# Optimizing Global App Performance with HTTP/3 and QUIC

Delivery Hero achieves 17 percent faster load times by implementing HTTP/3 protocol optimizations.

- **Source:** [www.theregister.com - Articles](https://brifing.si/source/2c34ea50-d341-4a10-925d-12c012a9ad10)
- **Published:** 2026-10-30
- **Topic:** [Software & Engineering](https://brifing.si/c/engineering)
- **Original article:** <https://www.theregister.com/devops/2026/10/30/http/3-is-faster-with-some-work-and-help-from-cloudflare/5306767>
- **On Brifing:** https://brifing.si/s/1f5efe20-27a2-4ed8-bab2-cc7ef56ee5dc

## Reducing App Latency Globally

Delivery Hero, a global delivery service with 60 million users, successfully migrated most of its traffic to HTTP/3. This transition aimed to minimize network latency across diverse regions like Africa, Latin America, and Asia. By optimizing the connection layer, the company achieved a 17 percent reduction in end-to-end home screen response times.

## Transitioning from TCP to QUIC

HTTP/3 replaces the traditional TCP-based approach with the QUIC protocol, which utilizes UDP. Unlike TCP, which requires multiple round trips for handshakes, QUIC enables 0-RTT capability. This allows apps to send data while the handshake is still in progress, effectively eliminating significant delays that previously plagued users on slower, unreliable network connections.

## Eliminating Head-of-Line Blocking

A major advantage of HTTP/3 over HTTP/2 is the removal of head-of-line blocking. By sending packets in multiple independent streams rather than a single sequential string, the protocol ensures that packet loss does not stall the entire connection. This architectural shift provides a more resilient data transfer experience for mobile application users.

## Cloudflare and Client Implementation

The engineering team utilized Cloudflare’s content delivery network to facilitate the HTTP/3 rollout. While iOS support was native and straightforward, Android required integrating Google’s Cronet library. To minimize code rewrites, the team initially used the Cronet Transport for OkHttp wrapper, though this approach required further custom engineering to optimize initialization performance.

## Solving Cronet Initialization Delays

The initial Cronet implementation introduced an 800-millisecond initialization delay at P90, negating some HTTP/3 speed benefits. Engineers addressed this by forking the code into a custom bridge library called OKCronet. By overlapping this initialization process with other background tasks, they successfully reduced P95 latency from 1.2 seconds to just 120 milliseconds.

## Managing Congestion Control Algorithms

Despite the overall success, secondary screens experienced latency in markets prone to packet loss, such as Pakistan. The team identified Cloudflare’s default Cubic congestion control algorithm as the culprit. Testing revealed that Google’s BBR algorithm handled packet loss more effectively, prompting ongoing collaboration with Cloudflare to resolve these specific congestion-related performance issues.

## Fallback Mechanisms and Results

The team migrated 95 percent of users to HTTP/3, with a robust fallback mechanism to HTTP/2 for devices on networks blocking UDP traffic. This deployment cut handshake latency by 51 percent globally. In specific high-latency regions like Pakistan, the total response time was effectively halved, demonstrating the protocol's significant impact on user experience.

## Strategic Infrastructure Implications

This project highlights the necessity of fine-tuning modern protocols to match specific regional network conditions. While HTTP/3 offers clear performance gains, successful implementation requires careful management of client-side libraries and server-side congestion algorithms. For global companies, these technical optimizations are critical for maintaining competitive delivery speeds in diverse and challenging network environments.

## Sources covering this story

- https://www.theregister.com/devops/2026/10/30/http/3-is-faster-with-some-work-and-help-from-cloudflare/5306767 — 

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_Summary written by Brifing from the original reporting. Copyright in the original article belongs to its publisher; read the full piece at the link above._