Cloudflare Acquires Deno to Pursue Open-Source Self-Hosting for Workers

Dahl wrote on the official Deno blog that his team's work on Deno Deploy showed how much complexity remained beneath the developer experience, and that he wanted to simplify that layer. That effort led to celld, which builds on the Cloudflare Workers programming model and is intended to let developers build distributed applications from the start while keeping the system simple to operate. Dahl said he was excited that scaling is built into the programming model rather than infrastructure each application has to assemble, and that the goal is to make the model the default way to build servers on Cloudflare's network or on users' own infrastructure.

Celld, released in August, is a single Rust binary that runs Workers and Durable Objects across many machines, with object storage as its only external dependency. Operators run multiple celld instances against one storage bucket, and the software handles placement, routing and persistence. Dahl and Belder will lead an effort to merge celld into workerd and make self-hosting a supported way to run Workers applications, so customers can build on Cloudflare's network and move an application to a private data center without rewriting it.

Deno will remain open source, and Dahl's post welcomed others who want to continue its development. Deno Deploy will keep operating for six months before shutting down, and Cloudflare will provide migration support for paying customers moving to Cloudflare Workers. The JSR package registry for JavaScript and TypeScript will continue operating, with its infrastructure moving to Cloudflare.

Forbes argued that the acquisition turns a long-standing objection to Cloudflare Workers—that applications built on it cannot easily leave—into a selling point, giving CIOs evaluating serverless and edge platforms a concrete answer on portability. Dahl told The Register that he is now of the opinion that "if you're choosing Node.js for building servers, you're doing it wrong." He also said that every other server is operating at the Linux VM layer, which is not what Cloudflare Workers are.

Dahl first debuted Deno in 2018 as a rewrite of Node, with the name "Deno" an anagram of Node, to fix what he felt he got wrong with Node, including built-in fetch, a permission model and native TypeScript support. Sequoia backed Dahl's company for $21 million in 2022, and as of August Deno had amassed 400,000 monthly users. But Node's gravity proved too heavy for Deno to achieve escape velocity, Dahl told The Register: "What we found over years of working on Deno is that you can't really deviate from Node.js very much." He said continued efforts to gain adoption forced the team to backpedal on some original promises and become more Node compatible, leaving Deno as "a kind of an alternative Node.js implementation."