Senior Software Engineer - Android

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

Senior Software Engineer - Card Readers Toast is building the all-in-one restaurant platform that helps restaurants operate their business, increase sales, engage guests, and keep employees happy. Toast connects employees, operations, and guests on a reliable, easy-to-use platform so restaurateurs can stay one step ahead of a rapidly evolving hospitality market. The Card Readers team processes millions of card payments a day for Toast’s restaurant customers. Hundreds of thousands of restaurants depend on the software we build to run their business. We make payments friction-free while maintaining the highest levels of security, enabling new payment options, and staying at the forefront of emerging technologies. As a Senior Software Engineer on the Card Readers team, it’s your job to make sure those millions of payments are processed quickly, reliably, and securely. You will be a key team member responsible for designing, developing, and maintaining our POS payment integrations. You will work closely with hardware SDKs, the core POS application team, and other cross-functional stakeholders to drive technical decisions and refine the target architecture for our payment solutions. Your expertise in high-throughput asynchronous JVM solutions, coupled with a deep understanding of mission-critical transaction processing, will be crucial in delivering robust and scalable solutions.

Responsibilities

• Design, develop and roll out robust, high-performance applications using Kotlin.
• Lead technical discussions and decisions on best practices, performance optimizations, and security.
• Collaborate with cross-functional teams (backend, product, UX/UI, QA) to deliver seamless payment experiences.
• Optimize mobile payment flows for security, speed, and reliability.
• Shape the face of development at Toast by helping to balance building maintainable software for long term success, with the need to deliver value to customers in an iterative fashion.
• Ensure compliance with PCI-DSS, security best practices, and other financial industry standards.
• Mentor and guide junior engineers, conduct code reviews, and drive best practices in software development.
• Troubleshoot and resolve complex technical issues, ensuring high availability and performance.
• Participate in agile development processes, including sprint planning, daily stand-ups, and retrospectives.
• Stay up to date with emerging technologies, frameworks, and trends.

Requirements

• Expert-level proficiency in Kotlin, Java, and/or JVM languages.
• Deep knowledge of multi-threading/concurrency (experience with coroutines a plus).
• Experience working in a large (Android) project/codebase, architecting for clear domain boundaries, modularity, reusability, and testability.
• Track record of complex and robust SDK integrations completed successfully.
• Experience designing public APIs for hassle-free consumption.
• Expertise in observability, monitoring, and alerting for complex user-device interactions.
• Strong skills in mentoring fellow developers on best practices.
• Openness and enthusiasm for AI tooling to enhance R&D productivity.
• Excellent communication, collaboration, and problem-solving skills that lead others by example.
• Nice to have: Card Payments/EMV experience.
• Nice to have: Hardware/device integration experience.
• Nice to have: Security and key management experience.

Special Sauce

• Prior experience with distributed systems and microservices.
• Experience with EMV Payments or Kernel.

AI at Toast

At Toast, one of our company values is that we’re hungry to build and learn. We believe learning new AI tools empowers us to build for our customers faster, more independently, and with higher quality. We provide these tools across all disciplines, from Engineering and Product to Sales and Support, and are inspired by how our Toasters are already driving real value with them. The people who thrive here are those who embrace changes that let us build more for our customers; it’s a core part of our culture.

Our Total Rewards Philosophy

We strive to provide competitive compensation and benefits programs that help to attract, retain, and motivate the best and brightest people in our industry. Our total rewards package goes beyond great earnings potential and provides the means to a healthy lifestyle with the flexibility to meet Toasters' changing needs. Learn more about our benefits at https://careers.toasttab.com/toast-benefits.

Our Approach to Hybrid Working

We embrace a hybrid work model that fosters in-person collaboration while valuing individual needs. Our goal is to build a strong culture of connection as we work together to empower the hospitality community, regardless of location. Please visit the Locations page on our career site to learn more about our in-office expectations by region: https://careers.toasttab.com/locations-toast

People Are the Secret Ingredient in Our Recipe for Success

At Toast, our employees are our secret ingredient - when they thrive, we thrive. The restaurant industry brings together people with a wide range of backgrounds, experiences, and perspectives, and we value that same breadth at Toast. We strive to build a culture grounded in authenticity, respect, and humility, where every Toaster has a real opportunity to grow, contribute, and do their best work - raising the bar in delivering exceptional experiences for our customers and each other.

Accessibility and Inclusion

Toast is committed to creating an accessible and inclusive hiring process. As part of this commitment, we strive to provide reasonable accommodations for persons with disabilities to enable them to access the hiring process. If you need an accommodation to access the job application or interview process, please contact [e-mail].

Legal Disclaimer

For roles in the United States, it is unlawful in Massachusetts to require or administer a lie detector test as a condition of employment or continued employment. An employer who violates this law shall be subject to criminal penalties and civil liability.