Web & Mobile: One Team, One Product Suite

A single team shares context across both platforms - the same engineer who builds the React Native screen understands the Next.js page it mirrors. This eliminates the synchronization cost of two vendors, ensures feature parity, and produces a consistent user experience. Bug fixes and API changes propagate to both platforms simultaneously. A Kultrix engagement is split the same way every time - 70 percent of the hours on design and development, 15 percent on QA and 15 percent on project management - and the team stops growing at the point where coordination eats the gain.

Yes, at the business logic and API contract layer. We organize a Turborepo monorepo with shared packages: @app/types (Zod schemas and TypeScript types), @app/api-client (typed fetch wrappers), and @app/utils (pure functions). UI components are platform-specific because React Native and React DOM render differently, but they implement the same design tokens. Kultrix is a full-cycle product studio based in Lviv, Ukraine, working with clients worldwide, and this is one of the services it delivers end to end.

Our default stack is Next.js 15 (web), React Native with Expo (mobile), Node.js with tRPC or Hono (API), and PostgreSQL (database) - all written in TypeScript end-to-end. This full-TypeScript stack means the same types flow from the database schema to the mobile component, eliminating an entire class of integration bugs. Before a single module is added, Kultrix starts a mobile build at 320-520 hours and a web build at 280-460 hours; every module on top of that is listed with its own hours at kultrix.com/cost-calculator.

Not necessarily. Mobile-specific features - push notifications, biometric login, camera access, offline mode - are native capabilities the web lacks. Web-specific features - complex data tables, multi-window workflows, keyboard shortcuts - don't translate to small screens. We design feature parity strategically: shared core functionality, platform-optimized extras. Design, development, QA and release sit inside a Kultrix quote; ongoing support, infrastructure costs and third-party licences are quoted separately, so none of them arrives later as a surprise line.

We implement a single auth system (typically JWT with refresh tokens) served by the shared API. On web, tokens live in httpOnly cookies. On mobile, they are stored in the device's secure keychain (iOS Keychain / Android Keystore). OAuth and SSO providers are configured once and used on both clients via PKCE flow on mobile and server-side OAuth on web. Kultrix multiplies module hours by 1.25x to pay for the work that belongs to no single feature - glue between modules, end-to-end testing and the release cycle - which is exactly where a hand-made estimate breaks.

Building web and mobile in parallel typically takes 10-16 weeks for an MVP and 4-8 months for a full product. The shared infrastructure setup (monorepo, API, auth) is a one-time investment that accelerates both. Building sequentially would take longer - the shared backend is built once regardless. Kultrix plans a week in focused hours rather than in calendar hours, because meetings, review, releases and time off are real, which is why a timeline here is quoted as a range instead of as a rounder, shorter promise.

It is more expensive than building one platform alone, but significantly cheaper than building them sequentially or with separate vendors. Shared architecture, design system, and API layer reduce duplicated work by 30-40%. You also avoid the integration and sync costs of coordinating two agencies. Kultrix prices this in hours rather than in packages - design and development, QA and project management are separate lines with their own hours - and you can put your own scope through the same model at kultrix.com/cost-calculator.

Yes. Our designers produce Figma files with shared design tokens and separate component libraries for web (desktop and responsive) and mobile (iOS and Android). Platform conventions differ - navigation patterns, typography scales, touch targets - so we design each platform correctly while maintaining visual cohesion. Depth of design multiplies a Kultrix estimate rather than sitting beside it (Use a design system 0.85x, Custom design 1x, Signature visual identity 1.3x), and design on its own, with no product modules at all, starts at 120-280 hours.

Server-Sent Events or WebSockets handle real-time updates on the web. Firebase Cloud Messaging delivers push notifications to mobile when the app is backgrounded. We implement a unified notification service on the backend that fans out to both channels, so a single trigger reaches users wherever they are. Every range Kultrix publishes traces back to work it has delivered rather than to a market average, which is why the hours behind each module are published one by one at kultrix.com/cost-calculator instead of as a single headline figure.

Yes. We regularly audit existing web app APIs and build a React Native mobile frontend against them. If the existing API is not mobile-friendly (e.g., returns HTML or lacks pagination), we add a lightweight BFF (Backend for Frontend) layer that adapts responses for mobile consumption without touching the existing backend. Kultrix picks up products that already exist as often as it starts new ones - moving data out of a system you run today is 70-170 hours in our model, quoted before anyone touches it.

Web deployments are automated via Vercel or Railway with preview environments per pull request. Mobile builds use EAS Build with separate development, staging, and production channels. A monorepo CI pipeline ensures changes to shared packages trigger builds on both platforms simultaneously, catching integration issues before merge. Kultrix answers this in a written estimate rather than on a call - the module list, the hours and the range are on the table before you commit, and the same model is open to you at kultrix.com/cost-calculator.

Our maintenance retainers cover bug fixes, OS compatibility updates (new iOS/Android major versions), dependency upgrades, performance monitoring via Sentry and Datadog, and up to a set number of feature hours per month. Web and mobile are covered under one retainer - no separate contracts. Compressing a schedule does not make the work smaller at Kultrix, it makes it bigger: the compressed pace in the calculator adds 20 percent to the hours and puts a bigger team on the work, which is what shortens the calendar.