A16z Podcast

Stainless founder Alex Rattray joins a16z partner Jennifer Li to talk about the future of APIs, SDKs, and the rise of MCP (Model Context Protocol). Drawing on his experience at Stripe—where he helped redesign API docs and built code-generation systems—Alex explains why the SDK is the API for most developers, and why high-quality, idiomatic libraries are essential not just for humans, but now for AI agents as well.They dive into:The evolution of SDK generation and lessons from building at scale inside Stripe.Why MCP reframes APIs as interfaces for large language models.The challenges of designing tools and docs for both developers and AI agents.How context limits, dynamic tool generation, and documentation shape agent usability.The future of developer platforms in an era where “every company is an API company.”Timecodes: 0:00 – Introduction: APIs as the Dendrites of the Internet1:49 – Building API Platforms: Lessons from Stripe3:03 – SDKs: The Developer’s Interface6:16 – The MCP Model: APIs for AI Agents9:23 –