Cosmin Mavrichi, Developer in Bucharest, Romania
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Cosmin Mavrichi

Bio

Cosmin is a skilled Kotlin/Java developer with over five years of experience building and optimizing microservices. He has worked with technologies like Kotlin, Java, Spring Boot, PostgreSQL, AWS, Apache Kafka, and Elasticsearch, continually focusing on improving system performance, ensuring reliability, and automating infrastructure. Cosmin has a strong track record in troubleshooting, optimizing code, and delivering efficient back-end and full-stack development solutions.

Portfolio

Health (redacted)
Java, Python, PostgreSQL, Amazon Web Services (AWS), Amazon S3 (AWS S3)...
Endeavor - Streaming DBA Dice Technology
Java, Docker, Amazon Web Services (AWS), Spring Boot, Terraform, Kubernetes...
MIRRIAD
Java, Kotlin, SQL, MySQL, Spring 6, Azure, Elastic, Hibernate, Reactor...

Experience

  • Spring Boot - 6 years
  • Java - 6 years
  • Hibernate - 6 years
  • REST APIs - 6 years
  • Elastic - 4 years
  • Kotlin - 3 years
  • Azure - 3 years
  • Amazon Web Services (AWS) - 2 years

Preferred Environment

Java, Kotlin, Azure, Spring 6, Spring Boot

The most amazing...

...solution I've developed is an AI-powered assistant that streamlines content discovery, improving search efficiency for advertising scenes.

Work Experience

Senior Software Engineer

2025 - 2026
Health (redacted)
  • Designed and implemented a 3-tier hierarchical configuration system with JSONB storage and JSON Schema validation, supporting 100+ configurable parameters per tenant.
  • Developed Auth0 organization sync integration for automated user provisioning and M2M authentication, supporting 5,000+ healthcare partner organizations.
  • Engineered a WordPress to PostgreSQL data migration toolkit, successfully migrating all our legacy data with zero data loss.
  • Implemented Redis caching for business report queries, reducing average report load time by around 70% for frequently accessed datasets.
Technologies: Java, Python, PostgreSQL, Amazon Web Services (AWS), Amazon S3 (AWS S3), Spring 6

Java Developer

2025 - 2026
Endeavor - Streaming DBA Dice Technology
  • Designed and delivered back-end services for a feature on a global OTT platform, enabling editorial teams to manage curated content collections.
  • Managed cloud infrastructure using Terraform and Docker, ensuring consistent and reproducible deployments across environments.
  • Optimized APIs to eliminate unnecessary downstream calls for requests, reducing response overhead and improving endpoint performance.
Technologies: Java, Docker, Amazon Web Services (AWS), Spring Boot, Terraform, Kubernetes, Jenkins, Quarkus, Dropwizard, Amazon DynamoDB, Amazon Kinesis Data Streams, MySQL

Senior Software Engineer

2022 - 2024
MIRRIAD
  • Optimized file copy performance within Azure Blob Storage, reducing the time to transfer a 500 GB file from 50 minutes to one minute by implementing parallel transfer techniques and efficient storage management.
  • Decreased Elasticsearch re-indexing time from 5 to 1.5 hours by optimizing workflows, improving data availability, and enhancing developer efficiency.
  • Developed a Kotlin-based AI-powered assistant, enabling users to search a vast content library and locate advertising scenes efficiently, streamlining the content discovery process.
  • Improved SQL performance for MySQL and Azure SQL, achieving significant query execution efficiency and reducing database load.
  • Managed infrastructure consistency with Terraform, creating infrastructure-as-code pipelines that simplified microservices deployment and scaling.
  • Increased microservices test coverage to 80%, reducing bugs and improving release stability by applying rigorous unit and integration testing practices.
Technologies: Java, Kotlin, SQL, MySQL, Spring 6, Azure, Elastic, Hibernate, Reactor, Spring Boot, JUnit 5, Mockito, Apache Maven, Azure SQL, Terraform, Amazon S3 (AWS S3), Amazon RDS, Amazon Simple Queue Service (SQS), REST, REST APIs, Amazon Web Services (AWS), Microservices, Spring, Google Cloud Platform (GCP), Distributed Systems, Cloud Architecture, Kubernetes, Python, Back-end, Back-end Development, Cloud, Database Integration, Event-driven Architecture, Git, Version Control

Java Software Engineer

2021 - 2022
NatWest Group
  • Built flexible mortgage application microservices in Java, contributing to a high-performing platform for Natwest Bank's clients.
  • Mentored and onboarded new team members, facilitating their integration into the codebase and accelerating their productivity.
  • Identified and resolved critical bugs in mortgage workflows, minimizing system disruptions and improving reliability.
  • Collaborated with cross-functional teams, ensuring timely delivery of key features aligned with client requirements.
Technologies: Java, Spring 6, Spring Boot, Oracle Database, JPA, Spring Batch, Swagger, TeamCity, JUnit 5, Mockito, REST APIs, Microservices, Spring, Distributed Systems, Cloud Architecture, Back-end, Back-end Development, Cloud, Database Integration, Git, Version Control

Full-stack Developer

2021 - 2021
TripAdvisor
  • Implemented a drag-and-drop photo gallery in React, streamlining user workflows for managing image order and enhancing UX.
  • Refactored monolithic architecture into microservices, leveraging Java 11, Jersey, and Swagger to improve scalability and modularity.
  • Optimized PostgreSQL ETLs, reducing execution time by 50%, significantly improving data pipeline efficiency.
  • Enhanced system observability by integrating Prometheus metrics and alerting, improving issue detection and resolution times.
  • Designed and added new Apache Avro schemas to track and aggregate data on ad impacts across the platform, enabling precise insights into their effectiveness.
  • Leveraged Presto to query and analyze ad click data, providing timely insights that informed platform optimization strategies.
  • Created Snowflake dashboards to visualize aggregated data, enabling business teams to monitor key metrics and drive data-driven decisions.
Technologies: Java, JavaScript, React, Jersey, OpenAPI, Apache Kafka, Presto, Hadoop, Snowflake, ETL, JUnit 5, Mockito, Gradle, Swagger, Apache Avro, Prometheus, REST APIs, Microservices, Spring, Distributed Systems, Cloud Architecture, Back-end, Back-end Development, Cloud, Database Integration, Git, Version Control

Java Developer

2020 - 2021
UniCredit
  • Developed a barcode parsing microservice, processing around 3,000 daily requests and replacing legacy systems for improved efficiency.
  • Migrated the exchange rate application from Java 7 to Java 8, introducing new features like a "Happy Hour" exchange rate to attract customers.
  • Automated card team reports, reducing manual effort and improving productivity.
  • Refactored legacy libraries to comply with Java 8 standards, improving code readability and maintainability.
Technologies: Java, Oracle Database, Spring 3, Jakarta EE (Java EE or J2EE), SOAP, REST, Hibernate, Apache Maven, REST APIs, Microservices, Spring, Distributed Systems, Cloud Architecture, Back-end, Back-end Development, Database Integration, Git, Version Control

Java Developer

2019 - 2020
Pentalog
  • Developed a Spring Boot back-end application to manage the internal contractors, adhering to best practices like N-tier architecture and using data transfer objects (DTO) to improve maintainability.
  • Implemented unit testing with JUnit 5 and Mockito, increasing code quality and reliability.
  • Collaborated within Agile sprint cycles, delivering features iteratively and maintaining clear communication with stakeholders.
Technologies: Java, Spring 4, JUnit 5, Mockito, MySQL, Spring Boot, Data Transfer Objects (DTO), Agile, REST APIs, Microservices, Spring, Back-end, Back-end Development, Database Integration, Git, Version Control

Experience

Document Management System

This project involved developing the back end and front end of a document management system for storing and retrieving documents, with advanced search capabilities and user access control. I effectively implemented versioning, file metadata tracking, and user permissions.

Education

2016 - 2019

Bachelor's Degree in Computer Science

Vasile Alecsandri University of Bacău - Bacău, Romania

Skills

Libraries/APIs

REST APIs, Reactor, React, OpenAPI

Tools

Apache Maven, Git, Elastic, TeamCity, Gradle, Terraform, Apache Avro, Amazon Simple Queue Service (SQS), Jenkins

Languages

Java, Kotlin, SQL, JavaScript, Snowflake, Python

Frameworks

Spring 6, Spring Boot, Hibernate, JPA, JUnit 5, Mockito, Swagger, Spring, Jersey, Presto, Hadoop, Spring 3, Spring 4, Spring Batch, Dropwizard

Paradigms

REST, Microservices, ETL, Event-driven Architecture, Agile

Storage

Databases, Database Integration, PostgreSQL, Amazon S3 (AWS S3), MySQL, Azure SQL, Amazon DynamoDB

Platforms

Azure, Docker, Oracle Database, Apache Kafka, Jakarta EE (Java EE or J2EE), Amazon Web Services (AWS), Google Cloud Platform (GCP), Kubernetes

Other

Algorithms, Data Structures, Distributed Systems, Cloud Architecture, Back-end, Back-end Development, Cloud, Version Control, SOAP, Computer Science, Prometheus, Data Transfer Objects (DTO), Amazon RDS, Quarkus, Amazon Kinesis Data Streams

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