Senior Android Engineer - High-Throughput Payments

Startupplay; Dublin; Hybrid; EUR 100,000 - 140,000; Full time

Benefits offered by this job

Hybrid work model

Benefits package

Job summary

Toast is seeking a Senior Software Engineer for Card Readers to ensure fast, reliable payment processing across large-scale Android codebases. You will design, develop and maintain high-performance JVM-based services, mentor teammates, and collaborate across backend, product, UX/UI, and QA to deliver secure, scalable payment experiences.

The role emphasizes strong API design, observability, and ongoing adoption of emerging technologies, with a hybrid work model across regions.

Qualifications

• Expert-level proficiency in Kotlin, Java and JVM languages.
• Deep knowledge of multi-threading/concurrency; coroutines a plus.
• Experience in large Android projects with modular architecture.
• Track record of robust SDK integrations.
• Experience designing public APIs for easy consumption.
• Observability, monitoring and alerting for complex interactions.
• Mentoring fellow developers on best practices.
• Openness to AI tooling to boost R&D productivity.
• Excellent communication and collaboration skills.

Responsibilities

• Design, develop and roll out high-performance Kotlin applications.
• Lead technical discussions on best practices, performance, and security.
• Collaborate with backend, product, UX/UI, QA to deliver seamless payment experiences.
• Optimize mobile payment flows for security, speed, and reliability.
• Balance maintainability with delivering value to customers iteratively.
• Ensure PCI-DSS and security standards compliance.
• Mentor engineers, conduct code reviews and promote best practices.
• Troubleshoot complex issues ensuring high availability.
• Participate in agile processes and stay current with tech trends.

Skills

Kotlin/Java/JVM

Multithreading

Android project experience

Public API design

Observability/Monitoring

Mentoring

AI tooling awareness

Communication & collaboration

Security/compliance (PCI-DSS)

Distributed systems/microservices

Tools

SDK integrations

Public API design

Job description

Toast is seeking a Senior Software Engineer for Card Readers to ensure fast, reliable payment processing across large-scale Android codebases. You will design, develop and maintain high-performance JVM-based services, mentor teammates, and collaborate across backend, product, UX/UI, and QA to deliver secure, scalable payment experiences.

The role emphasizes strong API design, observability, and ongoing adoption of emerging technologies, with a hybrid work model across regions.