Josh Howard, Senior Engineering Manager at Cloudflare, joins me to explain how Durable Objects and D1 work under the hood—and why Cloudflare’s approach to stateful serverless infrastructure is so unique. We get into V8 isolates, replication models, routing strategies, and even upcoming support for containers. Want to learn more about SQLite? Check out my SQLite course: https://highperformancesqlite.com/?ref=yt Follow Josh: Twitter: https://twitter.com/ajoshhoward LinkedIn: https://www.linkedin.com/in/joshthoward Follow Aaron: Twitter: https://twitter.com/aarondfrancis LinkedIn: https://www.linkedin.com/in/aarondfrancis Website: https://aaronfrancis.com - find articles, podcasts, courses, and more. Chapters 00:00 - Intro 00:37 - What is a Durable Object? 01:43 - Cloudflare’s serverless model and V8 isolates 03:58 - Why stateful serverless matters 05:14 - Durable Objects vs Workers 06:22 - How routing to Durable Objects works 08:01 - What makes them "durable"? 08:51 - Tradeoffs of colocating compute and state 10:58 - Stateless Durable Objects 12:49 - Waking up from sleep and restoring state 16:15 - Durable Object storage: KV and SQLite APIs 18:49 - Relationship between D1, Workers KV, and DOs 20:34 - Performance of local storage writes 21:50 - Storage replication and output gating 24:15 - Lifecycle of a request through a Durable Object 26:46 - Replication strategy and long-term durability 31:25 - Placement logic and sharding strategy 36:35 - Use cases: agents, multiplayer games, chat apps 40:33 - Scaling Durable Objects 41:14 - Globally unique ID generation 43:22 - Named Durable Objects and coordination 46:07 - D1 vs Workers KV vs Durable Objects 47:50 - Outerbase acquisition and DX improvements 49:49 - Querying durable object storage 51:20 - Developer Week highlights and new features 52:44 - Read replicas and sticky sessions 53:49 - Containers and the future of routing 56:47 - Deployment regions and infrastructure expansion 57:43 - Hiring and how to connect with Josh