Why OpenRouter? OpenRouter isn't just a gateway to paid AI juggernauts. It also serves a treasure trove of free models – from Mistral 7B to Llama 2, even GPT‑3.5 Turbo at times. For bootstrapping a SaaS, that’s a game changer. The Playbook Pick your free model. Visit openrouter.ai/models and filter by cost: $0 . Look for models with decent rate limits (e.g., Mistral 7B gives 10 req/minute). Integrate with the same API key. OpenRouter’s API is OpenAI‑compatible. Drop a free model endpoint into your existing OpenAI SDK, and you’re live. No extra boilerplate. Ship fast, upgrade later. Free models handle summarization, classification, simple chat, and content generation. Validate your idea without burning cash. When you need scale or quality, swap to a paid model with one line of code. Pro Tips Use context caching to reduce token usage. Implement rate‑limit retries with exponential backoff. Combine free models for different tasks: e.g., Llama for chat, TinyLlama for classification.…