Case study
Nettoyage AutomobileYour car like new — without leaving home.
A two-sided marketplace connecting individuals with professional car-cleaning specialists who come to their door. A three-step quote funnel on the client side, a subscription-free pro space on the supply side, and a network of over a hundred local SEO pages — all built from scratch in a type-safe monorepo.
- Role
- Design · Development · Architecture · SEO
- End to end
- Year
- 2026
- Type
- From-scratch two-sided marketplace (TanStack / Hono) · at-home car cleaning
A local marketplace linking individuals and car-cleaning pros.
- At-home service
- 3-step online quote
- Subscription-free pro space
- 100+ local SEO pages
The challenge
A two-sided market to bootstrap at once: on the client side, turning a vague need (“my car is dirty”) into a qualified quote request, without immobilising the car or driving anywhere; on the pro side, convincing detailing craftsmen to join the platform when they already have their habits. That meant two distinct journeys, two narratives, but a single database and a single request flow that cleanly links supply to demand.
A second, defining stake: visibility. At-home car cleaning is a hyper-local search (“interior car cleaning Lyon”). The site therefore had to cover dozens of cities crossed with each service, without duplicating thin content, while staying fast and well-structured for SEO. All on a sound, testable, scalable technical base — not a pile of throwaway pages.
The solution: a local marketplace, type-safe end to end
A conversion-focused public site (quote + local SEO), a professional space to capture supply, and a multi-role back office — all in a monorepo where the data contract is shared from the front end to the database.
Three-step quote funnel
Multi-select services, vehicle make and model, time slot, frequency and photos: a guided journey (service → location → details) that produces a complete, actionable request.
Subscription-free pro space
A landing dedicated to supply: pros receive qualified client requests and freely pick the ones they handle, with no commitment or mandatory subscription.
Programmatic local SEO
Each service (interior, exterior, polishing, ceramic…) crossed with dozens of cities: over a hundred prioritized pages, with indicative pricing, breadcrumbs and per-city proof.
Multi-role back office
A TanStack dashboard separating admin, pro and seller roles, wired to the same API as the public site through a type-safe RPC client.
Eco-friendly positioning
A clear angle on every service: biodegradable products, waterless or low-water washing techniques — a genuine differentiator, not a cosmetic one.
Centralized request pipeline
Every quote request converges into a PostgreSQL database (Supabase) through Prisma, ready to be routed to pros — a single source of truth for supply and demand.
The product
Two journeys built for conversion — the individual asking for a quote, the pro receiving requests — and an SEO mesh that brings in local traffic.
Under the hood
A modern, strictly typed monorepo: public site and dashboard on TanStack Start (SSR, React 19), a single Hono API, and a data contract shared from the front end to the database via a type-safe RPC client. Zod validation at the boundaries, Prisma persistence on PostgreSQL (Supabase), a layered unidirectional architecture.
End-to-end type safety
One type contract links the front end, the Hono API (RPC) and Prisma: change a signature and the compiler flags every call site. Fewer integration bugs, calmer refactors.
Industrialized SEO
Services × cities generated from one template, a prioritized sitemap of over a hundred pages, localized content and structured data — to win hyper-local search.
Layered architecture
A strictly unidirectional flow (frontend → API → business → DTO → database), Pino logging and Playwright tests: a testable, scalable base, not a prototype.
My role
End-to-end design and build of the platform: design, full-stack development, monorepo architecture and SEO.
Design & art direction
A clean, reassuring visual system, a green “eco” identity, components for the site and the dashboard.
Full-stack development
TanStack Start front end (SSR), Hono API, Prisma / PostgreSQL integration and the multi-step quote funnel.
Monorepo architecture
Split into apps and packages, a type-safe RPC contract, strict layers and documented conventions.
SEO
A services × cities architecture, prioritized sitemap, localized content and metadata.
A hyper-local need turned into a platform: a complete quote funnel, a frictionless pro space and over a hundred SEO pages — on a type-safe, testable monorepo base built to grow.