Is AWS Lambda still serverless?

Is AWS Lambda still serverless? With Managed Instances, MicroVMs, and Durable Functions, Lambda can now run workloads it was never designed for. AWS Serverless Hero Yan Cui explains what changed, what you give up, and why the core serverless promise still holds.
Romain sits down with Yan Cui, AWS Serverless Hero and independent consultant, to discuss how Lambda grew into general-purpose compute and where it fits for AI agents.
Key topics covered: • Why pay-per-use is no longer the whole story, and why that's fine • Lambda vs Fargate vs ECS: packaging a container image is not running a container • Lambda Managed Instances, the 90-minute timeout, and Durable Functions for jobs that run up to a year • Cold starts: why they were never as big a problem as the conversation around them • Lambda MicroVMs as a second sandbox for AI agents and CI/CD runners • AgentCore Runtime vs Lambda MicroVMs for agentic workloads • Observability for event-driven architectures, and what Lambda still gets wrong • Yan's rule: every box on your architecture diagram needs a reason to exist
Chapters: 00:00 Highlights 00:55 Meet Yan Cui, AWS Serverless Hero 05:23 Is Lambda still serverless? 14:36 Lambda vs Fargate vs ECS: where to draw the line 20:46 Lambda Managed Instances explained 24:10 Are cold starts finally dead? 29:45 Lambda MicroVMs, AI agents and S3 Files 37:51 AgentCore Runtime vs Lambda MicroVMs 45:28 What serverless still gets wrong, and observability 56:07 Yan's advice, book pick and AI security worriesWith Yan Cui (theburningmonk.com/posts), AWS Serverless Hero and independent consultant• AWS Lambda Managed Instances (aws.amazon.com/lambda/lambda-managed-instances)AWS Lambda adds 90-minute function timeout for Managed Instances (aws.amazon.com/about-aws/whats-new/2026/09/aws…)AWS Lambda MicroVMs (aws.amazon.com/lambda/lambda-microvms)Lambda Durable Functions documentation (docs.aws.amazon.com/lambda/latest/dg/durable-f…)Lambda SnapStart documentation (docs.aws.amazon.com/lambda/latest/dg/snapstart…)Amazon S3 Files with Lambda documentation (docs.aws.amazon.com/lambda/latest/dg/configura…)Agent Toolkit for AWS (aws.amazon.com/products/developer-tools/agent-…)Amazon Bedrock AgentCore Runtime documentation (docs.aws.amazon.com/bedrock-agentcore/latest/d…)Strands Agents (strandsagents.com)Eric Johnson's cloud development environment on MicroVMs and S3 Files (edjgeek.com/blog/claude-code-sandbox-for-ipad)Honeycomb (honeycomb.io)The Software Architect Elevator by Gregor Hohpe (architectelevator.com/book)Episode 198: Evolving Lambda with Michael Gasch (developers.podcast.go-aws.com/web/episodes/198…)Production-Ready Serverless workshop by Yan Cui (theburningmonk.com/hire-me)Yan Cui's blog (theburningmonk.com/posts)Work with Yan Cui (theburningmonk.com/hire-me)Yan Cui on LinkedIn (linkedin.com/in/theburningmonk)