Senior Backend Engineer, Payments

ABOUT HAULER HERO Hauler Hero is a modern, multi-tenant SaaS platform built for the waste management industry. We help haulers run smarter operations, from dispatch and routing to driver workflows, billing, and customer payments. Hauling companies across North America run on Hauler Hero every day. Our customers bill and collect payments through the platform, so reliability and accuracy matter in everything we build. ROLE SUMMARY We are hiring a Senior Backend Engineer to join our payments team. You will share ownership of the platform that moves our customers' money, including card processing, refunds, reconciliation, and the processor integrations behind them. This is a 100% hands-on senior IC role. You will design and ship the systems that make payments safe by construction, while refactoring and extending what exists as the platform scales. The role requires strong technical judgment, comfort with ambiguity, and clear communication in a remote environment. AI-FIRST BACKEND ENGINEERING We are intentionally building an AI-assisted engineering organization. AI tools are part of the daily workflow, not optional. What this means in practice: • Daily use of tools such as Claude, Claude Code, Cursor, and GitHub Copilot • AI-assisted implementation of Spring Boot services, APIs, database migrations, and business logic • AI-assisted test generation, refactoring suggestions, and code review support • AI-assisted log analysis, debugging, and issue investigation You remain accountable for reviewing, validating, and owning everything AI produces. In payments, that bar is higher than anywhere else in the codebase. Speed matters, but a subtle bug moves real money, so correctness matters more. This role is not a fit for engineers who are resistant to AI-assisted development or who rely on AI output without understanding the underlying system. KEY RESPONSIBILITIES PAYMENTS PLATFORM • Design, build, and operate the services behind card processing, refunds, and payment reconciliation • Own our processor integrations behind a common connector layer, including onboarding new processors and retiring old ones • Make the payment pipeline safe by construction through idempotent charge paths, processor timeouts and retries outside database transactions, webhook handling, and an automated reconciler that catches stuck or mismatched payments • Build audit trails so every payment and refund is traceable • Be a first responder for payments incidents and drive root cause analysis and structural fixes, not one-off scripts • Partner with Customer Success on the payments support queue and turn recurring tickets into product fixes CORE BACKEND DEVELOPMENT • Write clean, testable, high-performance code in Kotlin and Java using Spring Boot; new backend code is written in Kotlin • Design and implement APIs that scale with real production workloads • Refactor and extend existing services to improve reliability and maintainability DATA & PERFORMANCE • Design and optimize relational schemas in PostgreSQL • Write and tune performant SQL for large data volumes and validate that access patterns scale under load COLLABORATION & DELIVERY • Work as part of a cross-functional Agile/Scrum team and participate in design reviews, code reviews, and architectural discussions • Collaborate with product, frontend, and Customer Success on billing and payments features • Mentor engineers through code reviews and proactively share context to avoid knowledge silos REQUIRED QUALIFICATIONS EXPERIENCE • 5+ years building production backend systems • 2+ years building or operating payment systems in production, including card processing, recurring billing, refunds and reversals, or reconciliation • Direct experience integrating with at least one payment processor or gateway API • Experience designing and operating systems with distributed data and meaningful scale • Experience working in Agile/Scrum environments, with strong Git/GitHub workflow experience CORE TECHNOLOGIES • Strong proficiency with Spring Boot (Java and/or Kotlin) and willingness to write Kotlin as your primary language • Deep experience with relational databases, especially PostgreSQL • Experience building and maintaining production APIs PAYMENTS • Working knowledge of idempotency, at-least-once vs. exactly-once processing, retries, and reconciliation patterns for money movement • Understanding of PCI DSS scope and tokenization; you know what must never touch our servers • Experience with financial edge cases, including partial refunds, voids vs. reversals, chargebacks, declined and stuck transactions, and timezone-sensitive scheduling SKILLS • Ability to translate product requirements into technical solutions • Strong problem-decomposition and debugging skills, including production incident work • Solid computer science fundamentals and engineering judgment • Clear written and verbal communication skills NICE TO HAVE • Integrations with payment processors • Ledger design or double-entry accounting concepts; invoicing and accounts-receivable systems • ACH or bank-payment experience • Event-driven architectures such as Pub/Sub or Kafka • Google Cloud Platform, including GKE, Cloud Run, and Cloud SQL, and Redis • Background in fintech, B2B SaaS, or logistics • Frontend experience with React OUR TECH STACK • Backend: Kotlin, Java, Spring Boot, PostgreSQL • Payments: Multiple card processors behind an in-house connector layer; Redis for idempotency and reconciliation • Cloud: Google Cloud Platform (GKE, Cloud Run, Cloud SQL) • Caching: Redis, Firestore • Frontend: React • CI/CD: Cloud Build, GitHub Actions • Monitoring: New Relic, Google Operations WHAT WE LOOK FOR OWNERSHIP & JUDGMENT • You take problems through to resolution • You balance pragmatism with quality, and in payments you know quality wins • You identify and eliminate single points of failure, both in systems and in knowledge COMMUNICATION • Clear, proactive written communication • Willingness to surface risks and tradeoffs early • Calm and precise during incidents; you document what happened and what changes MINDSET • Curious, growth-oriented, and adaptable • Comfortable with ambiguity and iteration • Willing to refactor continuously as systems evolve COMPENSATION & BENEFITS • Competitive salary + equity • Health, dental, vision insurance • Flexible PTO • Remote-first culture • Modern development tools and AI assistants