Cloudflare has purchased Deno, the startup behind the JavaScript and TypeScript runtime created by Node.js inventor Ryan Dahl, bringing the entire engineering team into the company. The acquisition, announced Friday with undisclosed financial terms, marks the end of Deno's standalone runtime and cloud hosting service, both of which will be shut down as the team shifts its focus to Cloudflare Workers, the serverless computing platform the company launched in 2017. Deno's technology—particularly Celld, an open-source project released just two months ago that recreated Cloudflare's Workers programming model—will now become central to Cloudflare's own infrastructure strategy.
Deno emerged in 2018 as Dahl's effort to fix problems he saw in Node.js, especially around security and managing dependencies, and raised roughly $26 million across two funding rounds. The company later introduced Deno Deploy, a cloud hosting service that put it in direct rivalry with Cloudflare Workers. The relationship between the two firms has been rocky: in 2021, Cloudflare mistakenly blocked Deno's website and module registry after wrongly flagging TypeScript files as video content, forcing Deno to relocate its infrastructure. Then in August, Deno launched Celld, an open-source system that replicated Cloudflare's Workers and Durable Objects programming model for developers who wanted to run distributed applications on their own servers. On the Celld website, the startup openly credited Cloudflare distinguished engineer Kenton Varda and the Workers team for the underlying design, calling the project "a love letter to their idea." The standalone Deno runtime will receive monthly maintenance and security patches for another year, while Deno Deploy will close in six months, with migration help offered to paying customers. The JSR package registry will continue under Cloudflare's ownership.
In a joint blog post published Friday, Varda acknowledged that Cloudflare had struggled to make its open-source Workers runtime practical for developers operating outside its network. "Frankly, we haven't done a great job of building out the ecosystem of adjacent services and tooling to make it really work," he wrote, adding that the company had "sort of just hoped the community would step in" after releasing the runtime. Dahl, in an email interview, explained that merging efforts means "we bring ideas from Celld directly into Workerd, and Workerd benefits from the Deno company's runtime expertise." He confirmed the combined project is expected to remain open source, likely under the Apache 2.0 license already used by Celld, and said running a fleet of Workerd instances will require only "an industry-standard object storage bucket for coordination and storage." When asked about protections against vendor lock-in, Dahl argued that "only the open version wins here, because anything this fundamental to the future of how developers build on the web needs to be inspectable, portable, and usable outside a single vendor's platform."
Cloudflare intends to merge Celld with Workerd, its existing open-source runtime, with Dahl and Deno co-founder Bert Belder leading the work, aiming to simplify building and operating distributed applications using Cloudflare's programming model on independently managed infrastructure. Varda told The New Stack that Cloudflare has a commercial incentive to make the combined project viable beyond its own network, noting that broader adoption of the Workers programming model would ultimately benefit the company by expanding its total addressable market. "If the model is exclusive to us, that narrows our TAM, and ultimately makes us less competitive versus the legacy clouds," he said, acknowledging that Cloudflare had lacked the engineering expertise to deliver that vision on its own. Dahl pointed to AI agents as an important application for the technology, writing in a separate blog post that Durable Objects "bring together capabilities that are particularly useful for agent harnesses: inexpensive, serverless execution, persistent state, WebSockets, and a high-level JavaScript interface." The acquisition follows Anthropic's purchase of Bun in December 2024, which brought another prominent Node.js alternative under the ownership of a larger technology company, though Anthropic committed to continuing Bun's development while Deno's runtime development will end. The open-source community remains free to continue developing Deno after official support ends, Dahl noted, citing io.js—the community-led fork of Node.js that eventually merged back into the main project—as a precedent. The deal suggests that even well-funded startups with clear technical differentiation may struggle to compete independently against incumbents who can simply acquire the expertise they lack, particularly when the underlying technology was already inspired by the acquirer's own design.