Lukasz L.

Failed payments, orders out of sync, integrations that break at night? I help e-commerce and SaaS companies build full stack Symfony, Laravel and Node/Next.js apps that don't lose money: payments, marketplaces, ERPs and APIs that just work. Lately, that includes AI: LLM features and agents built into real products, where they have to be as reliable as everything else. I've also run my own businesses: a SaaS product, and a product brand with its own garment production. So I've been on the other side too, dealing with stock, suppliers, deadlines and cash flow, not just code. That's why I'll tell you when a feature can wait, when a simple solution is good enough, and when cutting a corner will cost you later. What clients usually hire me for: ✅ Full stack SaaS products: Symfony/Laravel or Next.js/NestJS/Node.js/TypeScript backends with React frontends, including multi-tenancy, RBAC, and secured REST APIs ✅ AI features in real products: LLM integrations (OpenAI, Claude), AI agents, MCP servers, and workflow automation, built into production systems rather than left as demos ✅ E-commerce integrations: connecting shops and marketplaces with ERPs, WMS and courier/shipping APIs, synchronizing orders, products, stock and prices at scale (experience from Base, one of Europe's largest e-commerce integration platforms) ✅ Payment integrations: Stripe, PayPal, Adyen, PayU, Przelewy24, Solidgate, OPPWA (ACI / Open Payment Platform) and Cryptomus for crypto payments, plus checkout flows, webhooks, refunds and reconciliation, built with security and reliability in mind ✅ IoT and device integrations: receiving and processing data from GPS trackers and other hardware devices, including custom protocols, telemetry pipelines, PostgreSQL/PostGIS geospatial processing and reporting ✅ Rescuing legacy codebases: audits, refactoring, upgrades, and test coverage ✅ Technical leadership: architecture, code review, and guiding teams through critical deliveries How I work: clear communication, small verifiable milestones, clean tested code, and documentation you can hand to the next developer. I use AI tools (Claude, Copilot) daily for reviews, tests, and refactoring, which speeds up delivery without cutting corners. Core stack: TypeScript, Next.js, Node.js, NestJS, PHP 8.x, Symfony, Laravel, Python, FastAPI, Supabase, PostgreSQL/PostGIS, MySQL, Redis, RabbitMQ, Elasticsearch, Docker, CI/CD, Vercel, AWS. Have a product to build, an AI feature to ship, or a codebase to save? Send me a short description, and I'll reply with concrete next steps.