Stanislav Temchenko, Developer in Dnipro, Ukraine
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Stanislav Temchenko

Verified Expert  in Engineering

Software Developer

Dnipro, Ukraine
Toptal Member Since
May 31, 2022

Stanislav is a passionate software developer and technical lead with five years of experience. Skilled in creating architecture from the ground up, migrating projects to the cloud, and redesigning existing systems, he is enthusiastic about programming and product development. Stanislav easily adapts to new technologies and environments, always keen to take on new challenges and leadership responsibilities.


Java, PHP, Amazon Web Services (AWS), Amazon DynamoDB, Amazon ElastiCache...
Java, Spring, Spring Boot, Spring Cloud Stream, Apache Kafka, Apache Beam...
Java, Spring, Hibernate, Elasticsearch, Apache Cassandra, MySQL, Git, Bash...




Preferred Environment

MacOS, IntelliJ IDEA, Git, Apache Maven, Gradle, Docker, Kubernetes, Apache Kafka

The most amazing...

...thing I've designed and implemented from zero to production is an enterprise component that decreased response time from 15 seconds to 400 milliseconds.

Work Experience

Senior Cloud Developer

2022 - 2022
  • Improved third-party transaction performance by adding a cache layer.
  • Discovered and fixed bugs using Jira as a reporting tool.
  • Improved the system design and contributed to organizational planning and team meetings.
Technologies: Java, PHP, Amazon Web Services (AWS), Amazon DynamoDB, Amazon ElastiCache, Spring, Spring Boot, Spring Cloud, Amazon EKS, REST APIs, API Integration, Microservices Architecture, Microservices, RESTful Services, Distributed Systems, APIs, JSON

Java Technical Lead

2020 - 2021
  • Led a team of three back-end developers, conducted meetings with architects and stakeholders, and made a project demo.
  • Decreased an application's response time from 15 seconds to 400 milliseconds by redesigning the data schema and creating asynchronous data processing for batch operations.
  • Reduced Kafka storage by 30% and increased network throughput by 40% using Confluent Schema Registry with Apache Avro.
  • Designed and implemented batch processing for the application component with high memory utilization while reducing used memory by 80% for back-end services.
  • Mentored junior and mid-level back-end engineers—one of them was promoted to senior developer.
  • Conducted meetings and taught about Apache Beam and Google Cloud Dataflow engine technologies.
Technologies: Java, Spring, Spring Boot, Spring Cloud Stream, Apache Kafka, Apache Beam, Google Cloud Platform (GCP), Google Kubernetes Engine (GKE), Cloud Dataflow, Spring Data JPA, Google Cloud Spanner, Git, Jenkins, Gradle, Apache Maven, Confluent Schema Registry, Apache Avro, REST APIs, API Integration, Microservices Architecture, Microservices, RESTful Services, SQL, Distributed Systems, CI/CD Pipelines, Cloud Migration, Amazon Web Services (AWS), APIs, JSON, Migration

Java Software Engineer

2019 - 2020
  • Optimized the speed of Elasticsearch queries by 40% and reduced the Elasticsearch load cluster by 15% using filtered queries, denormalizing documents, and removing aggregations.
  • Investigated and optimized G1 garbage collector performance using JProfiler and VisualVM, which reduced stop-the-world (STW) pauses by 80 milliseconds and CPU utilization by 20%.
  • Wrote a proof of concept to move 10GB of cached JSON files on disk to Redis cache, which improved the response time of every request by 100 milliseconds and reduced the application startup time by 10 minutes.
Technologies: Java, Spring, Hibernate, Elasticsearch, Apache Cassandra, MySQL, Git, Bash, Amazon EC2, Vagrant, Docker, FreeMarker, Guava, Apache Tomcat, Jetty, JProfiler, Java VisualVM, Jenkins, Apache ZooKeeper, Google Guice, TestNG, Mockito, WireMock, REST APIs, API Integration, B2B, Microservices Architecture, Microservices, RESTful Services, SQL, Distributed Systems, CI/CD Pipelines, Cloud Migration, Apache Solr, Amazon Web Services (AWS), APIs, JSON, Migration

Java Software Engineer

2018 - 2019
  • Developed connectors for 30+ cryptocurrency exchanges and algorithms for concurrent trading on 100+ pairs.
  • Fixed bugs, wrote project documentation, and helped to collect and analyze data.
  • Wrote back-end part of the dashboard for metrics monitoring using MongoDB as storage.
Technologies: Java, Spring, MongoDB, Hibernate, JAX-RS, JUnit, Mockito, WireMock, REST APIs, API Integration, RESTful Services, SQL, Distributed Systems, APIs, JSON, Migration

Full-stack Software Engineer

2017 - 2018
  • Developed an online platform for JavaScript games, hosting back-end and front-end parts.
  • Debugged integration problems and ensured code coverage with tests.
  • Deployed the application on-premise to the client's servers and monitored the application status and user activity.
  • Designed and implemented new features from zero to production deployment.
Technologies: Java, JavaScript, WebSockets, SockJS, STOMP, Spring, Spring Boot, Spring Security, Spring Data, JUnit, Hibernate, MySQL, Redis, RabbitMQ, Thymeleaf, Apache Tomcat, Apache Maven, Git, Bootstrap, jQuery, REST APIs, API Integration, HTML, CSS, RESTful Services, SQL, APIs, JSON

User-generated Content Aggregator

The high-load application handled 25 million requests per second (RPS) for gathering user content and delivering it to customer websites. It was written in Java, Python, and Scala.

I contributed as a back-end developer in one of the 40 teams handling the API, which was the most loaded part. We helped the front-end team with integrations. I improved project stability, configured garbage collection that reduced response time by 30%, resolved critical bugs, and covered a significant portion of the project with tests. I also wrote two proof of concepts for object storage and memory optimization while helping with the API documentation and system design initiatives. I configured the SSL certificates for local and production environments.

AWS Certified Cloud Practitioner

Amazon Web Services


Oracle Certified Associate



REST APIs, Guava, JAX-RS, SockJS, jQuery


Apache Maven, IntelliJ IDEA, Git, Apache Beam, Cloud Dataflow, Java Garbage Collection, Apache Tomcat, RabbitMQ, Apache Solr, Gradle, Amazon ElastiCache, Amazon EKS, Google Kubernetes Engine (GKE), Jenkins, Apache Avro, AWS IAM, Amazon Elastic Container Service (Amazon ECS), Amazon Simple Notification Service (Amazon SNS), GitHub, Amazon CloudFront CDN, AWS CloudFormation, Vagrant, FreeMarker, Jetty, JProfiler, Java VisualVM, Apache ZooKeeper, WireMock


Spring, Spring Boot, Spring Cloud Stream, Hibernate, Swagger, JUnit, Mockito, Google Guice, TestNG, Spring Security, Thymeleaf, Bootstrap


Java, SQL, JavaScript, HTML, CSS, PHP, Java 8, Bash


Microservices Architecture, Microservices, B2B, REST, STOMP


MacOS, Amazon Web Services (AWS), Docker, Kubernetes, Apache Kafka, Google Cloud Platform (GCP), Amazon EC2, AWS ALB


Spring Data JPA, JSON, Amazon DynamoDB, Google Cloud Spanner, Amazon S3 (AWS S3), Elasticsearch, MySQL, H2, MongoDB, Spring Data, Redis


API Integration, RESTful Services, Distributed Systems, Cloud Migration, APIs, Migration, Spring Cloud, CI/CD Pipelines, Confluent Schema Registry, Apache Cassandra, Amazon Route 53, SSL Certificates, WebSockets, Healthcare Services

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