Multi-Tenant Dealer Portal — 200+ Location Rollout

A major European automotive group was running its entire dealer network on a PHP 7.1 portal built in 2011. Twelve years of feature accretion had turned a simple inventory tool into a 340,000-line monolith that nobody fully understood, sitting on a single bare-metal server in a German data centre. With 200+ dealerships across the UK, Germany, France, and the Netherlands relying on it for inventory management, lead routing, and parts ordering, the technical debt had quietly become an existential business risk. The breaking point came during a January peak — a hardware fault at the data centre took the entire dealer network offline for four hours during one of the busiest trading days of the year. The engineering team's post-mortem was brutal: the architecture made redundancy impossible without a full rebuild. The business had been one disk failure away from catastrophe for years. The group's digital transformation director hired us with a clear mandate: build a replacement that can run 200+ dealerships in production within five months, migrate every dealership without business disruption, and leave behind a codebase the internal team can actually maintain.

• Page loads of 8.2s average, spiking to 15s+ under peak — dealers were abandoning sessions mid-workflow and phoning head office instead
• No API layer whatsoever — all third-party integrations (DMS systems, manufacturer feeds, finance platforms) ran on manual CSV imports processed weekly by a part-time contractor
• Zero automated test coverage — every deployment required a 6-hour maintenance window, two engineers on standby, and a prayer that nothing broke
• Single-server architecture with no redundancy — one hardware fault took down all 200+ dealerships simultaneously, as proven in January
• Five different legacy permission models bolted together over 12 years — nobody could confidently answer 'who can see what data'

We designed and built a modern multi-tenant enterprise portal from scratch, migrating all 200+ dealerships with zero business disruption using a phased rollout with feature flags and a live parallel-run period. The architecture was designed for the group's next decade, not just to replace what existed.

• Multi-tenant Next.js frontend with per-dealership configuration, white-labelling, and a clean 5-tier RBAC model (group admin → country admin → dealership manager → sales exec → service technician)
• Node.js/Express API layer with 500+ documented endpoints — real-time inventory sync, lead routing engine, parts ordering, and a webhook system so any future integration can be built without touching core code
• Event-driven architecture using AWS SQS/SNS for all async processing — the weekly CSV contractor was made redundant on day one of go-live, replaced by real-time feeds
• AWS ECS auto-scaling with multi-AZ deployment, CloudFront CDN, and blue-green releases — the January outage scenario is now structurally impossible
• Playwright E2E test suite covering all 47 critical business flows; GitHub Actions CI/CD pipeline that deploys to production in 7 minutes with automatic rollback on health check failure
• Phased rollout over 8 weeks: dealerships onboarded in batches of 25, with the legacy system running in parallel until each batch confirmed full operational handover