Sebastian Mihalache

Architected and built the software platform and cloud infrastructure behind the Ville de Lausanne Vélobox program, delivered end-to-end for an enterprise public-sector client.

• →City-wide platform for 1,000 bike-parking spots. Jan–Aug 2026: 1,600+ registrations, ~300 active subscribers and 24,500+ app unlocks.
• →Designed an 11-state subscription lifecycle and a concurrency-safe waitlist & spot-allocation engine.
• →Enterprise foundations: Worldline payments with verified, idempotent webhooks, PII encryption and role-based access (19 permissions).
• →Production infrastructure: containerized services, GitLab CI/CD with security scans, Grafana/Loki monitoring and 300+ automated tests.

TypeScript, Node.js, GraphQL, PostgreSQL, Next.js, Docker, GitLab CI/CD, Grafana

Co-founded a smart-city startup delivering turnkey bike-parking infrastructure for municipalities and businesses; I lead software and infrastructure.

• →Own the software and infrastructure strategy, turning one-off builds into a reusable product.
• →Led the shift from pilots in Romania, Slovakia and Greece to city-scale contracts such as the Ville de Lausanne.
• →Set engineering standards for a lean team: security scanning, automated testing and AI-assisted development.

Focus — Software architecture, cloud infrastructure, product & R&D leadership

Sole engineer on a bespoke e-commerce platform for a luxury retailer, reporting directly to the CEO.

• →Architected a high-performance headless commerce platform with streamlined discovery and checkout.
• →Integrated Stripe payments and owned technical decisions across security and performance.

Next.js, Strapi, Node.js, Stripe, PostgreSQL

Built web and mobile products for NFT-based event check-ins and rewards.

• →Engineered a WebGL map rendering 100,000+ interactive markers on Uber's H3 grid.
• →Built a reusable SDK over the GraphQL API, shared by the web dashboard and the mobile app.
• →Shipped AI-generated avatars in the React Native app — an early production use of generative AI.

Next.js, React Native, Node.js, Mapbox, WebGL, GCP

Analytics platform and booking app for a modular-workspace company.

• →Increased new sales opportunities by 40% with customer-facing analytics dashboards.
• →Helped drive a 10x increase in business valuation by architecting the IoT data platform.
• →Grew revenue by 18% with an on-demand meeting-room booking app.

Next.js, React Native, Node.js, Ruby on Rails, GCP

Architected and built the software platform and cloud infrastructure behind the Ville de Lausanne Vélobox program — secure, app-controlled bike-parking boxes close to residents' homes — delivered end-to-end for an enterprise public-sector client.

• →Architected and delivered a city-wide platform for 1,000 bike-parking spots. Jan–Aug 2026: 1,600+ resident registrations, ~300 active subscribers and 24,500+ app unlocks.
• →Designed the core domain engine: an 11-state subscription lifecycle state machine and a concurrency-safe waitlist & spot-allocation system, automated through scheduled reconciliation and email/SMS notifications.
• →Built enterprise-grade foundations: Worldline payments with HMAC-verified, idempotent webhooks, field-level PII encryption, granular role-based access (19 permissions), separate resident/staff auth and rate limiting.
• →Delivered the operator back-office for city staff: live parking map with demand heatmap, bulk series importer, issue management, exports and enforcement workflows.
• →Stood up production infrastructure: containerized services behind Traefik, GitLab CI/CD with Trivy scans, InfluxDB/Grafana telemetry and Loki alerts that auto-open ops tickets.
• →Integrated the platform with the connected boxes over MQTT 5 on AWS IoT Core; background retries cut failed unlocks from 5.7% to 0%.
• →300+ automated tests (Jest integration, Playwright E2E) and k6 load tests up to 300 concurrent users.

TypeScript, Node.js, Keystone 6, GraphQL, Prisma, PostgreSQL, Next.js, React Query, Tailwind, Mapbox, Docker, Traefik, GitLab CI/CD, Trivy, Grafana, Loki, InfluxDB, Telegraf, Worldline, Jest, Playwright, k6, MQTT 5, AWS IoT Core

Co-founded Rastel, a smart-city startup delivering turnkey bike-parking infrastructure — smart shelters, a resident mobile app and a resource-management portal for municipalities and businesses. I lead software and infrastructure; my co-founder leads the IoT hardware.

• →Own the software and infrastructure strategy — cloud, backend, web and mobile — turning one-off builds into a reusable product that integrates with our connected hardware.
• →Led the shift from pilot hubs to enterprise, city-scale contracts — from pilots in Romania, Slovakia and Greece to becoming solution provider for the Ville de Lausanne.
• →Technical counterpart for municipalities and partners, leading requirements gathering and solution design for public-sector projects.
• →Drive the R&D roadmap, turning lessons from live deployments into the next generation of the product.
• →Set engineering standards for a lean team, making security scanning, automated testing and AI-assisted development (Claude Code, Cursor) the default.
• →Active in the smart-mobility innovation ecosystem, collaborating with EIT Urban Mobility (an EU body) and pitching at the #GovTechConnect Assembly.

Focus — Software architecture, cloud infrastructure, smart-city platforms, product & R&D leadership

Sole engineer behind a bespoke e-commerce platform for a luxury massage-chair retailer, owning the full lifecycle from architecture to launch and reporting directly to the CEO.

• →Architected a high-performance headless commerce platform tailored to a high-end clientele.
• →Designed product discovery and checkout flows that streamline the path from browsing to purchase.
• →Integrated Stripe payments with a secure backend for reliable transactions.
• →Owned technical decision-making across security, performance and best practices, translating business goals directly into the delivery plan.

Next.js, Strapi, Node.js, Tailwind, Stripe, PostgreSQL

Engineered a WebGL map rendering 100,000+ interactive event markers on Uber's H3 hexagonal grid, letting users check in to real-world events via geolocation and QR codes to earn points and unlock rewards.

• →Kept interaction smooth and real-time at scale using GeoJSON layers for markers and check-ins.
• →Built real-time check-in animations that make every interaction feel live.
• →Led research, architecture and performance optimization, coordinating delivery across the team.

Node.js, ElasticSearch, Next.js, Tailwind, Shadcn-UI, GeoJSON, WebGL, Mapbox, GCP, Figma

Built an NFT management dashboard with wallet integration and real-time analytics for transactions on a custom blockchain.

• →Delivered real-time analytics that gave stakeholders transparency into on-chain activity and supported data-driven decisions.
• →Integrated wallet connectivity so users could view, trade and customize their NFTs securely.
• →Built a reusable SDK over the GraphQL API, shared between the web dashboard and the mobile app.
• →Automated end-to-end testing and delivery with Playwright and GitHub Actions.

Node.js, ChatGPT, Alchemy, Metamask, OpenSea, NPM, Next.js, Tailwind, Shadcn-UI, GCP, Playwright, Github Actions

Designed and built a mobile app for event check-ins, combining NFT rewards and gamification to drive engagement.

• →Made check-ins fast and frictionless with geolocation and QR scanning.
• →Shipped AI-generated avatars personalized from user preferences — an early production use of generative AI and prompt engineering.
• →Crafted an intuitive, animated UI that made event participation more engaging.

React Native, Prompt Engineering, ChatGPT, Animations, Figma

Mobile app for booking modular offices and meeting rooms on demand across the city.

• →Grew revenue by 18% by letting users book or rent meeting rooms on the fly.
• →Boosted brand awareness through a bookable network of modular units at strategic city locations.

React Native, Nodejs, Express, Prisma, Figma

Architected an IoT and analytics platform aggregating sensor data from ROOM's modular phone booths and meeting rooms into customer-facing dashboards.

• →Increased new sales opportunities by 40% with a custom analytics dashboard used by customers and the sales team.
• →Helped drive a 10x increase in business valuation by architecting and implementing the Internet of Things (IoT) platform.
• →Built an online service for order tracking and analytics.

Next.js, React, Ruby on Rails, Node.js, Google Cloud Platform, Cloud functions, Figma

Rebuilt the checkout experience for a global luxury fashion retailer.

• →Made checkout 23% faster and reduced friction by rewriting the checkout flow for performance and maintainability.

React, Formik, Docker, Kubernetes

Banking and investment app helping users control cash flow through budgets, savings goals and asset investments.

• →Cut 2 months from the delivery timeline by stepping up as technical lead and re-prioritizing the team's work around client needs.
• →Reduced time spent on budgeting and investing by 70% by designing a scalable, highly available architecture built on microservices and message queues.

Ruby on Rails, CircleCI, AWS, Docker, Nuxtjs, Microservices, PostgreSQL, Message Queues

Online editor for professional translators with multi-language support.

• →Made the editor 25% faster through intensive refactoring of a legacy codebase, and sped up development by 40% by overhauling how the project was built, compiled and shipped.
• →Boosted translator productivity by 30% by designing a companion app with two-way sync that renders the translated document in real time.

React, Webpack, Jest, ES6, HTML5, CSS3

Suite of apps that accelerates market access for new drugs, replacing a slow and costly manual process.

• →Cut drug-acceptance timelines by months (in some cases years) by researching the market and splitting the business flow into three stages, each served by a dedicated app.
• →Paved the way for expanding the suite by owning a proof of concept with a custom reconciliation algorithm for uploading, reviewing and version-controlling medical documents.

AngularJS, React, Node.js, Express, Jest, CI/CD