MVP
A first version to validate the idea with real users.
from$5,000
6–8 weeks
- Core features
- Auth and roles
- Admin panel
- Cloud deployment
SaaS, portals, FinTech
Web app development: products people enjoy using
We build complex products with simple interfaces: client portals, SaaS, marketplaces, trading and financial platforms with real-time data.
How we build products
Product discovery
We map the business model, users and flows. The result is a feature map and an MVP you can launch fast.
UX for complex interfaces
Dashboards, tables, filters and forms that are easy to use every day — even with large data sets.
Real-time
WebSocket and streaming: quotes, chats, statuses and notifications update instantly.
Security
Authentication, roles and permissions, 2FA, encryption, audit logs and protection against common vulnerabilities.
APIs & integrations
Payment providers, banks, exchanges, CRM, ERP, OpenAI / Claude API — all connected into one system.
Scalable architecture
Docker, CI/CD, AWS or Hetzner cloud, monitoring and logging — the product grows without a rewrite.
What we build
- Subscription SaaS
- Client portals
- Marketplaces and aggregators
- Trading and fintech platforms
- Internal company tools
- AI services built on LLMs
What's included
- Discovery and specification
- Clickable UX prototype
- UI design and design system
- Front-end and back-end development
- API and documentation
- Automated tests and code review
- Deployment, CI/CD, monitoring
- Handover of code and access
- Post-launch support
How much a web app costs
Price and timeline are fixed in the contract after a free brief.
Product
Best valueA full service with payments, integrations and analytics.
from$9,000
2–4 months
- Subscriptions and payments
- API integrations
- Dashboards and reports
- Automated tests
Platform
Complex high-load systems, real-time and fintech.
from$15,000+
4+ months
- Real-time data
- Microservices
- Hardened security
- Support SLA
Staged payments 40 / 40 / 20Formal contractPay in USD, EUR or UAHYou own the code and access
How we work
1–3 days
Brief & research
We study your business, competitors and goals. Price and timeline get fixed.
1 week
UX prototype
Structure and flows that lead a visitor to a request.
1–2 weeks
UI design
A custom design for your brand on every screen size.
2–6 weeks
Development
Clean code, integrations, SEO foundation, testing on real devices.
After launch
Launch & growth
Analytics, team training, then SEO and product growth.
Our work
Веб-додатокDashboardCustom PHP/JS
TaskFlow Workspace
Project management web app for teams & agencies
Projects, a kanban board, team workload, an events calendar and an activity feed — a workspace for agencies and product teams.
Listings PlatformMarketplaceLead Generation
EquipTrade Hub
Marketplace for heavy equipment & machinery
A listings platform: search by category, make and location, verified dealers and secure inquiries to sellers.
Why clients trust us
We don't promise "#1 in a week". We offer terms that protect your money and your project.
Formal contract
Stages, deadlines, price and warranty — in writing before work starts.
Fixed price
The price doesn't change as long as the scope stays the same.
Staged payments
40 / 40 / 20: you pay for the result of each stage, not everything up front.
12-month warranty
We fix bugs for free for a year after launch.
NDA
We sign a non-disclosure agreement before discussing details.
You own the code
Domain, hosting, repository and admin access are registered to you.
Platforms, technologies and integrations we work with
WordPressWooCommerceShopifyOpenCartReactNext.jsNode.jsLaravelFlutterReact NativeFigmaGoogle Analytics 4LiqPayMonobankWayForPayStripeНова Пошта1С / BASTelegram Bot APIOpenAI / Claude API
Common questions
Didn't find an answer? Message us on Telegram — we reply within an hour during business hours.
Message on TelegramHow much does a web app cost?
An MVP starts at $5,000, a full product with payments and integrations at $9,000, complex platforms and fintech at $15,000. We give an exact estimate after discovery.
Which technologies do you use?
React / Next.js and TypeScript on the front end, Node.js (NestJS) or Python on the back end, PostgreSQL, Redis, WebSocket, Docker, AWS.
Do you sign an NDA?
Yes, we sign an NDA before discussing details. All rights to the code and design are transferred to you.
Can we start with an MVP and grow from there?
That's exactly what we recommend: launch an MVP in 6–8 weeks, collect user feedback and grow the product in iterations.
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Prostir Lab builds SaaS products, client portals, marketplaces, trading and fintech platforms with React, Next.js and Node.js. We have experience with real-time systems on WebSocket streams and integrations with exchanges, banks and AI models.
Tell us about your project — estimate in 24 hours
Free consultation, a work plan and a fixed price. No obligations.