Kotlin/Java Developer, Merchant Response

Mayflower

Kotlin/Java Developer developing solutions for a payment gateway facilitating transactions for merchants and users. Collaborating on a high-load system architecture ensuring PCI DSS compliance.

Posted 6/17/2026full-timeRemote • 🇺🇸 United StatesMid-LevelSeniorWebsite

Tech Stack

Tools & technologies

ApacheAWSKafkaKotlinMySQLNoSQLRedisSpring

About the role

Key responsibilities & impact

Developing new payment features and services;
Processing and resolving requests from technical support and users as part of daily duties;
Designing and implementing APIs (external and internal);
Creating and maintaining processes in Camunda;
Participating in the design and development of high-load system architectures;
Supporting and enhancing existing solutions and services;
Writing high-quality, test-covered code (unit tests, integration tests);
Conducting code reviews;
Optimizing system performance and database queries;
Analyzing and resolving production incidents and bugs;
Analyzing documentation from external providers, conducting quick checks, and defining epics and tasks based on Proof of Concept;
Collaborating with the QA team to ensure the high quality of the delivered product;
Maintaining technical documentation and writing technical specifications;
Assisting in onboarding new developers and ensuring code quality;
Definition and formation of technical epics — analyzing existing solutions, identifying opportunities to improve system architecture, performance, and reliability, preparing improvement proposals, and aligning them with the team lead and architect;
Participation in the creation of business epics — analyzing requirements, assessing feasibility, and proposing alternative or optimized solutions based on technical expertise; collaborating with analysts and product managers to determine the best implementation approach;
Preparing tasks based on approved epics, ensuring proper detailing and alignment with architectural and business requirements;
Estimating task completion timelines, participating in sprint planning, and providing accurate technical time and effort estimates.

Requirements

What you’ll need

3+ years of commercial development experience with Kotlin;
Experience with the Spring Framework;
Experience in developing payment solutions (billing, payment gateways, payment processors, exchanges);
Practical experience integrating with external providers;
Experience designing and optimizing relational databases (MySQL);
Experience with NoSQL databases (Redis);
Practical experience using AI-assisted coding tools (Claude, Codex, ChatGPT, Codeium, etc.) to improve speed and quality of development;
Ability to critically review AI-generated code, ensuring production-ready quality and compliance with company standards;
Knowledge of Event-Driven Architecture principles and experience working with distributed messaging systems (e.g., Apache Kafka);
Excellent command of core software development and design principles, test-driven development (TDD), and CI/CD processes;
Strong understanding of microservice architecture.
Preferred Qualifications:
Experience with Camunda (creating and supporting processes);
Solid understanding of PCI DSS standards, ISO 27001, and other information security methodologies;
Practical experience working with AWS;
Experience with Jira and GitLab CI/CD.

Benefits

Comp & perks

Full remote work.
Competitive compensation with a service contract.
Transparent performance reviews twice a year, with bonus opportunities and salary adjustments.
An annual allowance that you can use for home office improvements, sports activities, equipment upgrades, and more—tailor it to what benefits you most.
Investment in your development: paid language courses, access to various learning platforms, and a mindfulness benefit, including psychological support with 50% coverage.
Career growth in a fast-scaling project with opportunities to influence technical decisions.
A culture of recognition: our peer reward program celebrates contributions from across the team.

ATS Keywords

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Applicant Tracking System Keywords

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Hard Skills & Tools

KotlinSpring Frameworkpayment solutionsMySQLNoSQLAI-assisted coding toolsEvent-Driven Architecturemicroservice architecturetest-driven developmentCI/CD

Soft Skills

code reviewscollaborationcritical reviewproblem-solvingcommunicationonboardingestimating timelinesparticipation in sprint planning

Certifications

PCI DSSISO 27001