By ByteBot
Anthropic made its first-ever acquisition on December 3, 2025, buying Bun—the JavaScript runtime that’s 5-8x faster than Node.js. The timing wasn’t coincidental. Claude Code, which ships as a Bun executable to millions of users, had just hit $1 billion in run-rate revenue six months after launch. That’s the fastest revenue ramp in software history, beating even Cursor’s record-breaking 24-month sprint to $1 billion.
This isn’t a feel-good acqui-hire. Anthropic just vertical-integrated the execution layer that powers its fastest-growing product. While GitHub Copilot and Cursor rent third-party infrastructure, Anthropic now owns the runtime. That’s a strategic moat competitors don’t have.
Why Anthropic Bought Speed
Bun handles 120,000 requests per second. Node.js manages 32,000. Claude Code’s user experience depends on that 3.75x performance gap. When developers expect instant AI feedback, milliseconds matter. Anthropic didn’t buy Bun for its developer team or its brand. They bought it because if Bun breaks, Claude Code breaks.
The technical integration runs deep. Claude Code ships as a Bun executable. Bun’s 5-8x faster cold startup means better responsiveness. Its all-in-one toolkit—runtime, package manager, bundler, and test runner—eliminates dependency hell. For a product serving Netflix, Spotify, KPMG, L’Oreal, and Salesforce, relying on a third-party runtime you don’t control is fragility Anthropic just eliminated.
Jarred Sumner, Bun’s founder, made a deliberate choice. The company had four years of runway. They didn’t need to sell. But as Sumner explained, joining Anthropic lets them skip the “VC-backed startup tries to figure out monetization” phase entirely. Instead of building billing systems, the Bun team gets to focus on building the fastest JavaScript runtime while backed by one of the world’s premier AI labs.
The $1B Milestone That Changes Everything
Claude Code reached $1 billion in run-rate revenue in November 2025—six months after becoming generally available in May. For context, GitHub Copilot took roughly 18 months to hit $1 billion. Wiz, the previous speed record holder, reached $100 million ARR in 18 months. Claude Code’s velocity is unprecedented.
This validates a thesis: developers want autonomous coding agents, not glorified autocomplete. GitHub Copilot integrated with every major IDE. Cursor built a standalone development environment optimized for AI. Claude Code took a terminal-native approach and won with context—200,000 tokens input versus the industry standard 8,000. When you can feed an entire codebase into an AI agent and get architecturally sound recommendations, line-by-line suggestions start feeling quaint.
Moreover, enterprise adoption proves this isn’t early-adopter hype. Netflix doesn’t deploy experiments to production. Spotify doesn’t standardize on tools that might disappear. These companies bet on Claude Code because it works at scale. The $1 billion milestone is revenue, not valuation—it’s customers paying for value delivered.
Open Source Promise, Corporate Reality
Anthropic committed to keeping Bun MIT-licensed and developed in public on GitHub. The same team continues working on Bun, now with Anthropic resources instead of VC pressure to monetize. For open-source skeptics who’ve watched corporate acquisitions redirect projects, this sounds familiar. But the incentive alignment is real: Claude Code’s success depends on Bun staying excellent for general JavaScript use, not just Claude-specific workflows.
The developer community’s reaction on Hacker News reveals cautious optimism. Relief about the MIT license. Questions about whether Bun will prioritize Claude Code features over general-purpose JavaScript tooling. Historical precedent suggests watching for signs of Claude-specific drift. If Bun stays general-purpose, Anthropic delivers on its promise. If features start optimizing exclusively for AI coding workflows, the forking discussions will intensify.
Infrastructure Acquisitions Are the New Moat
Anthropic’s move signals a broader shift. Microsoft, Amazon, Meta, and Alphabet are investing $405 billion in AI infrastructure in 2025—a 58% increase from 2024. OpenAI spent $1.1 billion acquiring Statsig for experimentation infrastructure. NTT paid $16.5 billion for NTT Data Group to integrate submarine cables with data centers. BlackRock bought Aligned Data Centers for $40 billion. HP acquired Juniper Networks for $16 billion to build AI-driven hybrid cloud portfolios.
The pattern is clear: from renting to owning. The 2000s cloud wars were about renting compute. The 2020s AI model wars were about renting intelligence via APIs. The 2025 infrastructure wars are about owning the stack. Runtime speed, compiler optimization, package management, execution control—these aren’t commodity services anymore. They’re competitive advantages.
Expect more. OpenAI will likely acquire or build custom runtimes. Google might buy compiler toolchains. Microsoft will deepen GitHub integration or acquire developer tooling companies. When speed becomes the moat, you can’t afford to rent it from someone else.
What This Means for Developers
Bun’s adoption will accelerate. Anthropic’s backing legitimizes production use for enterprises that were watching from the sidelines. The performance gap—5-8x faster startup times and 3.75x higher request throughput—becomes harder to ignore when it’s backed by a company generating $1 billion in revenue from a tool that depends on it.
But there’s lock-in risk. If Claude Code becomes the dominant AI coding assistant and it’s optimized for Bun, switching tools might mean switching runtimes. Node.js still commands 42.65% developer adoption for good reason—ecosystem stability and enterprise support matter. Bun sits at 2.36% adoption today, but 32% of new projects now consider it. Anthropic’s acquisition will push that number higher.
The AI coding tool market just proved itself enterprise-ready with measurable revenue, not just hype-driven valuations. The infrastructure consolidation has begun. And the fastest JavaScript runtime just became a strategic asset for the company that reached $1 billion faster than anyone else.
