Custom Software Development for SaaS, Construction and Civic Tech

HighAppler is a custom software development company founded in 2025 and based in Shumen, Bulgaria. Its senior engineers build SaaS platforms, web applications and iOS and Android apps, mainly for US B2B companies, working Monday to Friday, 10:00-19:00 Bulgarian time (03:00-12:00 US Eastern).

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50+Years Collective Experience
EUEngineering team in Bulgaria
3+Industries Served
5/5All 5 published reviews are 5-star

Technologies We Use

JavaTypeScriptJavaScriptPythonC#SwiftKotlinPHPAngularReactVue.jsNext.jsRxJSHTML/CSSSASSTailwind CSSBootstrapAngular MaterialSpring BootNode.js.NETLaravelREST APIsMicroservicesiOSAndroidSwiftUIFlutterReact NativePostgreSQLMySQLMongoDBRedisElasticsearchAWSAzureGoogle CloudDockerKubernetesCI/CDJenkinsGitMavenSeleniumJIRA

How Can We Help You?

We design, build and maintain custom software, from websites and web platforms to SaaS products and native mobile apps.

Web & Mobile App Development

We build responsive websites and cross-platform mobile apps that deliver exceptional user experiences. From UI/UX design to backend architecture, our full-stack team creates fast, accessible solutions built to scale.

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Hosting & Maintenance

Lightning-fast, secure hosting with robust infrastructure. We design for high availability, harden security and monitor your applications 24/7.

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Software Product Development

End-to-end product development from concept to launch. We leverage agile methodologies and modern technologies to build scalable, high-performance software tailored to your business needs.

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Enterprise System Integration

We connect your systems, automate workflows, and eliminate data silos. Our integration solutions enable seamless communication across departments, applications, and data sources.

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Cloud Infrastructure

Scalable, reliable cloud infrastructure with optimal resource allocation. Our cloud solutions deliver high availability, rapid load times, and cost-efficient management as your business grows.

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Security & Compliance

Enterprise-grade security with advanced encryption, multi-factor authentication, and sophisticated threat detection. We protect your sensitive data with continuous monitoring and disaster recovery.

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Why Choose Us

HighAppler is a senior engineering team in Bulgaria that partners with US companies on custom software, SaaS platforms and mobile applications. We focus on industries where reliability matters - construction, civic tech, and SaaS - shaping every engagement around what your business actually needs, not a fixed template.

HighAppler works on two pricing models: a fixed price for smaller, well-scoped projects and time and materials for larger, evolving builds. Senior engineers are billed at $25-$49 per hour, and projects start at $1,000. You get cost certainty where it makes sense and flexibility where the work demands it.

HighAppler builds most focused SaaS MVPs in 8 to 16 weeks of active build time, depending on scope, integrations and the complexity of your domain logic. We build the core features first, then iterate on feedback from real users. Larger platforms with custom infrastructure or compliance requirements take longer; their timeline is set in the written proposal that follows scoping.

HighAppler specializes in construction technology, civic tech and SaaS: software for project and field workflows, public-sector platforms and subscription products that need to scale reliably. Before the company was founded, its engineers helped build a SaaS field productivity platform for construction at PeerAssist; since then HighAppler has delivered the Bratoev Invest and herson.bg online stores and built its own cloud POS, Simplixo.

HighAppler is based in Shumen, Bulgaria, and works with clients internationally: mainly US companies, as well as businesses in Bulgaria and elsewhere in Europe. We work Monday to Friday, 10:00-19:00 Bulgarian time (03:00-12:00 US Eastern), which gives about 3 hours of live overlap with a 9-to-5 US Eastern day. EU data residency is available when you need it.

HighAppler's core stack is Java and Spring Boot on the backend, Angular and TypeScript on the frontend, Swift and SwiftUI for iOS, Kotlin and Jetpack Compose for Android, PostgreSQL and Redis for data, and Docker, Kubernetes and AWS for deployment, with Selenium and Postman in QA. We still choose the stack to fit the project, your performance needs and your team's handover plans, not the other way around.

HighAppler signs NDAs as a standard part of every engagement, and mutual NDAs before any deeper technical conversation, so you can share sensitive context early. For regulated work it designs secure architectures for sensitive data with audit-ready delivery practices, provides preparation support for SOC 2, HIPAA, PCI DSS and ISO 27001 audits and helps with GDPR; certification is issued by your independent auditor.
More answers on pricing, contracts, IP and working hours

How We Work

Five steps from the first call to support after launch.

  1. Discovery

    A free 30-minute call, then a scoping phase that ends in a written proposal with milestones, team, stack and timeline.

  2. Planning

    Architecture, API contracts and the data model agreed in writing before development starts.

  3. Development

    Two-week sprints, with a working demo at the end of each.

  4. QA & Testing

    A second engineer reviews every pull request, automated tests run on every commit, and QA tests the latest build on staging.

  5. Launch & Support

    Deployment and a handover package with architecture diagrams and runbooks, then 24/7 monitoring and maintenance if you keep HighAppler on.

What Our Clients Say

Reviews from business owners and a product executive in the US and Bulgaria who have worked with our engineers.

TJ
Theresa Jutagir
Chief Product Officer, PeerAssist
Expert Java team that delivers on quality and innovation
I worked with many of the HighAppler team when they were part of PeerAssist. They helped to build our SaaS Field Productivity platform. Their expert Java team helped us design and launch a powerful, user-friendly solution that bridges field and office teams - handling document management, procurement, time-and-material tracking, and offline support. I'm thrilled with the outcome and proud to partner with a team that delivers on quality, collaboration, and innovation.
CT
Christina Turner
Owner - Arch Business Resources
Deep knowledge and seamless collaboration every time
Working with this team of professionals has consistently been an outstanding experience. Their deep knowledge and reliability shine through in every phase of a project. Communication is always clear and consistent, which makes collaboration seamless. From system architecture and UX design to scalability, they've delivered high-quality solutions every time. I highly recommend them to anyone looking for a dependable and skilled partner.
PI
Petar Ivanov
Owner - P&D Development LLC
Strong commitment to delivering quality results on time
Their team brought deep technical expertise, clear communication, and a strong commitment to delivering quality results. Together, we successfully executed our project goals on time and with impressive outcomes. We truly value this partnership and look forward to future collaborations.
KB
Krasimir Bratoev
Owner - Bratoev Invest
Professional e-commerce platform for precious metals trading
HighAppler built our online platform for trading investment metals - gold, silver, and platinum. They delivered a professional, secure, and user-friendly website that perfectly represents our business. The team understood our specific industry needs and created a solution that our customers trust and enjoy using.
RS
Rumyana Serkedzhieva
Owner - Herson
A modern, functional solution built for our business
Our work with HighAppler was exceptionally professional and fair. The team helped us build our new website, herson.bg, and communication was fast and clear throughout the process. We received a modern, functional solution tailored to the needs of our business. We recommend HighAppler to anyone looking for a reliable partner for website and software development.
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