Nice framework design! One pattern I have found invaluable when working with dozens of APIs is adding automatic retry with exponential backoff and rate-limit header parsing. Most APIs return Retry-After or X-RateLimit-Reset headers — parsing these and sleeping accordingly saves you from getting banned. I have built clients for 78+ different APIs (Reddit, Spotify, HN, ArXiv, etc.) and the abstraction that pays off most is separating pagination strategy from the HTTP layer. Some APIs use cursor-based, others use offset — having a pluggable pagination interface keeps your client clean. Would love to see how you handle API-specific auth flows (OAuth2 vs API keys vs JWT) in your framework.