Ryan Dahl launches celld to open-source Durable Objects

Ryan Dahl, the creator of Node.js and Deno, has released celld, an open-source implementation of Cloudflare's Durable Objects and Workers. The project enables developers to deploy stateful, serverless-style compute and storage on their own infrastructure, such as private VMs and S3-compatible buckets, rather than relying on a proprietary cloud backend.

Written in Rust and JavaScript, celld is released under an Apache 2.0 license. The system is designed for high compatibility, supporting Cloudflare's Workers and Durable Objects JavaScript APIs, which allows developers to continue using familiar tooling like wrangler.jsonc. Technically, the architecture leverages V8 isolates for compute and assigns each object—referred to as a "cell"—its own SQLite database for storage. To ensure durability and coordination, state is persisted and replicated to an S3-compatible bucket.

The shift toward stateful serverless

Cloudflare introduced Durable Objects in 2020 to address a fundamental limitation of serverless computing: the difficulty of managing state. By co-locating compute and state within a single-threaded model, the primitive eliminated the complex concurrency issues typically associated with distributed systems. This architecture proved highly effective for demanding use cases, including multiplayer gaming, real-time collaborative applications, and the orchestration of AI agents. However, until now, this specific operational model was locked within Cloudflare's ecosystem.

Breaking the vendor lock-in

The launch of celld effectively liberates this primitive, allowing teams to host their memory layer and compute on providers like AWS or GCP. This shift is particularly significant for developers building AI agent workflows who require granular operational control over their data and compute environments. Beyond control, the move offers substantial financial incentives. Ryan Dahl noted that the self-hosted approach is "orders of magnitude cheaper at scale."

For example, hosting 1,000 resident cells on celld via DigitalOcean costs roughly $49 per month, whereas the estimated cost for the same capacity on Cloudflare is $4,150 per month. This price delta highlights the potential for significant cost reduction when moving away from managed proprietary services.

The road ahead

As celld moves into the wild, the industry will be watching how the community adapts the Rust-based core to various cloud environments. While the project provides a path away from proprietary lock-in, the operational burden of managing S3-compatible coordination and V8 isolates now shifts from the provider to the developer. The project's success will likely depend on how easily teams can scale these self-hosted cells compared to the seamless, albeit expensive, experience of a managed service. As the creators put it, "A primitive this good deserves to run anywhere."