About the company
Our partner is looking for a Backend Engineer – API Integrationen, Connectoren, Worker/Jobs, Mailer Service, QA based in Netherlands. This role is an opportunity to build robust backend systems and integrations that connect critical business platforms and services.
Responsibilities
- Build and maintain production-ready API integrations and connectors, prioritizing Box and HubSpot, followed by Microsoft Graph, Asana, and billing-related systems.
- Implement reliable authentication and integration patterns using OAuth, webhooks, pagination, rate limits, retries, and robust error handling.
- Design and develop queue-driven, stateful, and replayable workers and background jobs.
- Build and maintain a mailer service supporting PDF attachments, structured logging, retry mechanisms, delivery checks, and deduplication/idempotency.
- Design database schemas and implement clean, reliable migrations using PostgreSQL or comparable technologies.
- Implement audit events and persistent traceability mechanisms, including correlation IDs and observability across distributed processes.
- Develop comprehensive QA coverage, including contract tests, integration tests, and end-to-end regression testing for critical workflows such as document delivery and deadline-related processes.
- Use Docker, queue/eventing technologies, and observability practices to support reliable deployment and operation of backend services.
- Proactively identify failure modes and strengthen systems against timeouts, webhook failures, rate limiting, retries, duplicate events, and other production scenarios.
Requirements
- Strong professional track record in backend engineering, with proficiency in Python, Node.js, Go, or a comparable backend technology.
- Proven experience building and maintaining production API integrations, including OAuth, webhooks, pagination, rate limits, authentication, and error handling.
- Solid understanding of relational databases, schema design, data persistence, and safe database migrations.
- Strong testing mindset with experience implementing contract, integration, unit, and/or end-to-end tests.
- Experience developing asynchronous, queue-based, or event-driven systems and background workers.
- Understanding of reliability engineering principles, including idempotency, retries, replayability, deduplication, observability, and failure-mode analysis.
- Experience working with Docker and modern backend development and deployment workflows.
- Familiarity with PostgreSQL, queue/eventing systems, and application monitoring or observability tools.
- Strong problem-solving skills and the ability to design systems that remain reliable outside of ideal or “happy path” scenarios.
- Ability to work independently, take ownership of technical deliverables, and communicate clearly in a remote project environment.
- Availability to work remotely, ideally aligned with Central European Time (CET) or European working hours.
- Freelance or project-based experience is suitable for this engagement.
Conditions
- 100% remote working arrangement.
- Flexible project-based engagement with workload agreed upon according to availability and project needs.
- Full-time or part-time engagement options.
- Freelance contract structure.
- Opportunity to work on technically challenging API integrations, worker systems, messaging infrastructure, and QA automation.
- Significant ownership over backend architecture, implementation, reliability, and delivery.
- Opportunity to start as soon as possible.
- Collaboration within an international and digitally focused professional environment.