Software Engineer

Boldr is a hardware-enabled climate tech startup rethinking how people use energy at home.

Our mission is simple but ambitious: “help every household cut energy consumption by up to 30%, without giving up comfort.”

We do this by combining beautifully designed smart hardware with powerful, intuitive software that gives people real control and insight into their home energy use.

Born between the US, Europe and Brazil, we’re building for a global challenge: the next generation of smart thermostats and energy devices that are affordable, interoperable, and ready for the future grid. We’ve recently raised US $5.2M in a seed-extension round, backed by leading climate and deep-tech investors, and are now expanding our product and engineering teams.

At Boldr, you’ll join a small, world-class team of engineers and product thinkers who care deeply about craft, sustainability, and impact. We move fast, stay curious, and build things that make the world a bit bolder and a lot more efficient.

The Role

As a Senior Software Engineer, you’ll build the software that connects thousands of thermostats in real homes to the people who rely on them: homeowners, HVAC contractors, and eventually the grid.

You’ll work closely with Boldr’s CTO/CPO, product, design and our firmware team. Your code will control real heating and cooling equipment, so reliability isn’t optional.

You’ll:

• Design and build our cloud platform: the APIs, data pipelines and services behind our apps and Boldr Care.
• Own the link between device and cloud: messaging, provisioning, telemetry ingestion and safe firmware update rollouts.
• Ship features in our mobile apps for homeowners and contractors, from install flows to monitoring and alerts.
• Turn raw device data into products: Health Scores, alerts, and insights that help people save energy.
• Make systems observable and resilient as our installed base grows, and take part in incident response when something breaks in the field.
• Raise the bar for the team through code reviews, technical design, and mentoring.

We’re an early-stage startup, which means you’ll have real ownership and the freedom to shape both our product and culture from day one.

About You

You might have built backend systems at a scale-up, shipped connected devices, or been an early engineer at a startup.

What matters is that you’ve owned systems end to end, shipped them to real users, and kept them running when things got messy.

We’re looking for:

• Fluent English (our customers, partners and team are global)
• 5+ years of software engineering experience, with strong backend and system design skills
• Hands-on experience with cloud infrastructure (AWS preferred) and event-driven or distributed systems
• Comfort working across the stack, from APIs and databases to mobile apps
• Bonus: IoT experience (MQTT, device provisioning, OTA), Flutter, or time-series data
• Bonus: interest in embedded systems and working alongside firmware engineers
• Curiosity, self-direction, and a startup mindset, no task too big or small

Education doesn’t matter that much to us. What you’ve built and how you think do.

Why Boldr

At Boldr, we’re building technology that actually matters: tools that help people reduce their footprint and energy bills at the same time. If you want to combine engineering, sustainability, and hardware to make a tangible impact, this is the place.

The role is hybrid: mostly remote, with occasional in-person collaboration at our São Paulo office 🇧🇷.