Senior Java Software Engineer

Mangopay

. Participate in day-to-day development by making architectural decisions, designing robust systems, and conducting design and code reviews .

Posted 10/9/2026full-timeWarsaw • PolandSeniorWebsite

Core Competencies

Role fit

Core Competencies

Use this summary to align your resume positioning with the role.

Demonstrates expertise in Backend Development with a focus on Java, Micronaut, and cloud-native architectures. Proven ability to design and implement scalable, event-driven systems while collaborating effectively with cross-functional teams.

Highest-signal resume keywords

Java Development (Java 11-21+)Cloud Native Frameworks (Micronaut, Spring Cloud)Event-Driven Architecture (Kafka, RabbitMQ)High-Throughput, Low-Latency SystemsUnit and Functional Testing (JUnit 5, Spock)

ATS Keywords

Tailor your resume

Applicant Tracking System Keywords

Tip: use these terms in your resume and cover letter to boost ATS matches.

Hard Skills

Backend DevelopmentJava DevelopmentMicronaut FrameworkSpring CloudEvent-Driven SystemsKafkaRabbitMQUnit TestingFunctional TestingCloud Architecture

Soft Skills

CollaborationMentoringLearning MindsetProblem-SolvingCommunication

Tools & Technologies

AWSAI-Assisted Development ToolsClaude CodeCursorCodexLLMs

Industry Keywords

FintechBankingPaymentsHigh-Throughput SystemsLow-Latency Products

Tech Stack

Tools & technologies

AWSCloudJavaJUnitKafkaRabbitMQSpring

About the role

Key responsibilities & impact

Participate in day-to-day development by making architectural decisions, designing robust systems, and conducting design and code reviews
Ensure consistent implementation against architectural principles and define new standards to future-proof the ecosystem
Collaborate with software engineers, principal engineers, architects, and product managers to break down complex problems into deliverable value
Ensure best practices for system monitoring, alerting, and proactive failure detection
Partner with the Engineering Manager on strategic technical and organizational improvements
Learn Mangopay APIs and identify architectural or performance improvements
Gain autonomy in the event-driven architecture and own a major technical epic from design through production
Partner with Product and QA on acceptance criteria and zero-downtime deployments
Lead architecture decisions, designs, design reviews, code reviews, and implementation
Potentially participate in hiring and mentor future software engineers
Lead new projects from product requirements through technical implementation and production delivery
Maintain, improve, and add features to systems handling massive concurrent traffic and transaction spikes
Build and integrate fintech features and payment flows without compromising reliability or backward compatibility

Requirements

What you’ll need

7+ years as a Backend developer using Java (Java 11 through Java 21+)
Experience building high-throughput, low-latency products, ideally within the fintech, banking, or payments industry
Experience developing software using Micronaut or another cloud native framework (Spring Cloud) in large-scale production systems
Comfortable working in a modern cloud architecture using AWS or another cloud environment
Deep experience designing, building, and troubleshooting highly scalable, event-driven systems using Kafka, RabbitMQ, or similar distributed messaging frameworks
Ability to create unit and functional tests with JUnit 5 or Spock
Learning- and growth-focused mindset with a strong desire to share skills and learn from others
Experience leveraging AI-assisted development tools (e.g., Claude Code, Cursor, Codex, LLMs) is highly valued