Full Stack Developer (Next.js) BR

About Fluxicart

Fluxicart is a white-label multi-tenant marketplace platform that empowers merchants to create their own fully customized online stores (themes, domains, branding) while operating under a centralized platform that manages payments, deliveries, commissions, and administrative dashboards.

We are building the "Shopify + iFood + Production System" for the European market, starting with Ireland and expanding to Brazil.

Our stack is modern and ambitious:

• Current: Next.js 15 (App Router) + React 19 + TypeScript + Prisma + SQLite/PostgreSQL
• Future: Migrating to microservices with Rust (Axum) + gRPC + NATS + Redis

We are backed by a clear product vision, an active user base, and a roadmap that includes international expansion, WebSocket real-time features, and high-performance Rust microservices.

The Role

We are looking for a Senior Full Stack Developer with deep expertise in Next.js and the modern React ecosystem to join our core engineering team in Dublin.

In this role, you will:

• Build and maintain the monolith Next.js platform that powers the entire Fluxicart ecosystem
• Work across the full stack — from database schema design (Prisma) to React UI components (shadcn/ui)
• Collaborate with product managers, designers, and backend engineers (Rust) to ship features that merchants love
• Contribute to the migration strategy from the Next.js monolith to Rust microservices
• Own features end-to-end: from requirements gathering to deployment and monitoring
• Mentor junior developers and participate in code reviews, architecture discussions, and technical decision-making

You'll have a direct impact on the product and the company's growth — we're a flat team where engineers ship fast, learn continuously, and shape the product roadmap.

Key Responsibilities

Frontend Development (60%)

• Build responsive, high-performance user interfaces using Next.js 15 (App Router) and React 19
• Implement pixel-perfect UI components using TailwindCSS and shadcn/ui (Radix UI)
• Manage state with React Context, Zustand, or TanStack Query
• Implement internationalization using next-intl (English/Portuguese, expanding to Spanish/French)
• Build drag-and-drop interfaces for the Page Builder feature using @dnd-kit
• Ensure accessibility (WCAG 2.1 AA) and cross-browser compatibility
• Optimize for performance: Core Web Vitals, Lighthouse scores >90, ISR caching

Backend Development (30%)

• Build and maintain API Routes (Next.js Route Handlers) for the monolith
• Design Prisma schemas and migrations (SQLite/PostgreSQL)
• Write type-safe queries with Prisma, including complex joins and aggregations
• Implement RBAC (Role-Based Access Control) with middleware
• Build file upload endpoints (S3/MinIO integration)
• Write unit and integration tests using Vitest and Playwright

Architecture & DevSecOps (10%)

• Contribute to the strangler fig migration from Node.js → Rust microservices
• Design APIs with backward compatibility (versioning strategy: v1, v2, deprecation policy)
• Implement caching strategies with Redis (write-through, TTL, invalidation)
• Work with Docker, GitHub Actions, and Kubernetes (EKS)
• Monitor application performance using Prometheus, Grafana, Loki, and OpenTelemetry

Requirements

Must-Have

Requirement Details:

Experience: 5+ years of professional full-stack development.

Next.js: Deep experience with Next.js 14/15, App Router, Server Components, ISR.

React: Expert-level React 18/19, Hooks, Context, Suspense.

TypeScript: Strong TypeScript (strict mode) — interfaces, generics, utility types.

Database: Experience with Prisma ORM or similar (TypeORM, Drizzle).

SQL: Proficient in SQL (PostgreSQL preferred) — complex queries, indexing, performance tuning.

API Design: Experience building RESTful APIs (Next.js API Routes, Express, Fastify).

Authentication: JWT, httpOnly cookies, refresh token rotation, RBAC middleware.

Testing: Unit testing (Vitest/Jest) + E2E testing (Playwright/Cypress).

Version Control: Git, GitHub, PR workflows, CI/CD.

Nice-to-Have

Requirement Details:

Rust: Basic knowledge of Rust (we're migrating!).

Docker/K8s: Experience with containerization and orchestration.

Cloud: AWS (RDS, S3, EKS) or GCP/Azure.

Real-time: WebSockets, Server-Sent Events, or Socket.io.

GraphQL: Experience with Apollo or GraphQL Yoga.

Shadcn/ui: Experience customizing shadcn/ui components.

i18n: Experience with next-intl or similar.

E-commerce: Prior experience in e-commerce, marketplaces, or payment platforms.

Startup Experience: Worked in fast-paced, product-driven startups.