Senior Backend Developer (freelance)

In short

If you're a backend engineer who doesn't just build what's asked, but shapes how it's built, we want to talk. We're looking for someone who can own the technical direction of a project end to end: architecture, infrastructure, trade-offs, and the conversations that come with them. You'd join us on a freelance, time & material basis: you're paid for the hours you actually work on real client projects. Full capacity from the start. The first three months are about figuring out if we're a good match. When things work out, and that depends on the work itself, the project pipeline, and business timing, there's a real path to our core team with a permanent contract and full benefits.

Why intent?

We've been designing and co-creating connected devices since 2008. Wearables, smart audio, health-tech hardware for clients like Oura and BOSE, backed by investors like a16z and Founders Fund. We're 60+ people, fully remote, and AI-native since before LinkedIn influencers discovered the term. We use AI every day, in actual work, not just in company decks. Our backend isn't generic CRUD: it's the cloud spine of physical devices, the layer where firmware meets data pipelines, and where one bad architectural call shows up in a sensor reading six months later.

Who this role is NOT for

If your comfort zone is a well-defined Jira board, clear specs, and someone else making the architectural calls, this isn't going to work. We're not hiring a senior developer who executes well. We're hiring someone who decides what gets built, how it gets built, and why. Someone who walks into a room full of ambiguity and starts creating structure, not waiting for it. If you need a ticket to start moving, if "that's not in the requirements" is a sentence you use often, or if you'd rather not be the one explaining a technical trade-off to a client, we're probably not your people. We're AI-native and we expect you to treat AI tools as a daily multiplier, not a gimmick.

What you'll do

• 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

How we work

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 clients (up to ~20:00) are part of the rhythm, sometimes a couple of times a week, always planned ahead. You'll be part of the Mobile chapter (which covers backend/cloud too) for knowledge-sharing, and at the same time on a project squad led by a PM for day-to-day delivery.

What you'll get

• 90-180 PLN/h net B2B, depending on your experience

• Truly flexible hours: you organize your day

• Fully remote, with pet-friendly Warsaw office + Gdansk cowork if you want them

• Access to our internal knowledge-sharing: tech talks, experiments, side projects

• When the first 3 months work out, and that depends on the work, the project pipeline, and business timing, there's a real path to a permanent contract with a fixed monthly salary, 26 days paid leave, 10 sick days, Saltus medical care, and a training budget

No sugarcoating: during the freelance period there's no paid leave or medical benefits. Those come with the permanent contract, and we're transparent about that upfront.

Your first weeks

We aim to give you space to ramp up before jumping into live project work, but thi