Freelance Integration Engineer · Germany
I’m a freelance senior integration engineer. I help companies design, build and run their integration landscape – with TIBCO, Apache Camel and Spring Boot, and messaging on Kafka, ActiveMQ or TIBCO EMS.
Services
From a single interface to migrating an entire middleware platform: I support your team on a project basis, remotely, with hands-on experience from banking, telecoms and energy.
I connect business applications, ERP and core systems through a central integration layer – with clean mapping, clear error and retry handling, and a data flow you can trace end to end.
What you getData arrives complete, and failures surface instead of disappearing silently.
Design and implementation of REST and SOAP interfaces based on OpenAPI or WSDL and XSD, with versioning and well-defined error behaviour. Bridging the REST and SOAP worlds is part of it too.
What you getStable contracts between systems instead of dependencies on internal details.
Replacing proprietary middleware with open-source platforms such as Apache Camel, Spring Boot and ActiveMQ – step by step, with a controlled cutover. Platform migrations, such as AIX to Linux, as well.
What you getLower licence costs and a platform your own team can evolve.
Asynchronous communication with Kafka, RabbitMQ, ActiveMQ, JMS and TIBCO EMS: queues and topics, retries and error queues, so no message gets lost under load or during an outage.
What you getDecoupled systems that deliver reliably under load.
Integration services built with Java, Spring Boot and Apache Camel – tested with JUnit, built with Maven or Gradle, and run on Docker or OpenShift.
What you getMaintainable code your team can take over and extend.
Administration of TIBCO BusinessWorks and EMS across every stage up to production, deployment automation, monitoring with Dynatrace, TIBCO Hawk or Grafana, and incident and root-cause analysis.
What you getStable production and a shorter path from symptom to root cause.
Technologies
Tools I have used on client projects, grouped by where they fit.
The TIBCO product family and Apache Camel for routing, transformation and connectivity.
Message brokers and standards for asynchronous communication.
API contracts, data formats, transformation and tokens.
Services, frameworks, builds and tests.
Relational databases and data access from Java.
Deployment, runtime environments and version control.
Server operations and automation with shell scripting.
Monitoring, logging and troubleshooting in production.
Vendor names describe project experience. They do not imply a partnership, a licence or a certification.
About
I’m Mesut Cetinkaya, a freelance senior integration engineer and administrator specialising in middleware. I design, build and run the integration solutions that let business systems exchange data reliably – with TIBCO, Apache Camel, Java and Spring Boot.
My project experience comes from business-critical environments: TIBCO administration in banking at Akbank; middleware development in the EAI team at Vodafone Turkey, including billing and charging, dunning and consulting on TIBCO upgrades; and rebuilding a complete middleware platform on open source at Medaş.
Beyond development, I have led a development team, mentored junior developers and trained operations teams in TIBCO and Smarttrace. I have been in the room during critical production incidents and know what matters then: narrowing down the cause, stabilising systems and communicating clearly. Today I work as a freelancer under the name Maystro Integration, remotely from Lahnstein.
Approach
A proven sequence, adapted to your project – agile in sprints or planned up front.
Together we clarify which systems are involved, which data needs to flow and where things break today – including the failures that actually occur in production.
Interfaces, message formats, and retry and error scenarios are defined and documented before the build starts.
With the technology that fits your landscape: Java and Spring Boot, Apache Camel, TIBCO or your existing APIs.
Business test cases, malformed messages and the odd formats you meet in practice. Mismatches show up in the test environment, not days later in production.
Monitoring and logging are part of the delivery. With documentation and knowledge transfer, I hand the solution over to your team.
Projects
A selection of past projects, and the kind of work I regularly support companies with.
From my work as an integration engineer in banking, telecoms and energy.
Medaş · Energy
A turnkey rebuild of the middleware layer, replacing the licensed TIBCO platform with Java, Apache Camel, Spring Boot and ActiveMQ on Docker Swarm, Portainer and Nginx. I led the development team, mentored junior developers and was part of the architecture and design team. We owned everything from platform setup and around 80 microservices (REST, SOAP, JDBC, JMS, SFTP, SMTP) to configuration management, documentation and client training. The result: middleware with no licence costs, including container orchestration.
Vodafone Turkey · Telecoms
Middleware development in a cross-domain modernisation programme serving more than 30 million mobile customers. With the middleware connecting almost every system involved, it was critical to the programme. As a senior integration developer in the EAI team I built new services – Java, Apache Camel and Spring Boot microservices on OpenShift as well as TIBCO SOA services – analysed defects in test and production, supported testing and contributed to design and architecture decisions.
Vodafone Turkey · Telecoms
Design and architecture of the new middleware layer and its services in the dunning modernisation project. The system runs the whole process after an unpaid bill: SMS and email reminders, call barring and line suspension, late-payment interest and handover to debt collection. Built with Java, Spring Boot and Apache Camel on Docker Swarm, plus TIBCO EMS.
Akbank · Banking
Member of the TIBCO administration team for the middleware behind mobile, branch and internet banking, handling thousands of transactions per second. Installation, maintenance, upgrades and deployments from development through to production, support for development teams, monitoring and root-cause analysis, plus automation and alerting with Java and shell scripting. Migrations included moving TIBCO from AIX to Linux with a version upgrade, relocating the entire middleware to a new network environment and moving Oracle Service Bus services to TIBCO. Part of the incident response team during critical outages.
Use case
A new service speaks REST while the existing system expects SOAP – or the other way round. Translating contracts, faults and formats happens once, in the middleware, not in every caller.
Use case
Processes that run at different speeds communicate through a message broker. Delivery, retries and queues you can inspect are part of the solution.
Use case
Two business applications need each other’s data but should not read each other’s tables directly. A lean, versioned API contract keeps that boundary.
Use case
Many small services only become manageable once it is clear who calls whom, what happens when one fails, and how you spot that in monitoring.
Use case
Older platforms often stay in production while everything around them is rebuilt. The integration has to cope with the formats and runtimes the existing system dictates.
Use case
When a message does not arrive, its path must be traceable: entry, transformation, exit, error. Monitoring is part of the interface, not a dashboard bolted on later.
Have a similar task? A short description by email is enough for a first assessment.
Contact
Briefly describe your system landscape and what you need – a new interface, a migration or a problem in production. I’ll get back to you with a first assessment.
Remote from Lahnstein, Germany