ExpressVPN’s Move to Qt: A Technical Post-Mortem on the 30% Speed Boost

For years, the trade-off for ExpressVPN users was simple: top-tier security in exchange for a desktop interface that often felt one step behind. That changed when the company abandoned its fragmented codebase for a ground-up rebuild using the Qt framework. One year after the initial rollout began, the "so what" for the average user is measurable: connection times have been slashed by 30%, effectively breaking a performance ceiling that had plagued the service’s desktop clients for years.

This wasn't a mere UI facelift; it was a fundamental architectural shift. Previously, ExpressVPN’s desktop presence was a patchwork of Electron and platform-specific wrappers—a setup that is notoriously memory-hungry and difficult to sync. By migrating to Qt, a C++ based framework, the apps now run significantly closer to the metal. This move stripped away the heavy layers of a Chromium-based shell, reducing background CPU overhead by roughly 15%.

Quantifiable Gains and Real-World "Grit"

The primary objective of the rebuild was raw performance, and the benchmarks deliver. Independent testing by PCMag and various network hobbyists throughout 2025 confirmed that the efficiency gains translated directly to bandwidth. On high-speed fiber connections where the old apps often plateaued around 280 Mbps, the new Qt-based architecture consistently pushes 350-380 Mbps.

However, the transition wasn't without its friction. Early beta testers on macOS reported "ghosting" artifacts when dragging the app window and a noticeable stutter when scrolling through the server list under heavy system loads. These weren't just aesthetic glitches; they were the growing pains of a massive code migration. ExpressVPN spent much of the last year deploying patches to iron out these UI lags, eventually resulting in a interface that feels "snappy" rather than just functional.

The update also addressed long-standing feature disparities:

• macOS: The integration of native WireGuard and split tunneling finally brought the Mac client into parity with Windows, ending years of "second-class citizen" status for Apple users.
• Linux: Power users gained a GUI-integrated speed test and support for dedicated IPs, moving the experience away from purely command-line interactions.
• Windows: The "Network Lock" kill switch was rebuilt to be more responsive, minimizing the micro-seconds of exposure during a connection drop.

As of December 2025, the rollout is nearing its final phase, with the company on track to hit 100% adoption across its user base by the first quarter of 2026.

Market Context and Developer Sentiment

The VPN industry is currently locked in an arms race of proprietary protocols, with rivals like NordVPN and Surfshark frequently touting their own custom builds. ExpressVPN’s decision to lean into the open-source Qt framework signals a different priority: reliability through transparency.

The move resonated with the technical community, which had grown tired of "siloed" development where the Windows app felt like a completely different product than the Linux version. One developer sentiment echoed across forums like Reddit highlighted the shift: "It finally feels like a single cohesive tool instead of three different teams trying to copy each other's homework." This move away from fragmented development has allowed for faster security patches and a more predictable user experience.

Global Infrastructure and Privacy Integration

The leaner architecture has proven particularly effective in the Asia-Pacific (APAC) region. Following server-side optimizations in Tokyo and Singapore earlier this year, the reduced handshake overhead of the Qt apps resulted in a 25% improvement in connection stability. This is a critical win for users in high-latency environments who previously struggled with "connection hanging" during the initial encryption phase.

The technical overhaul also streamlined how the apps handle evolving privacy standards. Rather than patching three different codebases to meet new transparency requirements, the unified code allows for global implementation of GDPR-compliant features and clearer data logging disclosures. By the end of 2025, the focus has shifted from rebuilding the foundation to maintaining the stability of the 3,000+ server network while ensuring the new, more efficient software handles the load of millions of concurrent users.