You will get Senior Full Stack Developer for Third-Party API Integration | JavaScript
Rising Talent
Project details
As a Senior Full Stack Developer, I connect your web application to the third-party services it depends on - payment gateways, CRMs, AI providers - without breaking under load. I'm a react developer, web developer, and node.js developer who builds with react typescript on the frontend and backend nodejs on the server, the same stack behind a unified adapter that cut new-provider integration time by ~70% for an AI video platform, plus a payout microservice processing 50K+ transactions a day for clients.
Whether you need a react next.js node.js app wired to Stripe, a CRM, or an ai machine learning API, I design for reliability first: signed webhooks, idempotent retries, reconciliation, and monitoring - not just a demo that works once. I've worked as an ai saas developer building AI-assisted platforms end-to-end, and as a saas developer shipping multi-tenant products from architecture to deployment across fintech, iGaming, and EdTech.
Recent results:
✅ 25% dev-time cut on a merchant portal
✅ 70% faster provider onboarding
✅ 50K+ daily transactions handled reliably.
Message me for a quick scope call before committing to anything bigger.
Whether you need a react next.js node.js app wired to Stripe, a CRM, or an ai machine learning API, I design for reliability first: signed webhooks, idempotent retries, reconciliation, and monitoring - not just a demo that works once. I've worked as an ai saas developer building AI-assisted platforms end-to-end, and as a saas developer shipping multi-tenant products from architecture to deployment across fintech, iGaming, and EdTech.
Recent results:
✅ 25% dev-time cut on a merchant portal
✅ 70% faster provider onboarding
✅ 50K+ daily transactions handled reliably.
Message me for a quick scope call before committing to anything bigger.
Programming Languages
PHP, HTML & CSS, JavaScriptCoding Expertise
Cross Browser & Device Compatibility, PSD to HTML, Performance OptimizationWhat's included
| Service Tiers |
Starter
$840
|
Standard
$1,840
|
Advanced
$2,660
|
|---|---|---|---|
| Delivery Time | 3 days | 7 days | 10 days |
Number of Revisions | 1 | 0 | 0 |
Number of Pages | 1 | 3 | 7 |
Design Customization | |||
Content Upload | - | ||
Responsive Design | - | - | |
Source Code | - | - |
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VH
Valeria H.
Jul 29, 2026
Senior full stack developer skilled in react next.js and stripe integration
Bohdan came on as our senior full stack developer, and from day one his recommendations shaped the direction of our SaaS product for the better. As a saas software developer with strong hands on expertise in React, Node, and AI driven features, he didn't just implement what we asked for - he pushed back where needed and suggested a better architecture that saved us weeks of rework down the line. His advice on how to structure the AI integrations turned out to be exactly right: since going live, we've cut processing time by 36% and improved user retention significantly. If you need a full stack developer who brings real technical judgment to the table, not just code, Bohdan is that person!!!! THANK YOU!
VH
Valeria H.
Jul 16, 2026
[Urgent] Full Stack Developer with react nodejs skills for AI SaaS Fintech Platform - Consultant
I brought in a senior full stack developer with deep expertise in React Node + next.js to help fix a critical issue on our fintech orchestration platform. What stood out immediately was how quickly he diagnosed the root cause of a webhook timeout that was causing duplicate charges, clearly someone who's worked as an AI SaaS developer before and understands how these systems break under real-world load. Within 1 HOUR we had a phased plan: idempotency keys, async webhook handling, and a proper reconciliation process. The fix held up under testing, communication was excellent throughout, and the issue hasn't come back since. Highly recommend Bohdan for anyone running a payments or fintech platform who needs someone who can move fast without cutting corners!!
KK
Kristina K.
Jul 13, 2026
You will get Senior Full Stack Developer for Tech Stack and Roadmap for AI SaaS MVP
Bohdan worked as our Senior Full Stack Developer on the MVP for my AI SaaS platform and the results were excellent. As a Web developer, he’s highly skilled in Next.js/React/Node.js and delivered a scalable stack along with a cost optimal infrastructure setup. Clear communication, realistic roadmap and strong technical judgment throughout. Highly recommend this guy!
About Bohdan
Senior Full Stack Developer React Next.js Node.js / AI SaaS Developer
100%
Job Success
Poltava, Ukraine - 1:48 am local time
"He took our legacy SaaS codebase from 520K lines down to 80K. 400% speed boost in development velocity, with zero downtime for our 5000+ users.", — Founder of EdTech Platform
🏆 Senior Full Stack Developer | 6+ years in Next.js, Node.js, React, Laravel and AI SaaS
ABOUT ME
8+ years and 45+ products delivered as a Senior Full Stack Developer specializing in Platform, MVP, AI-Powered and Web Application delivery on Next.js and Node.js.
$4.2M+ client impact and $1.1M+ direct revenue as a Senior Full Stack Developer working across React, Next.js and Node.js.
22,000+ active users across Web + Mobile products where React frontend paired with Node.js backend lifted engagement by 18-27%.
12,000+ users across Fintech and Payments platforms where a Senior Full Stack Developer's Next.js ownership cut reconciliation time by 40%.
2,600+ completed orders, 520+ registered customers in an Ecommerce and CRM Platform MVP delivered as a Senior Full Stack Developer on Next.js.
90% faster order processing, 80% lower manager workload through workflow automation and React improvements as a Senior Full Stack Developer on Node.js.
1,800+ catalog items, 4-role access, 2.8x operational capacity in a B2B SaaS Marketplace built as a Senior Full Stack Developer on Next.js and Node.js.
5-8 weeks shorter MVP-to-pilot launch, 35% fewer bugs through codebase stabilization and SaaS productionization work as a Senior Full Stack Developer.
$1.1M+ in client revenue as a Senior Full Stack Developer on Next.js and React, 8+ years as a Node.js engineer.
18-27% engagement lift, 30-40% faster cycles, cleaner UX and stronger retention as a Senior Full Stack Developer on React, Next.js and Node.js.
As a Senior Full Stack Developer, I treat every build as a long-term SaaS asset, not a one-off delivery.
✅ WHERE I DELIVER
As a Senior Full Stack Developer on React - 20+ SaaS systems with UI development, dashboards and responsive builds across SaaS Platform, Booking Platform and Ecommerce SaaS products.
As a Senior Full Stack Developer on Next.js - 15+ SaaS launches, 30-40% faster iteration through design-to-code and component work.
As a Senior Full Stack Developer on Node.js - 25+ end-to-end SaaS builds with backend APIs, data architecture and secure, scalable systems from early-stage MVP to live SaaS Platform.
As a Senior Full Stack Developer across React and mobile app builds - UI polish and mobile improvements boosting conversion by 15-22% on SaaS products.
10+ deployed mobile SaaS apps in the App Store and Google Play as a Senior Full Stack Developer.
12-19% better repeat usage through booking, notifications and payments on SaaS platforms built as a Senior Full Stack Developer.
As a Senior Full Stack Developer with Python and Django experience - 12+ backend-heavy SaaS products, 28% lower delivery risk.
As a Senior Full Stack Developer - 6-18 month cycles scaling existing SaaS platforms as a long-term partner, holding 99%+ delivery consistency across distributed SaaS teams on React, Next.js and Node.js.
✅ INDUSTRY IMPACT
Marketplace, B2B SaaS - 55,000+ active listings, 20%+ better lead quality and a 35% increase in conversion rates as a Senior Full Stack Developer on React and Next.js handling $2.3M+ in monthly SaaS transaction volume.
Fintech SaaS, Payment Orchestration, PSP Integrations - 12,000+ transactions processed daily, 500+ merchant accounts onboarded, 25%+ faster settlement and 15% fewer failed payments as a Senior Full Stack Developer maintaining 99.9% SaaS uptime on Node.js.
AI-Powered SaaS - 6+ products deployed, custom AI agents, RAG chatbots, OpenAI and Claude API integrations as a Senior Full Stack Developer on React and Node.js, processing 16,000+ daily prompts and cutting query time by 40%.
Logistics SaaS, ERP - up to 12 hours saved per order cycle, 30%+ faster reporting and a 40% reduction in data-entry errors across 5+ regional hubs as a Senior Full Stack Developer on Next.js.
Fintech SaaS, PropTech SaaS, LegalTech SaaS - 18% better adoption, 40% higher retention over 6 months and structured permissions managing 5,000+ users as a Senior Full Stack Developer on React.
✅ HOW I BUILD
25+ SaaS products as a Senior Full Stack Developer on React: React Native, Next.js, TypeScript, JavaScript, HTML5, CSS3, Tailwind, Responsive Design.
15+ SaaS systems as a Senior Full Stack Developer on Node.js: PostgreSQL, MySQL, MongoDB, Firebase, Stripe, integrations across payment, maps, auth and third-party APIs.
10+ SaaS ecosystems as a Senior Full Stack Developer: WordPress, Shopify, PHP, Flask, Python, Django, MERN stack on Next.js and Node.js.
40+ SaaS products as a Senior Full Stack Developer: Git, software architecture, front-end development with an engineer's mindset applied to every SaaS Platform I ship.
Steps for completing your project
After purchasing the project, send requirements so Bohdan can start the project.
Delivery time starts when Bohdan receives requirements from you.
Bohdan works on your project following the steps below.
Revisions may occur after the delivery date.
Discovery & API review
Review the third-party API docs, test sandbox access, and map out the exact data flow and edge cases before writing any code.
Integration & webhook setup
Build the core integration with signed webhooks, retry logic, and error handling so it keeps working under real-world conditions.