Browse categories
Explore
Fiverr Pro
English
$
USD
I will build a backend API with authentication, database, and payments
Oleksii B
About this gig
Already have a frontend, mobile app, or design and need a solid backend to power it?
I build clean, production-ready APIs your frontend can connect to immediately. No hacks, no shortcuts proper architecture that scales as your product grows.
What I deliver:
REST APIs (FastAPI / Node) with JWT/OAuth auth, roles & permissions
Database design, migrations & optimized queries (PostgreSQL)
Payments (Stripe + crypto), webhooks, background jobs & queues
Clean architecture, automated tests & deployment
This gig is for you if:
You have a frontend or mobile app that needs a backend
You're building an MVP that needs real, scalable infrastructure
Your API must handle auth and payments and grow without breaking
I've shipped payment-handling backends with auth, billing and audit logs in production. Every API comes with Postman/Swagger documentation and clear setup instructions.
Send me your endpoints and data model I'll scope it and give you a timeline.
Get to know Oleksii B
Oleksii B
FullStack AI Engineer
- FromLatvia
- Member sinceNov 2023
- Avg. response time1 hour
Languages
English, Russian, Ukrainian, Latvian
I am a Full-stack & AI engineer who ships production systems end-to-end, from LangGraph multi-agent backends to React and Next.js frontends. I have experience building production multi-agent GenAI systems on the Azure AI stack and leading engineering teams to deliver high-traffic white-label trading platforms with zero downtime.
My Portfolio
Other Software Development Services I Offer
FAQ
What do you need from me to start?
Your requirements or a list of endpoints, your data model (or I'll design it), any existing frontend/repo, and which payment or 3rd-party services to integrate. No spec yet? I'll help you define one.
Which stack do you build on?
FastAPI (Python) or Node/Express, PostgreSQL, JWT/OAuth auth, Stripe/crypto payments, Docker. I'll recommend the best fit for your project.
Do I get the source code?
Yes — you own 100% of the code, with Postman/Swagger docs and setup instructions. Deployment is included on Standard and Premium.
