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Ivan Sapronov
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Ivan Sapronov

Track record

CV on request

I started with a freelance CRM in 2021; since then I've built Kotlin microservices and worked on a platform serving around two million users. Each position lists what I owned and what changed.

  1. Years: 2026Company: CreativeDockRole: Kotlin Backend Developer · contractShipped: 3 greenfield services
  2. Years: 2025–26Company: NCR VoyixRole: Senior Fullstack EngineerShipped: BFF over up to 8 services · ~2M users
  3. Years: 2024Company: CCA GroupRole: Fullstack EngineerShipped: form engine · p95 latency approximately halved
  4. Years: 2022–24Company: AbleneoRole: Software EngineerShipped: Keycloak · Kafka · K8s
  5. Years: 2021–22Company: Voda HoryRole: Java Developer · contractShipped: CRM + analytics

Positions

  1. Apr 2026–Jun 2026

    3 mos

    Kotlin Backend Developer

    CreativeDock · Freelance · Prague, Czech Republic

    A three-month freelance engagement: greenfield Kotlin microservices and the CI and deployment plumbing they shipped through.

    • Built three Kotlin/Spring Boot microservices from scratch (ticketing, booking and subscription), defined their APIs and contracts, and led the architecture decisions for the 3-month engagement
    • Wrote integration tests against real dependencies with SpringMockK and Testcontainers
    • Stabilised and scaled an existing GitLab CI pipeline: diagnosed stalled builds and expanded runner capacity, cutting build queue times from hours to minutes, and added a dedicated build-verification phase
    • Operated and monitored Kubernetes workloads through Argo CD, using automated sync to keep deployments consistent with desired state
    • Shipped improvements to running production services in an existing AWS environment (S3 for images, SQS for messaging, CloudWatch for logs)
    • Kotlin
    • Spring Boot
    • SpringMockK
    • Testcontainers
    • GitLab CI
    • Kubernetes
    • Argo CD
    • AWS S3
    • AWS SQS
    • CloudWatch

  2. Jan 2025–Apr 2026

    1 yr 4 mos

    Senior Fullstack Engineer

    NCR Voyix · Full-time · Prague, Czech Republic

    Senior engineer on a large distributed retail platform: backend-for-frontend and aggregation services on the JVM, a self-service Angular product for US clients, and production operations on GCP.

    • Designed and maintained Java/Spring microservices, including a Backend-for-Frontend and an aggregator service consolidating data from up to 8 downstream services in a large distributed system
    • Built an Angular platform for dynamic menu customisation that let US-market clients update menus through self-service, replacing a manual update process
    • Built and operated GCP services with full production observability (metrics, logging, alerting) for an enterprise system serving ~2 million users
    • Applied LLM and agentic-AI tooling (including MCP integrations) to automate test scaffolding and internal data lookups
    • Shaped technical direction through code review and architecture input
    • Java
    • Spring
    • Microservices
    • Angular
    • GCP
    • Observability
    • LLM tooling
    • MCP

  3. Feb 2024–Dec 2024

    11 mos

    Fullstack Engineer

    CCA Group · Full-time · Prague, Czech Republic

    Fullstack work across an admin panel and a customer-facing application: a dynamic form engine on the frontend and the Java/Kotlin services behind it.

    • Designed and built a dynamic form engine in Angular with conditional validation, real-time updates and customisable templates, reducing the effort to create new form types from days to hours
    • Developed Java/Spring services for form processing and submission behind REST APIs
    • Moved latency-sensitive backend services from Java to Kotlin and used coroutines to run independent downstream calls concurrently, which roughly halved p95 latency under peak load
    • Built a library of strongly-typed Angular components and shared services used by both the admin panel and the customer-facing app
    • Owned the integration between the Angular frontend and the Spring backend: authentication and versioned REST API contracts documented with OpenAPI/Swagger
    • Java
    • Kotlin
    • Kotlin Coroutines
    • Spring
    • Angular
    • RxJS
    • REST
    • OpenAPI / Swagger

  4. Jun 2022–Jan 2024

    1 yr 8 mos

    Software Engineer

    Ableneo · Full-time · Prague, Czech Republic

    Backend engineering on high-traffic systems: caching and reactive services, identity with Keycloak, Kafka messaging, and the container and observability stack around them.

    • Reduced server load and improved response times for high-traffic applications by introducing Redis caching and a reactive, non-blocking architecture with Spring WebFlux
    • Developed user-management services with Spring Data JPA/Hibernate and integrated Keycloak for Single Sign-On (SSO) and Customer Identity and Access Management (CIAM), standardising OAuth2/OIDC across services
    • Established automated testing with JUnit and Mockito, raising coverage and reducing production regressions
    • Dockerised microservices and deployed them to Kubernetes so each one scales on its own
    • Integrated Kafka for inter-service communication (including custom connectors) and built observability with Grafana, Prometheus and InfluxDB to monitor production health
    • Java
    • Spring WebFlux
    • Spring Data JPA
    • Hibernate
    • Keycloak
    • OAuth2 / OIDC
    • Redis
    • Kafka
    • Docker
    • Kubernetes
    • Grafana
    • Prometheus

  5. Sep 2021–May 2022

    9 mos

    Java Developer

    Voda Hory · Freelance · Prague, Czech Republic

    First professional engagement: a CRM with an admin panel and the analytics services feeding its React dashboards.

    • Designed and implemented a CRM system with an integrated admin panel, developing core backend logic in Java/Spring
    • Built the analytics and reporting services behind real-time dashboards in a React frontend
    • Java
    • Spring
    • SQL
    • React
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