You will get React developer | FastAPI development for scalable SaaS apps
Top Rated
Top Rated
Project details
I build scalable SaaS applications with a focus on clean frontend architecture and seamless backend integration. As a React developer and Agentic AI developer, I create systems that are ready for growth and AI integration.
My expertise in FastAPI development helps ensure efficient communication between frontend and backend, making me a strong web developer and full stack developer. I also work as a Firebase developer, leveraging firestore for real-time features and scalable cloud environments.
With experience as a python developer and app developer, I understand how to structure applications for performance and maintainability. I also consider cross-platform needs like a react native developer and follow patterns similar to a flutter developer when needed.
This service is ideal if you need a full stack developer to build a scalable SaaS product with modern technologies and long-term flexibility.
My expertise in FastAPI development helps ensure efficient communication between frontend and backend, making me a strong web developer and full stack developer. I also work as a Firebase developer, leveraging firestore for real-time features and scalable cloud environments.
With experience as a python developer and app developer, I understand how to structure applications for performance and maintainability. I also consider cross-platform needs like a react native developer and follow patterns similar to a flutter developer when needed.
This service is ideal if you need a full stack developer to build a scalable SaaS product with modern technologies and long-term flexibility.
Programming Languages
JavaScript, Python, TypeScriptCoding Expertise
Cross Browser & Device Compatibility, Localization, Performance OptimizationWhat's included $1,000
These options are included with the project scope.
$1,000
- Delivery Time 17 days
- Number of Revisions 3
9 reviews
(9)
(0)
(0)
(0)
(0)
This project doesn't have any reviews.
OG
Oleksii G.
Jul 20, 2026
Senior React Developer (Node.js, Next.js, Python, AI) - Early-Stage AI Project
Great communication, and we’ve already wrapped up the first small milestone. Thanks, Alex and the Olearis team!
SU
Simon U.
Jun 4, 2026
Code the language learning app LinguaLeap/Disign exists already
Honestly one of the best dev experiences we’ve had on Upwork. Olearis team built our Flutter language learning app and absolutely nailed it. The project wasn’t easy (custom learning logic, gamified flows, tons of interactive screens) and they handled all of it like pros. The team understood what we wanted, followed the designs closely, and was always easy to talk to. They were responsive and really cared about making the product work well. I’d gladly work with them more.
OL
Olena L.
Apr 14, 2026
React Engineer for Platform Audit & Future Collaboration
It was a great experience working with this React Developer and the whole team at Olearis. Communication was smooth and clear, and everything was handled quickly and professionally. They delivered fast and with high quality. Looking forward to working together again in the future.
JW
James W.
Mar 24, 2026
Need : team of passionate, highly experienced web developers (SEO, usability, AI photo editor)
Great job!Thank you for amazing work by olearis team. Great communication and execution! Best of luck :)
JB
Josh B.
Mar 14, 2026
Teamword Game
Olearis was a fantastic partner throughout my work with them. Very responsive, creative, fast and easy to work with. I'd highly recommend them!
About Alexander
Full Stack Developer | AI Developer | React Developer
100%
Job Success
Kyiv, Ukraine - 2:22 am local time
⚛️ React Developer • Full Stack Developer • AI Developer
🔥 𝗖𝗹𝗲𝗮𝗻 𝗮𝗿𝗰𝗵𝗶𝘁𝗲𝗰𝘁𝘂𝗿𝗲, 𝗳𝗲𝘄𝗲𝗿 𝗿𝗲𝗯𝘂𝗶𝗹𝗱𝘀, 𝗳𝗮𝘀𝘁𝗲𝗿 𝗹𝗮𝘂𝗻𝗰𝗵
I'm Alex. I run product delivery at Olearis with a 30-person team, and I help founders and startups ship web, mobile, and AI products that launch on time, scale cleanly, and don't need rebuilding later. As a full stack developer and React developer, I take ownership from idea to production, so you get one accountable partner instead of five contractors and don't pay to fix the same things twice.
📊 𝗥𝗲𝘀𝘂𝗹𝘁𝘀 𝗳𝗿𝗼𝗺 𝘁𝗵𝗮𝘁 𝗮𝗽𝗽𝗿𝗼𝗮𝗰𝗵
12M+ users, that's what we shipped in social mobile products.
1M+ users and a 4.8 App Store rating, that's our AI mental health work.
80+ companies including Bank of America and Citibank trust software we built.
36+ education apps run on AI tutor logic we designed.
🧩 𝗪𝗵𝗮𝘁 𝗜 𝘄𝗼𝗿𝗸 𝗮𝗰𝗿𝗼𝘀𝘀
I lead builds end to end as a full stack developer, web developer, React developer, react native developer, mobile app developer, Python developer, AI Developer, and WordPress developer. 16+ years in production. The rule is simple: build it properly from the start, so your next developer doesn't have to rewrite it later.
🔥 𝗪𝗵𝗮𝘁 𝗜 𝗵𝗲𝗹𝗽 𝘄𝗶𝘁𝗵
⚛️ Frontend & web. As a React developer and web developer, my team and I build SaaS platforms, dashboards, admin panels, marketplaces, and web apps with modern React patterns, clean architecture, Figma-to-code accuracy, and accessibility (WCAG 2.1 AA). React web development done right goes past screens: performance, reusable components, and maintainability.
🧱 Full stack. As the full stack developer owning the architecture, I connect frontend, scalable backend, mobile, Firebase, FastAPI, role-based access (RBAC), OAuth flows, and AI logic into one production-ready system. Whether it's a full stack developer react node build, a python full stack developer setup, or full stack developer php and full stack developer laravel work, you get one owner instead of five.
🤖 AI. On the AI Developer side, we build AI that's useful inside the product: assistants, agentic workflows, AI agent development, LLM integration, recommendations, and AI dashboards. From ai chatbot developer work to ai software developer system design, an AI Developer only earns their place when machine learning features are useful, not just clever in a demo. A data scientist explores the data, a Python developer turns it into services, and an AI Developer ships it, plus power bi developer reporting dashboards.
🐍 Backend & Python. As a Python developer with deep FastAPI experience, I build APIs, integrations, automation, data pipelines, machine learning workflows, and backends that handle real users. If your backend feels fragile, I step in as a Python developer and full stack developer to clean it up: readable, tested, production-ready, easy for the next data scientist or web developer to support.
📱Mobile. As a react native developer and mobile app developer, I build iOS and Android apps that connect cleanly to backends, APIs, subscriptions, payments, and push. A strong react native mobile app developer thinks about performance, release flow, and future support. Need cross-platform? A flutter developer can support Flutter or help you choose the right stack.
🌐 WordPress. As a WordPress developer, I handle marketing sites, landing pages, and CMS builds beside the main product, so your React developer, full stack developer, and WordPress developer work stays one consistent product story.
𝗣𝗿𝗼𝗱𝘂𝗰𝘁 𝗲𝘅𝗽𝗲𝗿𝗶𝗲𝗻𝗰𝗲
🟣 Parlor, social platform, 12M+ users
🟢 UpLife, AI mental health app, 1M+ users, 4.8★
🔵 Notate, secure productivity, trusted by Bank of America & Citibank
🟠 Fillrr, AI document app with smart parsing
🔴 Beatly, SaaS connected to Netflix, Uber, Spotify & 250M+ creators
🟤 HearMeOut, AI 24/7 therapy companion
⚪ Exam Prep Apps, 36+ education apps with AI tutor logic
💰 𝗪𝗵𝘆 𝘁𝗵𝗶𝘀 𝘀𝗮𝘃𝗲𝘀 𝘆𝗼𝘂𝗿 𝗯𝘂𝗱𝗴𝗲𝘁
✅ Clean React developer and web developer work means fewer frontend bugs.
✅ Thoughtful full stack developer work means frontend, backend, and mobile aren't fighting each other.
✅ Reliable Python developer and FastAPI work means a backend easy to scale and monitor.
✅ Good react native developer, flutter developer, and mobile app developer work means fewer mobile fixes after release.
✅ Practical AI Developer, machine learning, and data scientist work means AI features that are useful, not trendy.
📩 Need a React developer, web developer, full stack developer, or AI Developer? Text me and I'll tell you honestly what it'll take.
🔑 Areas: React Developer • Full Stack Developer • AI Developer • web developer • wordpress developer • mobile app developer • react native developer • python developer • machine learning
Steps for completing your project
After purchasing the project, send requirements so Alexander can start the project.
Delivery time starts when Alexander receives requirements from you.
Alexander works on your project following the steps below.
Revisions may occur after the delivery date.
write me first