Kotlin/Java Developer (Integration)

Stack

Responsibilities

• ▹Develop new payment integrations and services
• ▹Automate and optimize integration processes
• ▹Analyze external provider documentation, run quick checks, and define epics/tasks based on Proof of Concept
• ▹Participate in designing and developing high-load system architectures
• ▹Support and improve existing solutions and services
• ▹Write high-quality, test-covered code (unit and integration tests)
• ▹Conduct code reviews
• ▹Optimize system performance and database queries
• ▹Analyze and resolve production incidents and bugs
• ▹Process support and user requests as part of daily duties
• ▹Collaborate with the QA team to ensure high product quality
• ▹Use AI tools to accelerate delivery of integration modules and build internal tools to generate integration code from business requirements
• ▹Maintain technical documentation and write specifications
• ▹Help onboard new developers and ensure code quality
• ▹Define technical epics: analyze existing solutions, identify architecture/performance/reliability improvements, align proposals with the team lead and architect
• ▹Participate in creating business epics: analyze requirements, assess feasibility, propose alternative or optimized solutions
• ▹Prepare tasks from approved epics, participate in sprint planning, provide accurate time and effort estimates

Requirements

• ▹3+ years of commercial development experience with Kotlin (Java a plus)
• ▹Experience with the Spring Framework
• ▹Experience developing and integrating payment solutions (billing, payment gateways, processors)
• ▹Practical experience integrating with external payment providers
• ▹Experience designing and optimizing relational databases (MySQL)
• ▹Experience with NoSQL databases (Redis)
• ▹Practical experience with AI-assisted coding tools (Copilot, ChatGPT, Codeium, etc.)
• ▹Ability to critically review AI-generated code for production-ready quality and compliance
• ▹Knowledge of Event-Driven Architecture principles, experience with distributed messaging systems (e.g. Apache Kafka)
• ▹Excellent understanding of software development and design principles, TDD, and CI/CD
• ▹Solid understanding of microservice architecture
• ▹English proficiency level B1 or higher

Nice to have

• ▹Experience with Camunda (creating and supporting processes)
• ▹Solid understanding of PCI DSS, ISO 27001, and other information security methodologies
• ▹Practical experience with AWS
• ▹Experience with Jira and GitLab CI/CD

Soft skills

About the company

Mayflower's team is developing a payment gateway for accepting funds from users on behalf of merchants and sending funds from merchants to users. The system stores user payment data and is subject to PCI DSS compliance, with multiple integrations with payment systems, providers, and processors, including 3DS.