Re-platforming a High-Traffic B2B SaaS to Next.js App Router with Zero Downtime.
Migrated a mission-critical multi-tenant SaaS dashboard from a legacy PHP/jQuery monolith to modern Next.js, Docker, and Supabase RLS, boosting Google Core Web Vitals to 99/100.
Google Lighthouse desktop and mobile scores increased from 42 to 99.
Server-side edge rendering reduced initial page load times by over 80%.
Full cutover completed over 6 weeks with zero interruption to active billing subscribers.
The Context & Initial Architecture
A B2B analytics platform with 18,000 active business accounts was suffering from bloated bundle sizes, slow page loads, and fragile release pipelines that caused frequent partial outages.
The Technical Bottleneck & Constraints
The replatforming had to take place with zero customer downtime, maintaining active session authentication and backward compatibility for existing customer API integrations.
System Design & Implementation Flow
Implemented a strangler-fig migration pattern using Cloudflare edge routing to progressively migrate routes to Next.js App Router while running parallel security tests on every deployment.
1. Edge Routing & Session Bridging
Cloudflare Workers routed traffic between the legacy monolith and new Next.js microservices based on route prefixes while sharing encrypted JWT session cookies.
2. Zero-Trust PostgreSQL Data Isolation
Migrated database tables to a unified PostgreSQL cluster with Row Level Security ensuring airtight tenant isolation.
3. Automated GitOps Blue/Green Deployments
GitHub Actions CI/CD workflows run full test suites, automated bundle analysis, and deploy to Docker containers behind health-checked load balancers.
“The migration went off without a hitch. Our page speeds are blisteringly fast, our churn dropped, and our developers can finally ship features in hours instead of weeks.”
Kaitlyn Chen
Co-Founder & CTO, OmniMetrics
Technologies Utilized
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