Developer documentation
One API key, a live multi-provider model catalog, OpenAI-shaped chat, and optional machine-payment rails.
HomeAvailability: Stable
On this page
Start here
Send a routed request in about ten minutes
Claim a funded key, call Chat Completions, verify the response, then stream a second request.
Choose by what you need to do
Four paths through the documentation
Start with the contract that is live
Singular exposes its API at https://api.impossi.build/v1. The stable compatibility surface is OpenAI Chat Completions. Claude, Gemini, Kimi, DeepSeek, and other catalog models are called through that same OpenAI-shaped endpoint by changing the model ID.
Compatibility is endpoint-specific. A registered route does not automatically mean full OpenAI or Anthropic parity. The compatibility matrix in these docs is based on the current request normalizer, router, handlers, and public deployment, not route names alone.
| Surface | Status | Source of truth |
|---|---|---|
| OpenAI Chat Completions | Stable | POST https://api.impossi.build/v1/chat/completions |
| Public model and price catalog | Stable | Model catalog and pricing JSON |
| Streaming Chat Completions | Stable | OpenAI-style data-only SSE ending in data: [DONE] |
| Anthropic Messages | Limited | Provider-native route only; not a universal translation layer for the current NanoGPT/AIsa-backed pool |
| OpenAI Responses | Not a public product-key surface | Use Chat Completions |
| x402 and MPP | Deployment gated | The live 402 challenge is authoritative for enabled rails and networks |
Canonical URLs
- Web app: https://singular.impossibuild.ai
- Human documentation: https://singular.impossibuild.ai/docs
- API origin: https://api.impossi.build
- OpenAI SDK base URL:
https://api.impossi.build/v1 - Live retail pricing: https://api.impossi.build/pricing.json
- LLM-readable index: https://singular.impossibuild.ai/llms.txt
- Full LLM-readable reference: https://singular.impossibuild.ai/llms-full.txt
Choose the right documentation section
Choose the section that matches what you need now: learn by completing a working result, solve a specific task, find an exact contract, or understand why the system behaves as it does.
| Section | Use it when | Start with |
|---|---|---|
| Tutorials | You are learning Singular through a guided lesson. | Tutorials |
| How-to guides | You know the outcome you need and want a practical procedure. | How-to guides |
| Reference | You need the exact contract, field support, status, or limitation. | Reference |
| Explanation | You want to understand why the system behaves as it does. | Explanation |
What Singular adds
- A live catalog spanning multiple upstream providers behind one request shape.
- Explicit model selection or
model: "auto"for policy-based routing. - Provider health, fallback, prepaid billing, usage metering, API keys, and BYOK controls.
- A web workspace with threads, branching, comparisons, citations, spaces, sharing, and exports.
- Optional accountless per-call payment handshakes using x402 v2 or Singular-specific MPP charge methods when enabled by the deployment.
Source-of-truth order
- The response returned by the live API.
- The live pricing catalog for model IDs, context, and positive retail rates.
- This documentation for supported request shapes and known deviations.
- Upstream provider documentation for model-specific behavior.
Do not infer that every model supports every parameter. Route and model capability are separate questions.