Boosting Performance and Scalability: How Cloudflare Containers Revolutionize Browser Run

Introduction

Cloudflare has significantly enhanced Browser Run by rebuilding it on top of Cloudflare’s Containers. This migration brings higher usage limits, faster performance, and improved reliability—all available immediately without any changes required from users. Developers can now spin up 60 browsers per minute via the Workers binding and run up to 120 concurrently, a fourfold increase over previous limits. Quick Action response times have dropped by more than 50%. Additionally, the team can now ship fixes and new features faster than ever. This article explores how the migration was accomplished and the metrics behind these improvements.

What Is Browser Run?

Browser Run allows developers to programmatically control and interact with headless browser instances running on Cloudflare’s global network. This capability is useful for end-to-end testing of web applications, securely investigating suspicious URLs, rendering PDF documents, and performing quick actions like capturing screenshots or extracting content. More recently, it has become a critical enabler for AI agents to interact with the web. Cloudflare aims to make Browser Run the go-to platform for responsibly using automated browsers at massive scale, with security and performance at its core.

Outgrowing the Old Infrastructure

Before adopting Cloudflare Containers, Browser Run shared infrastructure with Browser Isolation (BISO). While the two services were technically similar, BISO’s larger container images led to slower startup times and hindered development. Crucially, BISO browsers lacked optimal global distribution, which compromised both resiliency and latency. Moreover, typical BISO users had long, steady sessions, while Browser Run’s usage was short and spiky. This mismatch created scaling bottlenecks and availability delays. After internal development, Cloudflare released Durable Object (DO)-enabled Containers in open beta last year, providing the opportunity to adopt a more suitable platform. By building on its own platform, Cloudflare could identify and fix pain points ahead of external customers.

Dual Support During Migration

The migration began gradually. A Worker was inserted into incoming request paths to route a small number of users to Container-powered browsers alongside those from BISO. This dual support allowed the team to compare performance, isolate implementation bugs, and build confidence in the Container-driven approach.

The Migration to Containers

As confidence grew, the team first used Container browsers for all Quick Actions endpoints. Next, they enabled Container browsers for connections via the Workers browser binding on free accounts, followed by pay-as-you-go accounts. This phased rollout validated stability before extending to all contract customers. The transition required no action or existing Worker redeployments from customers, ensuring a seamless upgrade.

Challenges: Performance and Scale Bottlenecks

Despite the benefits, the migration presented challenges. The spiky nature of Browser Run usage meant that containers had to be rapidly provisioned and deprovisioned while maintaining consistent response times. Cloudflare’s global distribution was crucial to keeping latency low, but optimizing container startup times and global routing required careful tuning. The team leveraged DO-enabled Containers to manage state and lifecycle efficiently, overcoming bottlenecks that had previously limited concurrency.

Benefits: Higher Limits, Faster Performance, Rapid Feature Delivery

The results speak for themselves. With the new container infrastructure, users can spin up 60 browsers per minute and run up to 120 concurrently—four times the previous limit. Quick Action response times have dropped by more than 50%, making the service noticeably snappier. Additionally, the team can now ship fixes and features faster because the container environment is more flexible and easier to update. These improvements are live today, and no user action is required to benefit.

Conclusion

Rebuilding Browser Run on Cloudflare Containers has unlocked substantial performance and scalability gains. By migrating carefully and leveraging DO-enabled Containers, Cloudflare has delivered a faster, more reliable service that meets the demands of modern web automation and AI interaction. The team continues to iterate rapidly, with more improvements on the horizon.

Learn more about Browser Run capabilities and the migration background.