Enterprise System Integration Services

Connect your systems, automate workflows, and eliminate data silos with integrations across departments, applications, and data sources.

Enterprise System Integration at HighAppler

HighAppler connects the systems a business runs on, for US B2B companies and businesses in Bulgaria: ERP and CRM platforms, payment gateways, third-party APIs, legacy databases and custom applications. Senior engineers map the business processes that must flow between systems, agree a written integration design with you, then build it on REST or GraphQL APIs, Kafka or RabbitMQ events and OAuth 2.0, with monitoring that surfaces failures early. Every integration is versioned, tested and documented for the team that maintains it, and knowledge is transferred to your people as the project runs.

What Our Integration Work Includes

Every integration project covers design, build, monitoring and documentation, so the connections keep working after handover.

  • API design and development
  • Third-party system integration
  • Data migration and synchronization
  • Workflow automation
  • Legacy system modernization

Benefits of Connected Systems

  • Eliminate data silos with unified system connectivity
  • Automate cross-department workflows and processes
  • Real-time data synchronization across all systems
  • Future-proof architecture with modern API standards

Why HighAppler for Integration Projects

Before HighAppler was founded, its engineers designed and built a scalable middleware layer for a growing enterprise: an event-driven architecture that connected systems across departments, automated business rules and kept data in sync in real time. HighAppler brings that experience to every integration, starting from the business processes rather than the systems and documenting every assumption about data ownership, transformation rules and error handling before code is written. 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.

Read the enterprise integration case study

Our Approach to Enterprise Integration

Enterprise integration projects fail more often from misaligned expectations than from missing technology. We start by mapping the actual business processes that need to flow between systems - not just the systems themselves - and we document every assumption about data ownership, authoritative sources, transformation rules, and error handling. Once the integration contract is clear we build it on proven middleware: REST and GraphQL APIs for synchronous flows, Kafka or RabbitMQ for event-driven patterns, and OAuth 2.0 for secure cross-system authentication. We treat integration code with the same care as application code: versioned, tested, observable, and documented for the team that will maintain it after we leave.

What an Integration Project Looks Like

A typical integration engagement begins with a one to two week discovery and architecture phase, where we interview both technical and business stakeholders, document the existing systems landscape, and produce a written integration design that everyone signs off on before development begins. Implementation runs in iterative sprints, with each sprint delivering at least one working end-to-end integration flow that can be exercised in a staging environment. We instrument every integration with structured logging, dead-letter queues, and dashboards that surface failures early, so when something goes wrong in production your team has the visibility to fix it quickly. Throughout the project we work closely with your internal teams to transfer knowledge, so by the end you do not just have working integrations - you have a team that understands how they work.

Integration Technologies We Use

Apache KafkaRabbitMQREST APIsGraphQLJava SpringMuleSoftOAuth 2.0

System Integration FAQs

HighAppler integrates ERP systems, CRMs, payment gateways, third-party APIs, legacy databases and custom applications. It works with REST, GraphQL and SOAP interfaces and with event-driven architectures on Kafka or RabbitMQ, and secures the connections between systems with OAuth 2.0.

HighAppler builds adapter layers and middleware that connect legacy systems to modern platforms, so you can modernize step by step without disrupting the operations that depend on them. Every assumption about data ownership, authoritative sources, transformation rules and error handling is documented before development starts.

HighAppler starts with a one to two week discovery and architecture phase that ends in a written integration design everyone signs off before development. Implementation then runs in sprints, and each sprint delivers at least one working end-to-end flow you can exercise in a staging environment.

HighAppler instruments every integration with structured logging, dead-letter queues and dashboards that surface failures early. A message that cannot be processed is kept rather than lost, and your team has the visibility to find the cause and fix it quickly.

HighAppler versions, tests and documents integration code with the same care as application code, for the team that maintains it afterwards, and works alongside your internal teams throughout the project to transfer knowledge. By the end you have working integrations and people who understand how they work.

Related Services

See our case studiesRead client reviews

Systems That Should Talk to Each Other?

Tell us which systems you need to connect and why. We reply within one business day (Mon-Fri, 10:00-19:00 Bulgarian time) and propose next steps.

Discuss Your Integration