Cloudflare's Browser Run just received a powerful upgrade. By rebuilding the service on top of Cloudflare's own Container infrastructure, the team has unlocked significant performance and scalability improvements — all without requiring any changes from developers. Starting today, you can spin up browsers faster, run more of them concurrently, and enjoy quicker response times for quick actions.
What Is Browser Run?
Browser Run lets developers programmatically control headless browser instances running on Cloudflare's global network. Think of it as a remote, scriptable browser you can use for:
- End-to-end testing of web applications across multiple environments.
- Securely investigating suspicious URLs in a sandboxed browser.
- Rendering HTML to PDF documents with ease.
- Taking screenshots and extracting content for monitoring or automation.
- Enabling AI agents to interact with web pages — a fast-growing use case.
Built to be the go-to platform for responsible, large-scale automated browsing, Browser Run now delivers even better performance for developers who rely on it.
Why the Move to Containers?
Previously, Browser Run shared infrastructure with Browser Isolation (BISO). While the two services are technically similar, this arrangement created several bottlenecks:
- BISO's larger container images led to slower startup times for Browser Run.
- BISO browsers weren't optimally distributed globally, hurting latency and resiliency.
- BISO's long, steady sessions clashed with Browser Run's short, spiky usage patterns, causing scaling conflicts and availability delays.
Fortunately, Cloudflare recently released Durable Object (DO)-enabled Containers in open beta, giving the Browser Run team the perfect opportunity to migrate — and to eat their own dogfood, identifying pain points before external customers encounter them.
The Migration Process
The team executed a careful, gradual rollout using a Worker in the request path that could route traffic to either the old BISO-based browsers or the new Container-based ones. This dual support allowed them to:
- Compare performance side-by-side.
- Isolate and fix implementation bugs.
- Build confidence in the container approach.
The migration happened in phases: first, all Quick Actions endpoints (screenshots, PDFs, etc.) were moved to Containers. Next came connections via the Workers browser binding on free accounts, followed by pay-as-you-go accounts. Finally, contract customers were migrated — all without any required action or redeployment from their side.
Performance and Scalability Gains
The results are impressive. Here's what changed:
- 4x higher concurrency: Up to 120 simultaneous browsers can now run.
- Faster spin-up: You can now create 60 browsers per minute via the Workers binding.
- Quick Action response times dropped more than 50%, meaning screenshots, PDF generation, and URL checks happen much faster.
These improvements are live right now — no code changes needed on your end.
Faster Fixes and New Features
Beyond raw performance, the container architecture enables the Browser Run team to ship updates more quickly. Because they're no longer tied to BISO's release cycle and container build times, bug fixes and new capabilities roll out faster. This means developers benefit from a more agile, responsive service.
Looking Ahead
This migration is just the beginning. By building on Cloudflare's own container platform, the team can continue optimizing distribution, reducing latency, and increasing limits. The same approach — using internal products before releasing them externally — ensures that Browser Run evolves with real-world needs. Expect even more capabilities to emerge from this foundation.
Already using Browser Run? No action required — the improvements are automatic. New to Browser Run? Check out the overview section or Cloudflare's documentation to get started.