Available for work & freelance

Vsevolod Prostyakov

Java / Kotlin / Python Back-End Developer

Back-end developer with 3+ years of experience in FinTech, e-commerce and HRM — 10+ microservices on Spring Boot and Django, banking lending and investment systems. I design services from scratch, build third-party integrations and care deeply about security, performance and clean code.

01 — Contact

Let's build something

Open to full-time roles and freelance projects. The fastest way to reach me is Telegram or email — I usually reply within a day.

02 — About

What I bring to the table

  • Back-end developer in Java, Kotlin and Python — high-load services on Spring / Spring Boot and Django / DRF, designed from scratch: service boundaries, data model, API contracts.
  • REST APIs documented with OpenAPI; event-driven processing with Apache Kafka and RabbitMQ; OAuth2 / JWT auth with custom Spring Security filters and Keycloak.
  • End-to-end integrations with payment, delivery, credit and CRM providers: IPay / WebPay / EPay, Yandex Go, Credit Registry, IDCheck, ERIP, 1C, Bitrix24, QUIK.
  • Database design and query optimisation (EXPLAIN ANALYZE, indexes, N+1 fixes), schema versioning with Liquibase / Flyway and safe production migrations.
  • DevOps: Docker, GitLab CI/CD, Nginx, Linux; monitoring and logging with Prometheus, Grafana, ELK / Sentry.
  • Testing: JUnit, Mockito, PyTest and integration tests with Testcontainers — 65% of services covered.
  • Mentoring and onboarding of juniors, technical interviews; introduced AI agents (Claude Code / Codex) into the team.

03 — Skills

Tech stack

Languages

JavaKotlinPythonSQLJavaScriptBash

Frameworks & Libraries

Spring BootSpring SecuritySpring Data JPAHibernateSpring CloudDjangoDRFCeleryasyncio

Databases

PostgreSQLMySQLMongoDBRedisElasticsearchLiquibase / Flyway

Messaging & APIs

Apache KafkaRabbitMQREST APIsOpenAPISOAPOAuth2 / JWTKeycloak

DevOps & CI/CD

DockerDocker ComposeGitLab CIGitNginxLinuxAnsibleTerraform

Monitoring & Logging

PrometheusGrafanaELKSentry

Testing

JUnitMockitoPyTestTestcontainersPostman

Build & Tools

GradleMavenPIPJiraConfluenceIntelliJ IDEA

Experience matrix

Years of hands-on experience and the year each was last used.

04 — Experience

Where I've worked