Senior Software Engineer - Fullstack (SaaS product/Payroll)

About EarnIn As one of the first pioneers of earned wage access, our passion at EarnIn is building products that deliver real-time financial flexibility for those with the unique needs of living paycheck to paycheck. Our community members access their earnings as they earn them, with options to spend, save, and grow their money without mandatory fees, interest rates, or credit checks. We’re fortunate to have an incredibly experienced leadership team, combined with world-class funding partners like A16Z, Matrix Partners, DST, Ribbit Capital, and a very healthy core business with a tremendous runway. We’re growing fast and are excited to continue bringing world-class talent onboard to help shape the next chapter of our growth journey. POSITION SUMMARY We are looking for a passionate and resourceful Senior Software Engineer to join the EarnIn payroll services team. In this role, you will participate in the design, development, and implementation of frontend and backend services that support the full suite of EarnIn Payroll’s products including our integration platform and payroll SaaS product. Your work will ensure backend systems and user-facing applications are well-aligned, intuitive, and reliable for payroll customers. Come make a difference with us and have fun doing it! This position is hybrid from our Bangkok office as part of our expanding site. EarnIn offers excellent benefits, including healthcare, internet and cell phone reimbursement, a learning and development stipend, and potential opportunities to travel to our Mountain View, CA headquarters. Our salary ranges are determined by role, level, and location. WHAT YOU'LL DO Contribute to the design and development of backend components such as payroll and tax processing engines, ledger services, and pay cycle management. Build and maintain services and APIs using Go (Golang), C#, or other modern languages, focusing on maintainability, security, and performance. Partner closely with frontend engineers to design APIs and data models that enable intuitive, performant, and scalable user experiences. Contribute to frontend development for the payroll SaaS product, helping build and maintain user-facing features that are reliable, accessible, and easy to use. Design, implement, and maintain services to integrate with partner platforms and expedite the customer onboarding process for EarnIn Payroll’s new SaaS product. Collaborate with product managers, designers, and other engineers to deliver features that meet the needs of payroll customers. Assist in investigating and troubleshooting production issues, learning to apply root cause analysis and propose improvements. Support the development of scalable and reliable microservices for time-critical financial workflows. Participate in code reviews, learning and applying best practices while improving your own coding skills. Help ensure features are delivered with quality and within agreed timelines. WHAT WE'RE LOOKING FOR 4+ years of professional software development experience (internships or projects may count). Bachelor’s degree in computer science, engineering, or a related technical field, or equivalent practical experience. Experience building or contributing to modern frontend applications (e.g., React, Vue, TypeScript, or similar frameworks) and a strong appreciation for user experience and usability preferred . Experience using AI-assisted development tools (e.g., Copilot, Cursor, LLMs) is a plus. Proficiency in at least one modern programming language (e.g., Go, Python, C#, or similar). Experience working with relational databases. Familiarity with cloud platforms (AWS preferred). Exposure to infrastructure-as-code tools (e.g., Helm, Kustomize, Terraform) is a plus. Interest in working with Kubernetes-based environments and learning to optimize for resiliency and scalability. Comfort collaborating across the stack, including working closely with design and product to translate requirements into user-facing functionalit