Website & Mobile App Development for SaaS

Responsive websites and cross-platform mobile apps with full-stack design, accessible UX, and backend architecture built to scale.

Web and Mobile App Development at HighAppler

HighAppler designs and builds web applications and native iOS and Android apps for US B2B companies and businesses in Bulgaria, from single-page web apps and customer portals to online stores and field apps that work offline. Senior engineers write the frontend in Angular or React, the backend in Java with Spring Boot or in Node.js, and the mobile apps in Swift and Kotlin. You can hire a full team for the whole product, or add 1 to 3 dedicated developers to your own team, on a fixed price or time and materials. Every project ends with a maintainable codebase and a complete handover package.

What Our Web and Mobile App Development Includes

Every web and mobile project covers design, build, testing and launch, with the handover documentation your team needs afterwards.

  • Custom responsive web applications
  • Cross-platform mobile development
  • Progressive Web Apps (PWA)
  • UI/UX design and prototyping
  • Performance optimization

Benefits for Your Web or Mobile Product

  • Cross-platform development reducing time to market
  • Responsive design optimized for all devices
  • Modern tech stack ensuring long-term maintainability
  • Agile delivery with regular demos and feedback cycles

Why Build Your App with HighAppler

HighAppler has delivered two live online stores: the Bratoev Invest platform for trading gold, silver and platinum, and herson.bg, a bilingual cosmetics and perfume store for RUMIONES LTD that HighAppler built end to end, with a server-rendered Angular catalog and prices in euros and leva. Krasimir Bratoev describes a professional, secure and user-friendly website that his customers trust, and Rumyana Serkedzhieva a modern, functional solution tailored to her business. We work Monday to Friday, 10:00-19:00 Bulgarian time (03:00-12:00 US Eastern), about 3 hours of live overlap with a 9-to-5 US Eastern day. The code we write is yours on final payment.

Read the Bratoev Invest and herson.bg case studies

Our Approach to Web and Mobile Development

Every web and mobile project we deliver starts with the same question: what does the end user actually need to do, and what is the simplest, most reliable way to support them? We design responsive interfaces that work on any screen, from kiosk-sized desktop dashboards down to small Android handsets, and we treat performance and accessibility as primary concerns rather than afterthoughts. Our developers are experienced full-stack engineers who write production code in TypeScript, Java, Swift, and Kotlin, and who can move comfortably between Angular and React on the front end depending on what your existing platform calls for. Whether you are starting from scratch or modernizing a legacy product, the result is always a maintainable codebase, clear documentation, and a UX that supports real workflows rather than feature checklists.

How a Typical Web or Mobile Engagement Runs

We typically begin with a one to two week discovery phase, where we map your user journeys, validate technical assumptions, and produce a written architecture proposal that includes the exact component structure, API contracts, data model, and deployment topology. From there we move into iterative two-week sprints with demo-ready builds at the end of each cycle. Stakeholders see working software early and often, which means scope adjustments happen with full context rather than surprise deadlines. We pair every front-end engineer with a senior reviewer, run automated tests on every commit, and ship to staging continuously so QA always has the latest code. By launch, your team has a complete handover package - architecture diagrams, runbooks, deployment guides, and recorded walkthroughs of the codebase.

Web and Mobile Technologies We Use

AngularReactVue.jsNode.jsJava Spring BootSwiftKotlin

Web and Mobile App Development FAQs

HighAppler primarily uses Angular, React and Vue.js on the frontend and Java with Spring Boot or Node.js on the backend, with PostgreSQL for data. The choice follows your requirements and your existing platform, so the code stays maintainable for the team that owns it after handover.

HighAppler builds both: native iOS apps in Swift and SwiftUI and native Android apps in Kotlin and Jetpack Compose, or cross-platform apps in Flutter or React Native when one codebase suits your budget and features better. The recommendation follows your users, their devices and whether the app has to work offline.

HighAppler usually starts with a one to two week discovery phase and then builds in two-week sprints, with a working demo at the end of each. A focused MVP typically takes 8 to 16 weeks of active build time; the timeline for a larger app is set in the written proposal after discovery.

HighAppler prices web and mobile work as a fixed price for well-scoped projects or as time and materials for evolving builds, with senior engineers at $25-$49 per hour and projects starting at $1,000. The cost depends mainly on the scope, the integrations and whether you need a web app, iOS, Android or all three.

The source code and IP that HighAppler writes for your app are yours on final payment, with no licence fee and no lock-in. At launch you also get a handover package with architecture diagrams, runbooks, deployment guides and recorded walkthroughs of the codebase, so any team can continue the work.

Related Services

See our case studiesRead client reviews

Planning a Web or Mobile App?

Tell us what your users need to do. We reply within one business day (Mon-Fri, 10:00-19:00 Bulgarian time), with next steps and times for a free 30-minute discovery call.

Discuss Your App