---
title: "About System One"
description: "A universal System One layer for Agents, with an open-source TypeScript SDK and a hosted Jev decision API."
canonical: "https://system-one.dev/en/about"
last-updated: "2026-09-20"
language: "en"
---

# About System One

A universal System One layer for Agents, with an open-source TypeScript SDK and a hosted Jev decision API.

## An API service and SDK project

System One gives application developers a shared interface for bounded decisions: classify a request, choose a workflow step, score against a rubric, or estimate whether a condition holds. Applications define the choices and decide what to do with the result.

## Hosted Jev today

The hosted API currently provides Jev-compatible choice, score, and noul evaluations. Availability depends on the configured provider and model. The SDK also has separate provider adapters; those adapters do not mean every provider or model is hosted by this service.

## Developed in the open

The TypeScript SDK is maintained in a public GitHub repository. Its 0.6 packages separate the decision client, Fetch transport, and provider adapters. Use the System One adapter and your platform API key to connect to this service.

## Keep application control

Model output informs a decision; it does not execute a tool or grant permission. Evaluate accuracy with your own data and use review or a reasoning model when uncertainty matters. No response-time, uptime, or individual prediction guarantee is published here.

## Start here

- [Developer documentation](https://system-one.dev/en/docs)
- [TypeScript SDK](https://system-one.dev/en/sdk)
- [API reference](https://system-one.dev/en/api)
- [Authentication](https://system-one.dev/en/auth.md)
- [Pricing](https://system-one.dev/en/pricing)
- [OpenAPI specification](https://system-one.dev/openapi.json)
- [Agent integration guide](https://system-one.dev/en/skill.md)
- [About](https://system-one.dev/en/about)
- [Contact](https://system-one.dev/en/contact)
- [SDK source](https://github.com/ziyu/system-one-sdk)
- [@system-one-ai/core (npm)](https://www.npmjs.com/package/@system-one-ai/core)