NumiSpark

About

Numispark is a France-based web and mobile development agency. We design, build and maintain custom digital products for clients across France and Europe — mobile applications, booking and marketplace platforms, e-commerce systems and business management tools.

We work with a modern JavaScript stack across mobile and web, and we manage our own production infrastructure. Our engineering culture is remote-first, asynchronous, and built around clear written communication and end-to-end ownership of what we ship.

The Role

We are looking for a Full Stack Developer to build and deliver production applications across mobile and web. You will work across the complete development lifecycle — designing APIs, building cross-platform mobile applications, developing web interfaces, and deploying and maintaining systems in production.

This is a hands-on engineering position with real ownership of features and release cycles. You will see your work reach live users on a short cycle, and you will have meaningful input into technical and architectural decisions.

Key Responsibilities

• Develop and maintain cross-platform mobile applications using React Native for Android and iOS
• Design and build RESTful APIs with Node.js and Express
• Model, query and optimise MongoDB databases for production workloads
• Build responsive web interfaces using React and Next.js
• Deploy and maintain applications on Linux servers using Docker, including CI/CD pipelines, reverse proxy configuration, SSL and database backup procedures
• Manage Play Store and App Store submissions, versioning and release cycles
• Maintain, extend and improve existing production applications
• Participate in code reviews and follow Git-based development workflows
• Communicate progress and technical decisions clearly in written English

Required Qualifications

Experience

• 3–6 years of professional software development experience
• Minimum 2 years of hands-on experience with React Native
• At least one React Native application published on the Play Store or App Store, with a clear description of your contribution

Frontend and Mobile

• React Native — navigation, native module integration, performance optimisation, platform-specific implementation
• React.js — hooks, component architecture, state management (Redux, Zustand or Context API)
• Next.js — SSR, SSG and App Router
• Strong JavaScript ES6+ fundamentals, including asynchronous programming patterns
• TypeScript in production environments
• Firebase — push notifications, analytics and crash reporting

Backend

• Node.js and Express — REST API design, middleware, error handling
• MongoDB — schema design, indexing, aggregation pipelines, Mongoose
• Authentication and authorisation — JWT, OAuth, role-based access control
• Real-time features — WebSockets and Socket.io
• Payment gateway integration — Stripe and Razorpay

Infrastructure and DevOps

• Proficiency on the Linux command line
• Docker — writing Dockerfiles, docker-compose, container troubleshooting
• Demonstrated experience deploying and maintaining applications on self-managed servers
• Self-hosted deployment platforms — Coolify, Dokku, CapRover or equivalent
• CI/CD pipelines with GitHub Actions
• Nginx reverse proxy configuration and SSL certificate management
• Git — branching strategies, pull requests, conflict resolution

Other

• Professional written and spoken English
• Availability for a daily overlap window of 2:00 PM – 7:00 PM IST to align with European business hours

Preferred Skills

The following are not required, but strengthen an application:

Mobile

• React Native New Architecture — Fabric and TurboModules
• Native module development in Swift or Kotlin
• Automated release pipelines with Fastlane or EAS
• Offline-first architecture and local persistence (MMKV, WatermelonDB, SQLite)
• End-to-end mobile testing with Detox or Maestro

Web and Frontend

• Tailwind CSS and modern component libraries (shadcn/ui, Radix)
• Animation and interaction work — Framer Motion, GSAP, Reanimated
• Web performance optimisation — Core Web Vitals, Lighthouse
• Technical SEO fundamentals for Next.js applications
• Accessibility standards (WCAG)

Backend and Data

• Redis for caching and session management
• Job queues and background workers — BullMQ, RabbitMQ
• GraphQL and Apollo
• PostgreSQL and Prisma
• MongoDB replica sets, Atlas administration, aggregation performance tuning
• Automated testing — Jest, Vitest, Supertest

Infrastructure

• Object storage integration (S3-compatible)
• Monitoring and observability — Sentry, Grafana, Uptime Kuma
• Infrastructure automation and shell scripting
• Container orchestration basics — Docker Swarm or Kubernetes
• Database backup, restore and migration procedures at scale

Other Platforms and Tooling

• Flutter
• Shopify theme and app development
• Odoo customisation
• Mapping and geospatial development — Leaflet, Mapbox, MongoDB geospatial queries
• Transactional email and deliverability (Brevo, SendGrid, Postmark)
• AI and LLM API integration in production products
• Working from Figma designs
• Agile delivery with Jira, Linear or similar
• Clear technical documentation writing
• Working knowledge of French

What We Offer

• Competitive compensation of ₹6,00,000 – ₹8,00,000 CTC per annum, based on demonstrated experience
• Fully remote position, open to candidates across India
• Flexible working hours outside the daily overlap window
• International project exposure, working on products for European clients
• End-to-end ownership of features, from design through to production release
• Modern technology stack across mobile, web and infrastructure
• Scope to influence architecture and technical direction
• Continuous professional growth across the full engineering stack

Selection Process

1. Application review
2. Introductory call — 30 minutes
3. Technical assignment — 4 to 6 hours, compensated
4. Live technical discussion — 90 minutes, practical and collaborative
5. Offer

Typical timeline from application to offer: two weeks.