Based in Boston USA, Tracksmith are a premium running apparel brand dedicated to celebrating and supporting amateur and expert runners alike.

We have worked in partnership with Tracksmith since 2016, supporting them on various digital initiatives including a successful migration to headless Shopify Plus architecture. More recently, we helped them migrate web framework from Nuxt to Astro , which ultimately led to improvements in conversion rate and abandonment rates.

The Challenge: A Time-Sensitive and Essential Migration

The Tracksmith store was originally built on Nuxt 2.0 and Vue, but with Nuxt 2.0 reaching end-of-life, a critical decision had to be made. The team needed to determine whether to upgrade to Nuxt 3.0 or seize the opportunity to transition to a new framework. A swift resolution was necessary to maintain site security and prevent further slowdowns in development velocity. After evaluating Astro as a potential alternative, we identified several key advantages, including enhanced performance, faster time-to-feature, and improved security resilience.

The Solution: Adopting a Future-Ready Framework 

To ensure long-term scalability and efficiency, we identified four key objectives for the migration:

• Performance – Enhancing site speed by minimising JavaScript on the frontend and leveraging built-in browser APIs.

• Maintainability – Improving testing capabilities through Astro’s decoupled architecture, allowing for greater portability and long-term flexibility.

• Stability – Creating a more robust and reliable site with fewer bugs and reduced downtime, thanks to Astro’s Island Architecture.

• Velocity – Accelerating development speed and simplifying ongoing maintenance by reducing reliance on third-party services and lowering overall site complexity.

As part of the migration, we also assessed shifting from a Single Page App (SPA) to a lightweight Multi Page App (MPA). After evaluating factors such as performance, UX, initial load time, engineering complexity, and long-term maintenance, we determined that migrating Tracksmith.com to an MPA would provide the best balance of speed, efficiency, and sustainability.

Why Astro?

Astro is a highly scalable web framework designed for fast, content-driven websites. Its Island Architecture ensures each page element operates independently, enhancing resilience, maintainability, and overall site robustness. Unlike other frameworks that load all JavaScript components—regardless of whether they are needed—Astro takes a more efficient approach. It only loads essential interactive elements, such as navigation menus, search bars, and responsive design logic, ensuring a smoother and faster user experience.

This selective loading prevents unnecessary slowdowns caused by non-essential features like dropdown menus that aren't always in use or off-screen animations that only activate on specific interactions. Additionally, Astro is framework-agnostic, seamlessly supporting all major UI libraries, making it an ideal choice for long-term maintainability and flexibility.

Key results: Astro for the win 🚀

Our analysis revealed significant improvements in Core Web Vital scores across various devices following the migration. Data from our A/B split test post-Astro rollout demonstrated a measurable impact on user engagement and performance:

• +5% improvement in conversion rate

• +8% improvement in abandonment rates

• +10% improvement in add-to-cart rates

These results highlight the tangible benefits of the migration, enhancing both site performance and overall eCommerce effectiveness.