If you're unfamiliar with stateful serverless: it's like the actor model, where each actor maintains its own isolated, persistent state. (Think Lambda functions with local storage & runs indefinitely.) It enables easily building long-running, realtime, durable, or local-first backends with the flexibility of serverless infrastructure. The most widely used implementation is Cloudflare Durable Objects, powering products like Clerk, Tldraw, Liveblocks, and Playroom.

A few months ago we launched Rivet Actors (https://news.ycombinator.com/item?id=42472519) as an open-source alternative to Cloudflare Durable Objects. After that launch, we kept hearing three common concerns:

- Vendor lock-in: Developers are hesitant to adopt a new programming model if there's no clear off-ramp. While it's straightforward to migrate a Postgres database, stateful serverless platforms can feel locked-in due to lack of viable alternatives.

- Ecosystem: Choosing a well-known database like Postgres comes with a mature ecosystem. Adopting a new model means rebuilding tooling and patterns from scratch.

- Conceptual gap: Many developers have spent their entire careers designing systems with intentionally separated state and compute. A model that merges the two can feel backwards at first.

We realized the best solution was to build a stateful serverless framework that can (a) be portable across clouds and (b) be easily extended – similar to how Hono created a unified API for traditional serverless functions across different providers. Thus, ActorCore was born.

Today, ActorCore supports running stateful serverless on Rivet Actors, Cloudflare Durable Objects, Redis, and standalone Node.js/Bun. The most common use cases include applications using collaborative, AI agent, local-first, and per-tenant database features.

State in ActorCore is an in-memory JavaScript object, with SQLite support coming later this month. State is stored in memory near your users on the edge, removing database round trips and minimizing latency due to physical distance. Additionally, state writes have tunable consistency, which enables both fully durable compute workloads and high-frequency state updates.

You may have noticed that this still leaves concern #3: the conceptual gap. While this isn't something we can solve with a framework, I've been spending ~40% of my time working on docs, content, and examples to help resolve this. ActorCore is also turning out to be community-driven as hoped, which enables more people to try and share their experience with stateful serverless.

We'd love it if you'd give ActorCore a try, read the roadmap, and/or let us know where we can improve anything. If you're hesitant about trying stateful serverless, I'd love to learn more in the comments. Looking forward to feedback!