Senior Backend Engineer (Contractor)

Hauler Hero Inc.

Polska

Hybrid

PLN 470,000 - 705,000

Full time

14 days+

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Job summary

Hauler Hero Inc. seeks a Senior Backend Engineer (Contractor) to design, build, and evolve core backend services powering their platform. This hands-on role focuses on scalable, reliable, and maintainable systems used by North American waste haulers.

The ideal candidate has 5+ years in production backends, strong Java/Kotlin with Spring Boot, and experience with distributed data and SQL optimization. Remote role with overlap to U.S. hours.

Qualifications

5+ years of production backend experience.
Experience with distributed data and large-scale systems.
Agile or Scrum experience.
Strong Java/Kotlin with Spring Boot background.

Responsibilities

Design, build, and maintain backend services.
Write high-performance, testable code in Java/Kotlin.
Design scalable REST/API interfaces.
Refactor services for reliability and maintainability.
Collaborate with Frontend, Product, and Platform teams.
Participate in design and code reviews.

Skills

Backend design

Distributed systems

Java

Kotlin

Spring Boot

PostgreSQL

SQL tuning

API design

Code reviews

English communication

Education

Computer science fundamentals

Tools

GitHub workflows

SQL tooling

CI/CD (Cloud Build, GitHub Actions)

Job description

Senior Backend Engineer (Contractor)

Location: Remote - Eastern Europe or LATAM
Engagement: Contractor
Experience: Senior, 5+ years
Time zone: Must consistently overlap with U.S. working hours

About Hauler Hero

Hauler Hero builds the operating system for residential and commercial waste haulers, including dispatch, routing, billing, payments, customer management, reporting, and the driver app that ties field operations together.

Our customers are private hauler owners, operators, and municipal waste leaders running essential services every day. Many are still managing their businesses through paper tickets, whiteboards, spreadsheets, disconnected systems, and legacy software. The result is missed revenue, messy routes, limited visibility, and too much time spent fighting fires instead of growing the business.

Today, we serve 240+ haulers across the country and are scaling quickly. We are a well-funded, fast-moving vertical SaaS company bringing modern software to an essential industry where the customer need is clear and the opportunity is large.

Role Summary

We are hiring a Senior Backend Engineer to design, build, and evolve the core backend services that power Hauler Hero's platform.

This is a 100% hands-on senior individual contributor role focused on building scalable, reliable, and maintainable systems used daily by waste hauling companies across North America.

You will work closely with Product, Frontend, and Platform Engineering to ship features, improve system robustness, and continuously refactor existing services as the platform scales. This 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

Speed matters, but correctness, performance, and maintainability matter 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

Core Backend Development

Design, build, and maintain robust backend service layers
Write clean, testable, high-performance code in Java and/or Kotlin using Spring Boot
Design and implement APIs that scale with real production workloads
Refactor and extend existing services to improve reliability and maintainability
Create reusable components and patterns that improve team velocity

Data and Performance

Design and optimize relational schemas in PostgreSQL
Write and tune performant SQL queries for large data volumes
Validate that database access patterns scale under load
Identify and resolve performance bottlenecks across services

Collaboration and Delivery

Work as part of a cross-functional Agile or Scrum team
Participate in design reviews, code reviews, and architectural discussions
Collaborate with Frontend and Product teams on feature development
Debug and resolve production issues as they arise
Contribute to improving engineering processes and practices

Mentorship and Culture

Mentor engineers through code reviews and technical discussions
Contribute to a culture of learning, iteration, and constructive feedback
Share context proactively to avoid knowledge silos

Required Qualifications

Experience

5+ years of experience building production backend systems
Experience designing and operating systems with distributed data and meaningful scale
Experience working in Agile or Scrum environments
Strong experience with Git and GitHub workflows

Core Technologies