From REST to Reasoning Agents: Designing APIs for the AI Era
APIs have powered modern applications for decades, but AI agents and LLMs are rewriting the rules. Traditional RESTful patterns aren’t enough when your consumers are autonomous systems that demand machine-readable contracts, contextual hints, and self-discovery. This talk explores how to design APIs that work seamlessly for humans and reasoning agents alike. You’ll learn practical techniques for contract-first design, metadata enrichment, hypermedia navigation, and avoiding pitfalls like “agent drift.” Future-ready APIs start here.
APIs are no longer just for apps and developers—they’re now serving reasoning agents, LLMs, and automation platforms. To prepare for this shift, API design must evolve. In this session, we’ll explore:
- Why REST needs an upgrade → traditional design patterns weren’t built for autonomous consumers.
- Contract-first design → how OpenAPI/Swagger extensions make APIs machine-readable and agent-friendly.
- Function-calling formats → structuring endpoints so LLMs can parse, chain, and execute them reliably.
- Metadata enrichment → annotating APIs with contextual hints to improve interpretability for agents.
- Hypermedia navigation → when patterns like HAL and HATEOAS help AI agents self-discover functionality.
- Agent drift pitfalls → why autonomous consumers misinterpret APIs and how to mitigate it.
- Practical patterns for tomorrow’s APIs → real-world strategies to serve both human developers and reasoning agents.
Audience: Backend developers, API designers, architects
Takeaways:
- Design APIs that are both human- and machine-friendly
- Apply contract-first principles for LLM discoverability
- Avoid common pitfalls like agent drift and misinterpretation
About Rohit Bhardwaj
Rohit Bhardwaj is a Director of AI & Data Architecture at Salesforce, where he focuses on enterprise AI, agentic systems, cloud-native architecture, distributed systems, data platforms, security, and large-scale transformation.
Over his career, Rohit has designed and led complex enterprise platforms across AWS, Google Cloud, microservices, real-time data, API ecosystems, resilient distributed systems, and AI-enabled architectures. His work increasingly focuses on the challenges enterprises face as software evolves from deterministic services to AI-native and agentic systems—particularly around reliability, governance, evidence, security, observability, cost, and safe autonomy.
Rohit is the author of System Design with AI Interview Guide: Designing Scalable, Agentic, and Defensible Systems, published by Apress. The book presents a modern approach to system design covering scalability, distributed systems, AI architecture primitives, security, reliability, economics, agentic systems, and real-world architectures including e-commerce, ride sharing, payments, fraud detection, messaging, video streaming, file storage, and search. (Springer Link)
Book:
Amazon: https://a.co/d/09Zs1twa
Publisher / Springer Nature: https://link.springer.com/book/10.1007/979-8-8688-2782-2
O'Reilly: https://learning.oreilly.com/library/view/system-design-with/9798868827822/
Rohit is also an O’Reilly instructor and a frequent speaker at technology conferences including No Fluff Just Stuff, UberConf, GIDS, and other international events. His talks focus on practical architecture lessons from building and operating complex systems, including AI control planes, trusted agents, inference at scale, evidence-first RAG, AI security, distributed-system failure, and AI-era software architecture.
As a trusted advisor and architecture leader, Rohit works at the intersection of business strategy and deep technical architecture—helping teams translate complex business problems into scalable, resilient, secure, and economically sustainable systems.
Rohit holds an MBA in Corporate Entrepreneurship from Babson College and graduate-level education in Computer Science from Boston University and Harvard University.
Connect with Rohit:
LinkedIn: http://linkedin.com/in/rohit-bhardwaj-cloud
X / Twitter: @rbhardwaj1