Ryan Dahl created Node.js, the tool that made JavaScript the language of servers, then spent years building Deno because he thought Node had gotten the fundamentals wrong. On October 9 he folded that project into someone else’s platform.
Dahl’s path to this point was a decade in the making. He created Node.js in 2009 and watched it become the backbone of modern server software, then delivered a 2018 talk titled “10 Things I Regret About Node.js” and began building Deno as a cleaner answer: secure by default, with native TypeScript support and a promise to fix the mistakes he saw in his first creation.
Cloudflare announced on October 9 that it is acquiring Deno, the startup Dahl co-founded with Bert Belder, and bringing the entire team into the group that builds Cloudflare Workers. The financial terms were not disclosed.
The deal is not really about the Deno runtime. It is about a small project the team shipped in August called celld, a single Rust program that lets developers run the Workers programming model, the same code and APIs that normally execute on Cloudflare’s edge network, on their own servers instead.
That capability fills a gap Cloudflare has never quite closed. For years, companies that wanted Workers’ simplicity but had to keep data inside their own data centers had no good option: the programming model was tied to Cloudflare’s network. celld, and the team behind it, offered a way to run the same code anywhere.
Kenton Varda, the principal engineer for Cloudflare Workers, said the company was delighted by celld and plans to merge it with workerd, Cloudflare’s own open-source Workers runtime. The goal, he wrote, is to make it far easier to self-host Workers and Durable Objects, so developers can use the same primitives outside Cloudflare’s network.
Dahl put the ambition in blunter terms. His team, he wrote, is joining Cloudflare to make the Workers programming model a mainstream way to build servers. The phrasing matters: after years of running a rival, Dahl is now arguing that the winning architecture is the one he spent a decade competing against.
celld was the missing piece. Written as a single Rust binary, it runs Workers and Durable Objects, the primitives Cloudflare built for distributed applications, on infrastructure the customer controls. For a bank that cannot legally put customer data in a foreign data center, or a manufacturer that wants the Workers model on its own metal, celld offered the programming model without the cloud.
The deal removes a competitor and adds a capability at once. Deno Deploy, the company’s hosted service for running Deno code, competed directly with Workers; it will shut down in six months, with paying customers steered toward Cloudflare. The Deno runtime itself will receive security and bug fixes for another year, after which its development will end, though the code remains open source.
Deno had raised about $26 million, including a Series A led by Sequoia, and its path from independent runtime to acquisition shows how hard it is to build a business on developer tools. The project won affection from engineers but never a large enough base of paying customers.
Some of Deno’s other assets will carry on. JSR, the JavaScript package registry Deno spun up and handed independent governance in early 2025, will keep operating, with its infrastructure moving to Cloudflare’s systems. rusty_v8, Deno’s bindings to the V8 JavaScript engine, will continue and be folded into workerd.
The acquisition is Cloudflare’s second in developer tools in four months, following its purchase in June of VoidZero, the company behind the Vite build tool. The pattern is plain: Cloudflare is buying the open-source infrastructure developers already use, then wiring it to its network.
The strategic logic runs deeper than tools. Cloud providers are spending enormous sums on AI computing, and enterprise customers are pushing back, demanding that data and code stay on their own premises. Giving Workers a self-hosting path is an answer to that pressure, a way to keep the programming model even where the cloud is not welcome.
For Cloudflare, the price of the deal, which neither company disclosed, is secondary to the team. It is buying the engineers who spent years solving exactly the problem the company now wants solved: how to run a server platform anywhere, on a customer’s own hardware as easily as on one company’s network.
Dahl built Node.js, watched it take over the server, and then tried to replace it. Now he will help build the thing that could succeed his own creation, on terms set by someone else. For a developer who has spent his career defining how servers are written, it is a quiet kind of surrender, and for Cloudflare, a useful one.
