Senior Backend Developer (freelance)

Responsibilities

• Own and evolve the backend architecture for IoT projects: data ingestion pipelines, API design, infrastructure decisions
• Make technical trade-off calls and defend them clearly to the team and to clients
• Design and maintain cloud infrastructure on AWS (EKS, Aurora, DynamoDB, Timestream, S3) with production-grade reliability
• Lead technical discussions: RFCs, architecture reviews, post-mortems, because you see the need, not because someone asked
• Mentor other backend engineers, raise the bar on code quality, and set patterns others can follow
• Work side by side with firmware engineers, mobile developers, QA, PMs, and clients
• Use AI tools as part of your daily workflow, not as a party trick
• Challenge product and technical assumptions when something doesn't add up, even when it means a harder conversation
• Fully remote. We have a pet-friendly office in Warsaw and a coworking space in Gdansk if walls and coffee machines motivate you, but nobody will ask why you're not there. Working hours are flexible: most of the team operates between 10:00 and 18:00 CET, and that's when most meetings happen. Evening calls with US-based…

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