01 / FIRST REQUEST
Quickstart
See request/response samples and illustrative curl, Python, JavaScript, TypeScript, Rust, C# and Java examples.
Open the quickstart →Documentation
Build around decisions
The Jev-compatible API supports routing, classification and scoring from text. Choose Peer-to-Peer for elastic capacity or EU for dedicated EU processing. The API accepts context and up to three typed text questions for s1-pro, or one for s1-fast and s1-vision, per request, then returns a structured answer. Public routes and schemas follow the current API contract and are published as OpenAPI 3.1.
02 / CONTRACT
API reference
Browse the static OpenAPI 3.1 contract snapshot and the request, answer and error schemas.
Open API reference →03 / DIFFERENCES
Migrate from Jev
Move the base URL and credentials, then review the documented differences and retry behavior.
Read migration notes →04 / PATTERNS
Examples
Typed routing, moderation guardrails and bounded image classification patterns.
Browse examples →ROUTING / s1-llm-auto-router
LLM auto-router model
Classify a request for an LLM router in one call: category, difficulty, stakes and four flags.
Read the router model docs →05 / PROCESSING
Regions & data
Choose Peer-to-Peer or optional EU processing; understand current routing, payload retention, usage-history settings and idempotency.
Read data handling →06 / OPERATIONS
Errors
Use request IDs, retryable errors, and `Retry-After` without repeating a charge.
Review error codes →Contract note
Examples are illustrative. The OpenAPI document is the source of truth for routes and schemas. Check the OpenAPI document again before relying on any route.
https://api.system1models.ai keeps working.