Bohdan S.

🟡 Scaling? I worked on a payment gateway that handles 10.1M transactions a month. Do your API integrations or Stripe fail as your SaaS MVP grows? I'm a Senior Full Stack Developer, 7 years in Stripe Billing and Connect, API integrations, webhooks and Node.js. Cutting a 5,000-user SaaS from 532K lines of code to 80K, shipping a marketplace in 2 months, putting 4 AI providers behind one API: that is my work, from React and Next.js to Node.js APIs. ✅ ABOUT ME Senior Full Stack Developer, web developer and website developer delivering web development, SaaS platforms, marketplaces, Stripe payments and MVP development on React, Next.js and Node.js. 5,000+ users on an EdTech SaaS rebuilt from 532K to 80K lines, under 1% data loss, as a Senior Full Stack Developer on React, Next.js, Node.js and NestJS. Production bugs down 40% and regression testing down 54% on the EdTech SaaS as a Senior Full Stack Developer and Backend Developer on React, Next.js and Node.js. SaaS marketplace MVP in Australia, empty repo to production in 2 months, as a Senior Full Stack Developer on Stripe Billing and Next.js. Connect Express payouts with a 25% platform fee and seller KYC on a SaaS marketplace as a Senior Full Stack Developer and Stripe Payments Backend Developer on Next.js. One adapter for OpenAI, Runway, Veo and Luma, new providers ~70% faster, as a Senior Full Stack Developer on a video SaaS built on React and Node.js. Modbus TCP polling at 100% success across 36,850+ readings in a UK SaaS, weekly manual meter reads removed, as a Backend Developer and Senior Full Stack Developer on Node.js. As a Senior Full Stack Developer, I treat every build as a long-term SaaS asset and stay a long-term partner, with Stripe payments and APIs that hold up when the other side fails. ✅ WHERE I DELIVER BACKEND As a Senior Full Stack Developer, Node.js backend developer and Python backend developer on backend NodeJS, NestJS and Express: backend development of SaaS services, background jobs, scheduled tasks, auth and roles, multi-tenant SaaS logic and audit trails. API DESIGN As a Senior Full Stack Developer on SaaS REST APIs in Swagger/OpenAPI and Postman, with versioning, auth, rate limits and consistent errors your React front end and partners can rely on. DATABASES As a Backend Developer and Senior Full Stack Developer on PostgreSQL, MySQL, Redis and Prisma: SaaS data models, migrations, caching and fast queries. PAYMENTS As a Stripe backend developer and Senior Full Stack Developer on Stripe Billing and Connect: Stripe account setup, Stripe dispute handling, Shopify payment processing, Fintech-grade SaaS payments, payment orchestration, payouts, webhooks, reconciliation and retries. INTEGRATIONS As a WordPress developer, Backend Developer and Senior Full Stack Developer on WordPress backend, WordPress API integrations, AI API integration, Twilio, PSP integrations, device gateways and the third-party APIs your SaaS depends on. FRONT END As a Senior Full Stack Developer, front end developer and Webflow developer on React, Next.js, TypeScript and Tailwind: web design, SaaS dashboards, admin panels and customer portals, with server rendering where SEO matters. AI As a Senior Full Stack Developer on AI features that ship: provider adapters, generation pipelines, summaries and assistants inside your SaaS on React and Node.js. MVP As a Senior Full Stack Developer on MVP development, startup MVP for 2 weeks and mobile app MVP RELEASES As a Senior Full Stack Developer shipping SaaS with Docker, GitHub Actions and Swagger docs for every endpoint. ✅ INDUSTRY IMPACT EdTech SaaS, 5,000+ users: 532K to 80K lines, production bugs down 40%, regression testing down 54%, as a Senior Full Stack Developer on React, Next.js and Node.js. Property marketplace SaaS MVP, Australia: 2 months to production, 25% platform fee, 538 commits, 1,301 tests, as a Senior Full Stack Developer and Stripe Payments Backend Developer on Next.js. AI video SaaS: OpenAI, Runway, Veo and Luma behind one adapter, as a Senior Full Stack Developer on React, Next.js and Node.js. Energy and water monitoring SaaS Platform, UK: 36,850+ readings, as a Backend Developer and Senior Full Stack Developer on Node.js. Field-operations SaaS Platform, UK: 3-person team, 27 of 60 commits, as a Senior Full Stack Developer on React and Next.js. ✅ HOW I BUILD A written plan and estimate before any SaaS code, so you know scope, cost and launch date, as a Senior Full Stack Developer and Backend Developer. A demo every sprint on your Next.js SaaS product, so you see progress and change course, with Stripe payments flows. Stripe payments tested before launch, with webhook retries, so no payment goes missing, as a Stripe Payments Backend Developer. QA and DevOps from my team at LeaSoft when your Next.js SaaS project needs them, so releases stay stable. Free discovery call and consultation with me: tell me what SaaS product you need built and by when.