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Mika Koivisto Hands-On Solution Architect | Lead Developer | Fintech & API Integration Expert

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Professional Summary

I am a Lead Developer and Hands-On Solution Architect with over 25 years of experience in software development and system integrations, specializing in payments and banking systems for the past 7 years. I have extensive expertise in designing scalable API integrations using technologies such as Vert.x and Java in hybrid cloud environments, with a proven track record of delivering mission-critical solutions that meet stringent regulatory requirements and security standards.

Key Skills:

  • Payments and Fintech: Expertise in PSD2, Open Banking, and regulatory compliance for secure financial systems.
  • Architecting Scalable Systems: Expert in Vert.x, Java, and AWS for building high-performance, cloud-native applications.
  • DevOps and Automation: Hands-on experience with CI/CD, automation tools, and cloud environments.
  • Agile Leadership: Skilled in leading teams and implementing agile methodologies, including Scrum, Kanban, and TDD.
  • API Security and Integration: Specialized in secure API design using OAuth 2.0, JWT, OpenID Connect, mutual-TLS with eIDAS certificates.

Competence

  • Architectural patterns: Microservices, Serverless, Event-Driven Architecture, SOA, REST, n-Tier architectures
  • Programming languages: Java, JavaScript/Node.js, Ruby, Python
  • Frameworks:Vert.x, Spring Boot, OSGi 
  • Cloud and DevOps: AWS, Jenkins, Ansible, Docker
  • Middleware:  Apache Kafka, RabbitMQ (MQTT), ActiveMQ, ServiceMix 
  • API Security: OAuth 2.0, JWT, OpenID Connect, SAML, AWS API Gateway, Apigee, TLS/SSL, Financial API (FAPI), PKI
  • Databases: MySQL/MariaDB, PostgreSQL, DynamoDB, DB2, Oracle
  • Monitoring: Dynatrace, DataDog, Nagios, New Relic, JMX, SNMP, Grafana, Prometheus, OpenTelemetry
  • Agile Practices: Scrum, Kanban, XP, TDD, CI/CD
  • Test automation: Cucumber, RestAssured, TestContainers, Junit, Robot Framework, JMeter, SonarQube, WireMock
  • Home automation: MQTT, Home Assistant

Work Experience

  • Apr 2017 - Present

    OP Financial Group (Contract)

    Lead Developer and Architect, PSD2 APIs Apr 2017 – Present

    • Collaborated with stakeholders, including enterprise architects, security architects, cloud architects, and lawyers, to design and architect the PSD2-compliant payment, account information, and funds confirmation APIs. This ensured full regulatory compliance and adhered to Open Banking standards, which granted OP the distinction of being the first Nordic bank to receive an exemption from fallback channels.
    • Re-engineered the APIs using Vert.x as requirements evolved, transitioning from a mixed technology stack to a standardized one. This resulted in improved performance, scalability, and maintainability, while also creating synergies with other team projects.
    • Took ownership of and consolidated the authorization solutions for web, mobile, and sandbox environments, previously maintained by different teams, into a single unified solution, simplifying maintenance and reducing development overhead.
    • Co-authored the first JWT-based security token for internal API usage, providing a stateless alternative to the existing SAML 2.0 and session-based token systems, facilitating hybrid cloud development.
    • Represented OP in Open Banking Europe technical and functional working groups, contributing to the definition of the OBE directory service.
    • Maintained and operated the production environment, optimizing the solution to be managed by a two-person team, streamlining operations and enabling deployments at any time.

    Lead Developer and Architect, Siirto Payment APIs Sep 2024 – Present

    • Took over as the technical lead on the existing solution, which requires a complete technical overhaul to align with OP’s architectural standards and meet new regulatory requirements.

    Lead Developer and Architect, GovAPI Apr 2020 – Present

    • Provided architectural guidance and conducted code reviews, ensuring the project aligns with OP’s architectural guidelines and requirements.

    Lead Developer and Architect, Daily banking service plans Dec 2023 – Present

    • Took over as the technical lead on the project, providing team guidance and conducting code reviews to ensure alignment with OP’s architectural standards.

    Technologies used: Java 17, Vert.x, Docker, hybrid cloud with AWS, PostgreSQL, Apigee, REST, OpenAPI, JWT, OAuth2.0 with Financial API, OpenID Connect, Dynatrace, TestContainers, RestAssured, Apache Kafka

  • Jan 2017 -

    Freelance

    Worldwide

    Select contract assignments:

    • CA Technologies (USA): Implementation of encrypted token support to Liferay SAML 2.0 provider. Worked with teams in USA and India to integrate the solution to CAs own product.
    • Mondi Group (Austria): Performed performance analysis for a Liferay platform to identify and provide a report with actionable suggestions to fix the issues.
    • OP Financial Group (Finland): Ongoing details above
  • 2009 - 2016

    Liferay

    Senior Software Engineer
    Helsinki, Finland Jun 2014 – Dec 2016

    • Focused on mitigating, preventing, and fixing security vulnerabilities while designing security features for the core platform.

    Senior Software Engineer
    Los Angeles, CA USA Nov 2010 – May 2014

    • Reported directly to the company founder and Chief Software Architect, working closely on key development projects.
    • Lead designer and developer for Liferay SAML 2.0 Identity Provider and Service Provider support, a key feature for enterprise customers.
    • Integration specialist, managing Liferay document library connectors and third-party integrations for SSO (including SAML, SiteMinder, and Facebook) to support secure single sign-on and content management solutions.
    • Trained support staff on troubleshooting, helping improve response times and resolution efficiency.

    Senior Consultant Apr 2009 – Oct 2010
    Frankfurt am Main, Germany

    • Provided architecture consulting, auditing, and solution validation for Fortune Global 500 clients, including Robert Bosch, Vodafone, Barclays, and IBM.
    • Led technical workshops and supported pre-sales efforts, assisting with technical evaluations and solution design.
    • Conducted performance tuning and managed production installations to ensure optimized system performance.
    • Developed custom implementations and contributed to Liferay product development to meet client-specific requirements, including integrations using SAML and Terracotta DSO.
  • 2001 - 2009

    Logica (now CGI)

    Lead Software Architect (2006 – 2009)

    • Technical coordination of architects in several concurrent projects in a named account
    • Provided technical pre-sales support and evaluated technical aspects of RFPs
    • Held architecture and code reviews on regular basis
    • Held developer trainings and mentoring
    • Architected solutions using Liferay Portal and Microsoft Office SharePoint Server
    • Designed integrations using IBM Message Broker, JMS and Web services
    • Setup and maintained continuous integration environment

    Software Architect (2006)

    • Lead Architect in a IBM WebSphere Portal implementation for M-real
    • Lead Developer in a IBM WebSphre Portal implementation for Finnair
     

    Software Designer (2001 – 2005)

    • Developed Portals with Fatwire and Bea Portal for Senate Properties and Finnish Justice Department
    • Lead development of IBM Websphere Portal and IBM Workplace Web Content Management for M-real
    • Developer in a Bea Weblogic and Sybase based client-server application using EJBs for Finnish Customs
  • 1999 - 2001

    Spray Network

    Lead Developer

    • Lead the design and migration of Perl based platform to Enterprise Java platform
    • Designed and developed an email system for 300k active users
    • Designed a mobile content and SMS application platform
    • Designed and developed integrations for eCommerce payment processing
  • 1997 - 1998

    Western Washington University

    Web Technician [Computer assistant IV]

    • Assisted university webmaster with maintenance and development of university website
    • Developed several Perl/CGI based web applications

Certifications

  • Liferay 6.2 Certified Professional Developer
  • Sun Certified Programmer for Java Platform 1.4 [310-035]
  • Sun Certified Web Component Developer for Java 2 Platform, Enterprise Edition [310-080]

Education

  • 2003 - 2009

    Helsinki Metropolia Polytechnic

    Studied information technology with focus in software engineering

  • 1996 - 1998

    Western Washington University

    Studied computer science