What we learned rebuilding the largest Nordic electronic retail website - Tomas Jansson

Next.js was chosen as a “safe” and “boring” choice for rebuilding the Nordic e-commerce site, since most developers know React and it’s well-suited for static content

Server components and Edge runtime initially seemed promising for performance but led to high costs - they moved back to serverless architecture while keeping static content cached on CDN

Good Core Web Vitals scores were achieved, especially on desktop, through server-side rendering and caching strategies. Mobile performance still needs improvement

Feature toggling was implemented using Edge Config, allowing safe testing in production behind feature flags

Caching is handled in two ways: page cache for static content and data cache for dynamic data, with the ability to selectively revalidate

To sell a rewrite project to management:

• Focus on business problems/value rather than technology
• Get early proof of concept
• Start small with time-boxed trials
• Partner with business-oriented colleagues
• Speak management’s language around costs, revenue, customer experience

Team succeeded with just 6 developers by:

• Focusing on delivering value quickly
• Using Next.js app router and Vercel for deployment automation
• Leveraging server-side rendering for SEO and performance
• Implementing micro-frontends for specific functionality
• Making data-driven decisions on architecture

Key technical decisions:

• Mix of static and dynamic content
• Server components by default
• Selective client-side interactivity
• Route grouping for organization
• Middleware for language handling

Testing in production was enabled through:

• Feature flags
• Preview deployments
• Gradual traffic shifting
• Monitoring and metrics

Vercel provided good developer experience but comes at a premium price - team found the benefits worth the cost for their use case