Senior QA Engineer (freelance)

In short If you're a Senior QA Engineer who's tested apps that talk to physical devices, and you know that "reproduce on my phone" doesn't end the conversation, we want to talk. You'd join us on a freelance, time & material basis : you're paid for the hours you actually work on real client projects. 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 Cobalt Streamworks ? 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. Our QA isn't "check the screens": it's a mobile app talking to firmware over BLE, sometimes with a flaky signal, sometimes at the edge of battery, sometimes on a phone that decided to update overnight. The bugs are real, the details matter, and good QA changes whether a product ships well or limps out the door. Who this role is NOT for If you like running the same test pass every sprint and closing tickets the moment the build is green, we're probably not your people. We look for QA who ask "why" before "how", challenge specs that don't add up, and dig into firmware logs when something smells off. We're AI-native and we expect you to treat AI as a daily multiplier, not a gimmick. What we expect: ownership of what you touch, straight talk when something is wrong, and the kind of curiosity that makes you actually care about the device, not just the app on top of it. What you'll do Compatibility testing: make sure devices, sensors, gateways, protocols, and platforms actually play well together Functional testing: data collection, storage, processing, real-time monitoring, control, integrations Performance testing: behavior under different workloads, networks, and physical conditions, finding bottlenecks and latency Security testing: vulnerabilities in devices, communication protocols, transmission, storage, access, auth Mentor less experienced testers, raise the bar on QA practices Take part in requirement discussions and daily calls, flag inconsistencies and open issues early Share knowledge inside the QA chapter and across the company Use AI tools as part of your daily workflow, not as a party trick 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 QA chapter 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 90-130 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 this is a real company with real deadlines: if the project needs you sooner, we'll make sure you have the support to hit the ground running. You'll get paired with a buddy and tackle progressively bigger tasks, so both sides can see how the collaboration feels. Feedback comes early and often, no one waits three months to tell you something isn't working. If it's great, you'll know. If something needs adjusting, you'll hear about it while there's still time to adjust. Recruitment process The entire process is in English. All interviews are recorded for internal evaluation purposes. Application with a few screening questions HR call, ~45 min, casual Technical meeting, ~90 min, with the QA team Final feedback within a few days Once we're in touch, you'll hear from us fast. We don't ghost and we don't drag. One more thing Cobalt Streamworks is an equal opportunity employer. We care about what you can do, not where you come from. Send us your CV and a few words about why this caught your eye. Bonus points if you share a bug you found that nobody else would have. Requirements What we're looking for 4+ years of professional mobile QA experience Prove