Deno team joins Cloudflare to simplify self-hosted Workers and Durable Objects

What happened

Ryan Dahl's Deno team is joining Cloudflare to unify development efforts around self-hosting Workers and Durable Objects. The primary technical outcome will be merging celld, the open-source self-hosted implementation of Workers and Durable Objects that Deno released in August, with workerd, Cloudflare's open-source Workers runtime. Ryan Dahl and Bert Belder will lead this effort to make workerd a first-class self-hosting option.

Why the partnership matters

Workerd has been open source and production-ready, but adoption has been limited. Cloudflare acknowledged that the ecosystem around workerd lacked adjacent services and tooling needed for real-world self-hosted deployments. More critically, workerd's implementation of Durable Objects was limited to single-instance mode, suitable only for local testing and unable to scale across machines. Cloudflare's production Durable Objects implementation, by contrast, is tightly coupled to Cloudflare's infrastructure with dependencies on external services and site-reliability engineering—not a practical model for self-hosters.

Celld, released by Deno in August, solved this gap by providing a Durable Objects implementation designed for self-hosting and scalability across multiple machines. It required only a single Rust binary and external object storage as a dependency, drastically simpler than Cloudflare's distributed system. Cloudflare recognized that Deno had built what the Cloudflare team had wanted to build for some time, and approached them about joining forces.

What changes

The primary change is merging celld's distributed Durable Objects implementation into workerd. This will enable developers self-hosting workerd to use Durable Objects as a scalable, multi-instance abstraction across multiple machines, with sharded data and WebSocket connections. The merged runtime will support the same programming model as Cloudflare Workers—including bindings for secure configuration of external resources—but runnable on developers' own infrastructure.

Cloudflare plans to improve workerd's ecosystem and documentation to make self-hosting a supported, accessible path. More announcements about this work are expected in the coming months. Until then, developers can start experimenting with celld or workerd immediately.

Why it matters for developers

For developers who want distributed application primitives without being locked into Cloudflare's platform, this removes a significant barrier. Durable Objects were architected differently than traditional cloud platforms precisely because Cloudflare believes this model is superior: it makes building real-time collaboration, distributed systems, and globally distributed applications easier than classical three-tier architectures. Previously, this model was only available on Cloudflare's network. Now, developers who prefer to self-host or use alternative providers can access the same programming model.

The Workers design, with its use of V8 isolates and global network distribution, makes it possible to run applications in hundreds of locations with minimal overhead and cost. Self-hosting workerd with distributed Durable Objects means developers can adopt similar patterns on their own infrastructure, though without Cloudflare's geographic reach. The effort to improve workerd's ecosystem acknowledges that developer experience and available tooling matter as much as the runtime itself.

Addressing lock-in concerns

Cloudflare has emphasized that workerd's open-source release was not a marketing gesture but a genuine escape hatch. Major customers like Shopify required the Workers Runtime to be open source before committing to the platform in 2022. Some customers have migrated away using workerd; Cloudflare notes this is acceptable because those customers would never have adopted Workers without the open-source option in the first place. The company argues that providing an escape route is better business than creating vendor lock-in.

Kenton Varda, Cloudflare's representative, acknowledged that the company "hadn't done a great job" of building out the ecosystem around workerd to make self-hosting practical. The Deno partnership aims to fix that by bringing experienced runtime developers who understand how to create good developer experience for self-hosted JavaScript runtimes.

Source

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