jev, with an open-source TypeScript SDK for AI agents. Where the TypeSafe Jev listing covers the decision model itself, this listing covers the developer API and console: send text or app context and get back a typed choice, a score or a yes/no probability for routing tools, ranking results and checking conditions, with API keys, call logs and credit use managed in one place.
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About System One API
System One API is listed in our agent infra category and is aimed at builders. System One API is the hosted decision API behind TypeSafe Jev, with an open-source TypeScript SDK for AI agents. Where the TypeSafe Jev listing covers the decision model itself, this listing covers the developer API and console: send text or app context and get back a typed choice, a score or a yes/no probability for routing tools, ranking results and checking conditions, with API keys, call logs and credit use managed in one place. Pricing, as the maker states it: 100 free credits on sign-up; Starter $10 for 10,000 prepaid credits; no subscription. Maturity: Active. We last checked the official link on 2026-10-23.
System One API at a glance
- Category: Agent infra
- Built for: Developers and teams building with AI agents
- Pricing: 100 free credits on sign-up; Starter $10 for 10,000 prepaid credits; no subscription (as the maker states it)
- GitHub: ziyu/system-one-sdk
- Official site: system-one.dev/en
- Listed on AgentScout: Oct 23, 2026
System One API FAQ
What is System One API?
System One API is the hosted decision API behind TypeSafe Jev, with an open-source TypeScript SDK for AI agents. Where the TypeSafe Jev listing covers the decision model itself, this listing covers the developer API and console: send text or app context and get back a typed choice, a score or a yes/no probability for routing tools, ranking results and checking conditions, with API keys, call logs and credit use managed in one place.
How much does System One API cost?
System One API's pricing, as the maker states it: 100 free credits on sign-up; Starter $10 for 10,000 prepaid credits; no subscription. Check the official site for current plans.
Where can I find System One API's source code?
On GitHub at ziyu/system-one-sdk.
What are alternatives to System One API?
Similar tools include TypeSafe Jev, Grok Bot Jev Router, CocoIndex, Manifest, Nango and Windmill.
Facts from our link-checked listing, the GitHub repository and the official site. See something wrong? Suggest an edit.
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System One API alternatives
Other agent infra tools in our directory. See all agent infra tools →
TypeSafe Jev
Jev is TypeSafe's System One decision model, built for the small decisions inside software and agents. You send a state and typed questions (choice, score and more) and get typed answers with probabilities back instead of free-form text, so code can branch on them directly to route, classify, score or rank options. Agents can use it to settle narrow calls cheaply and save the larger LLM for open-ended work. Available through TypeSafe's API, Python and JavaScript SDKs, an agent skill, and OpenRouter.
Grok Bot Jev Router
Grok Bot Jev Router is an open-source Python reference router that puts TypeSafe Jev in front of Grok Bot as a cheap decision layer. Before expensive research, browser, retry or subagent work, Jev classifies the request and returns an explicit action such as reuse a cached result, stop a failing retry, cap research, run a deterministic step, or ask a human. It starts in shadow mode that only logs decisions, has an active mode for a Grok Bot skill that honors them, and includes a kill switch. It never sends, pays or deletes anything itself.
CocoIndex
Incremental data engine for keeping agent context and indexes fresh.
Manifest
Open-source LLM gateway that routes each request from agents and apps to the right model across API keys, subscriptions and local models, with spend tracking.
Nango
Integration platform that connects products and AI agents to 1,000+ APIs with managed auth, syncs and tool calls.
Windmill
Windmill is an open-source developer platform that turns scripts in Python, TypeScript, Go, SQL and other languages into webhooks, workflows and internal UIs. Its flows include AI agent steps that call an LLM with your scripts as tools, support nested agents and MCP, and run on a fast self-hostable workflow engine. It positions itself as an open-source alternative to Retool and Temporal.
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