10/23/2026 updated

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Senior Java, Full-Stack Engineer, Spring Boot , Kafka, AWS, OpenShift, Event-Driven Microservices

Sofia, Bulgaria
Germany +9
info: Germany, Austria, Switzerland, France, Belgium, Denmark, Ireland, Netherlands, Norway, Sweden
Master degree: Computer Science
Sofia, Bulgaria
Germany +9
info: Germany, Austria, Switzerland, France, Belgium, Denmark, Ireland, Netherlands, Norway, Sweden
Master degree: Computer Science

Profile attachments

CV-GerganaKostova-Boeva.pdf
210712_Gergana_Recommendation LetterFv.pdf
RecommendationLetter_GerganaBoeva_1706.docx.pdf

About me

Sr Java Architect & Engineer | Fault Tolerance, AI Productivity | System Design, Resilience & Performance (Kafka, Spring Boot, AWS S3, OpenShift, Vault). Expert in Legacy Transformation, Idempotence, Outbox Pattern, DLQ | FinTech, InsurTech, Logistics. B2B: Remote with rare on-site (1 wk/2 mo).

JMeterJava (Programming Language)DevOpsGradleJUnitPostgreSQLApache MavenMongoDBMySQLOpenShiftOracle DatabasesMockitoPrometheusAngular 2+SeleniumData StreamingTypeScriptMultithreadingSpring CloudAttention To DetailIstioOracle 10g/11gGrafanaSpring BootGitKubernetesSlackFull Stack DevelopmentApache KafkaMicroservices
ARCHITECTURE & DISTRIBUTED SYSTEMS
• High-Throughput Microservices: 10+ years scaling Agile systems for Banking, Fintech, InsurTech & VOD (99.9% uptime).
• Asynchronous Messaging: Transactional Outbox Pattern for zero data loss & strict consistency across domains.
• Fault Tolerance: Built resilience setups via Multithreading, Retry Mechanisms, DLQ & Idempotent Consumers.
• Domain-Driven Design (DDD): Mapping logic via Bounded Contexts and Aggregates.
• Security & Permissions: Modernized Four-Eye Principle permission ecosystem for German banking system.

JAVA ECOSYSTEM & DATABASE TUNING
• Framework Migrations: Upgraded enterprise systems to Spring Boot 3.x using Java 17/21. Resolved complex JPA breaking changes (Timestamp/DateTime to LocalDateTime).
• Database & Query Tuning: Re-engineered 9-table legacy bottleneck into optimized SQL UNION ALL query (latency reduced from 2000ms to 20ms).
• Persistence Layer: Advanced Hibernate/JPA tuning. Migrated Identity to Sequence-based generation (IdClass) for German bank, resolving Second-Level Cache bottlenecks.
• Financial Precision: Portfolio rebalancing & fund switching algorithms leveraging BigDecimal (99.9% rounding correctness).

KAFKA, EVENT STREAMING & CLOUD DEVOPS
• Apache Kafka & Search: Event-driven pipelines & Elasticsearch for banking, VOD, logistics & warehouse fulfillment.
• Multi-Cloud & Deployment: Microservices on Red Hat OpenShift, Kubernetes, AWS (S3) & GCP. Cut downtime by 50% via cloud telemetry.
• Configuration & Security: Secure app configs injected via HashiCorp Vault and/or Keycloak.
• Data Migrations: Reconciliation frameworks verifying 150K+ pension accounts with zero data loss.
• Full-Stack & Databases: Angular, JSP, JavaScript | Oracle DB (11g), PL/SQL, DB2, iBatis, MySQL, MariaDB, PostgreSQL, Liquibase, Flyway.

NSURANCE DOMAIN & GRAPHTALK (GT AIA)
• 13+ Years GraphTalk: Global R&D Contract Domain Lead managing core logic on GraphTalk platform for Tier-1 insurers (Allianz, AXA, PREDICA).
• Core Modules: Individual, open group, and group contract lifecycles, clauses, beneficiaries & calculation rules.
• Healthcare Compliance: Régime Obligatoire (RO), Régime Complementaire (RC), NOEMIE flows & Tiers Payant (TP Card) batch processing.

OBSERVABILITY, TESTING & AI PRODUCTIVITY
• Monitoring & Alerts: Prometheus, Grafana, Graylog dashboards. Automated incident response routing real-time alerts via Slack (improved response from 2 min to 10 sec).
• Load Testing: Stress-test scenarios using Apache JMeter to find thread and memory bottlenecks under high concurrency.
• Team Leadership: Mentored 6 to 8 engineers in Agile teams using Jira/Confluence. Cut onboarding times by 30%.
• AI & Productivity: High-velocity delivery leveraging Claude Code CLI and modern tools to accelerate code refactoring and development.

Experience

Professional experience10+ years
Freelancer since2018

Languages

BulgarianNative speakerGermanBasic knowledgeEnglishFluentFrenchGood

Project history

Senior Java Architect & Full-Stack Freelancer | Distributed Systems Specialist | Principal B2B Consultant

MPNG EOOD

Internet & IT

< 10 team member

Specializing in resolving DB bottlenecks, deep Performance Optimization, strict Idempotency & Fault Tolerance (Outbox Pattern, DLQ) within EDA. Expert in Multithreaded systems, System Design, Resilience & OpenTelemetry (OTel). Proven track record in zero-data-loss transformations, 99.99% uptime & Mentoring teams on concurrency.

? ENTERPRISE PORTFOLIO (B2B via MPNG EOOD):
• Atruvia AG (09/2025–06/2026): Modernized core financial infrastructure & permission ecosystems (Java 17, Spring Boot 3.x/4, Kafka) under strict EU standards. Reduced latency from 2s to 20ms.
• DirecTV (03/2022–01/2025): Built event-driven monitoring pipelines for high-traffic live streaming, maintaining 99.9% uptime (Java 8, AWS S3, Multithreading, Prometheus, Grafana, Graylog).
• Allianz AZPS / GI (11/2018–03/2021): Fine-tuned portfolio rebalancing & fund switching engines via BigDecimal (99.9% precision). Verified 150K+ pension accounts with zero data loss (Parallel to REWE Digital contract).

? INTERNAL R&D LABS (Infrastructure Innovation):
• AI Productivity Lab (06/2026–Present): Evaluating Claude Code CLI to streamline terminal automation and accelerate core codebase refactoring and delivery velocity.
• Cloud Infrastructure Lab (02/2025–08/2025): Advanced research and benchmarking in Kubernetes & OpenShift environments to optimize microservices deployment topologies.
• Event-Streaming Blueprints: Designed secure sandboxes using Kafka, Vault & Keycloak to validate enterprise blueprints.

Senior Java / Full-Stack Engineer

Atruvia AG | via Intway

Banking & Financial Services

• Architected, developed, and scaled core microservices for the Bank-Agency Sourcing Management platform using Java 17 and Spring Boot 3.x (later migrating to Spring Boot 4), aligning systems with strict European financial standards.
• Modernized the critical permission ecosystem using Abstract Factory, Adapter, and Template Method design patterns to significantly improve code maintainability.
• Identified and resolved a complex Hibernate/JPA bottleneck regarding
composite key mappings. Engineered a robust migration strategy from Identity to Sequence-based generation
(IdClass), delivering fully tested scripts to ensure seamless database alignment and long-term schema
stability.
• Decoupled microservices by deploying the Transactional Outbox Pattern to guarantee resilient event-driven data flows and zero data loss.
• Constructed Idempotent Consumers and Dead Letter Queues (DLQ) to safely handle unresolvable asynchronous failures with robust error handling using exponential backoff.
• Optimized backend performance, reducing critical endpoint latency from 2s to 20ms (a 98% reduction), and built telemetry dashboards for rigorous JMeter stress testing.
• Configured secure cloud-native authentication and authorization workflows utilizing HashiCorp Vault and Red Hat OpenShift.
• Contributed directly to foundational technical design decisions while mentoring mid-level team members on concurrency, multithreading, and performance best practices.

Senior Backend Engineer & Tech Lead

DirecTV (via Wiser Technology / Bianor)

Telecommunications

• Formulated core backend services using Java, Spring Boot, REST APIs, and MySQL/MariaDB, successfully increasing daily transaction processing capacity by 25% and reducing API error rates by 15%.
• Designed and executed a high-throughput Event-Driven Architecture (EDA) to collect telemetry and user-interaction data from C++ based Set-Top Boxes (STBs) for automated VOD trailer pushes.
• Built resilient communication channels between backend services and STB clients leveraging optimized HTTP Long Polling under strict network constraints.
• Engineered self-healing recovery loops: Implemented a 3-retry mechanism for technical errors, automatically escalating to a hardware reboot via DT commands, while distinguishing cleanly between Business and Network failures.
• Cluster-Wide Anomaly Framework: For business failures, cross-checked errors across adjacent STBs; if 3 distinct devices failed, a critical incident was raised to fix the root cause before affecting the user experience.
• Developed high-throughput distributed applications leveraging Java 8, Spring Cloud, and AWS S3, implementing concurrent processing and multi-threading solutions to maximize cloud reliability.
• Established deep Observability using Prometheus, Grafana, and Graylog to monitor both Infrastructure (CPU, DB stats, Garbage Collection) and Business KPIs, automating real-time alerting via Slack, email, and 3rd-party systems.

Senior Full-stack Engineer

REWE digital

Transport & Logistics

• Senior Full-Stack Engineer (Permanent Contract, Part-time / 20 hrs week, held in parallel with the Allianz GI B2B contract).
• Full-Stack Ownership & Team Upskilling: Architected the UI for the Warehouse Location Configuration module using Angular and introduced advanced state management; independently upskilled the existing backend engineering team on modern frontend architecture to bridge the cross-functional gap.
• Created and optimized core features for a highly allocated warehouse fulfillment and logistics platform utilizing distributed microservices.
• Built Apache Kafka-based event-driven communication frameworks to automate asynchronous business workflows.
• Deployed, managed, and secured cloud-native services on Google Cloud Platform (GCP) utilizing Kubernetes, Docker, Keycloak, and Prometheus/Grafana, reducing production downtime by 50%.
• Enhanced core backend services using Java 11, Spring Boot, Hibernate, MySQL, and PostgreSQL.

Senior Solutions Consultant

Allianz GI

Banking & Financial Services

• Retained directly as an external B2B Senior Consultant to lead performance tuning and data architecture modernization for mission-critical financial applications.
• Fintech Feature Engineering: Fine-tuned core financial operations, including portfolio rebalancing and fund switching mechanisms, leveraging BigDecimal to maximize mathematical precision and achieve 99.9% rounding correctness across transaction algorithms.
• High-Precision Data Migration: Implemented data reconciliation frameworks that verified accuracy for 150K+ pension accounts during a major international infrastructure migration, ensuring zero data loss and strict schema alignment with new IT vendors.
• Enhanced core backend services using Java 8, Spring Data, Spring Security, Spring MVC, Hibernate, Oracle DB (11g), PL/SQL, and iBatis.
• Modernized and upgraded complex financial reporting engines using BIRT reporting tools, JSP, and JavaScript.
• Managed enterprise deployment pipelines, database schema evolutions, and version control using Liquibase, Jenkins, and Tortoise SVN.

Senior Software Engineer & Team Lead – Java Department

DXC Technology (Former CSC / OBS)

Banking & Financial Services

• Client: Allianz Pension Services (AZPS) | Full-time / Hybrid context (2 weeks on-site per trimester).
• FinTech Feature Engineering: Fine-tuned core financial operations including portfolio rebalancing and fund switching mechanisms, leveraging BigDecimal to maximize mathematical precision and achieve 99.9% rounding correctness across transaction algorithms.
• Core Backend Modernization: Enhanced and refactored business-critical backend services utilizing Java 8, Spring Data, Spring Security, Spring MVC, and Hibernate.
• Database & Financial Reporting: Upgraded legacy data structures and automated reporting engines using Oracle DB (11g), PL/SQL, iBatis, and BIRT reporting tools.
• Team Leadership & Agile Governance: Successfully led and mentored an Agile team of 6 engineers. Conducted quarterly performance reviews, managed code reviews, and reduced developer onboarding time by 30%.
• Deployments & CI/CD: Managed enterprise deployment pipelines, database schema evolutions, and version control using Liquibase, Jenkins, and Tortoise SVN.

Global R&D Contract Domain Lead & Core Insurance Architect & Senior Software Engineer at GraphTalk Department

DXC Technology ( former CSC, former OBS)

Insurance

DXC Technology ( former CSC, former OBS)/ InsurTech & Core Insurance (GraphTalk Department):
• R&D Domain Leadership (GT AIA): Acted as Global R&D Contract Domain Lead; architected and managed the core lifecycle for individual, open group, and group contracts (clauses, beneficiaries, product parametrization) within the GraphTalk platform for Tier-1 insurers (Allianz, AXA, PREDICA, FIDEA, La Luxembourgeoise).
• Product Parametrization & Risk Profiling: Engineered core product configuration frameworks leveraging dynamic Insurance Groups and custom parametrization rules for targeted, risk-tier-dependent subscriptions based on demographic and risk populations.
• Status Origin Framework: Designed a mission-critical framework solving complex dependency links between group contracts and members, guaranteeing precise contextual rights reactivation.
• Cascade Mass Treatment Engines: Implemented high-volume cascade treatment engines for multi-threaded propagation of group contract updates across external interfaces.
• Healthcare Compliance & TP Card: Architected the Third-Party (TP) Card Management system for RAM Gamex & APRIA. Built core batch engines for TP Card data cleansing and status reconciliation via NOEMIE data exchange standards (Régime Obligatoire / Régime Complémentaire).
• Team Governance & Delivery: Spearheaded cross-functional Java and technical teams of 8 to 10 engineers; managed change requests (CR), solution definitions, and high-precision quality gates.

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