Senior Backend Engineer, Payments

Hauler Hero Inc.•New York, NY

4d•Remote

About The Position

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.

Requirements

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
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
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
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 Haves

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

Responsibilities

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
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
Design and optimize relational schemas in PostgreSQL
Write and tune performant SQL for large data volumes and validate that access patterns scale under load
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