| OpenAI, Gemini, Anthropic, provider APIs | Direct provider access and first-party model features. | You manage provider accounts, payment rails, catalog differences, and per-provider metering yourself. |
| OpenRouter | OpenAI-compatible access and provider routing across many models. | Payment is account/API-key based, not x402 settlement per paid HTTP request. |
| LiteLLM | Self-hosted proxying, provider normalization, and budget controls. | It is a proxy layer, not the Compose x402 facilitator or receipt model. |
| AI SDK | App-side TypeScript abstractions for model calls. | It is a client library. Compose is a paid HTTP gateway the AI SDK can call. |
| Cloudflare Workers AI, Together AI, Fireworks, Hugging Face Inference Providers | Provider or router-specific inference APIs. | They are upstreams or peers in routing. Compose adds session budget, x402, and receipt handling around calls. |