About us At telli, we're building the first AI-native phone system. Since launching last year at Y Combinator, we've grown to 50 customers and >$2M in ARR with a team of only 12 people. Today, most B2C companies fail in their customer communication not because they don't care, but because they can't keep up. The sheer volume of calls forces them to outsource to poor-quality external call centers or have their internal teams spend hours on repetitive, easy calls. With telli, our customers now rely on AI voice agents that handle their repetitive calls, freeing human agents to focus on what matters - talking to customers when it counts. The result: higher efficiency, happier teams, and better customer experiences. We've seen firsthand that legacy phone systems are not designed for an AI-first world. That is why we are building the first AI-native phone system that lets B2C companies manage both their human and AI teams on one platform. Our founding team knows this problem inside-out, having managed a 150-person call center before. We know how painful and expensive scaling phone operations can be for companies. There is a lot of work ahead. The opportunity is massive. We are ending an era of poor-quality external call centers. about the role This is a high-ownership, high-impact role for engineers who care about velocity and solving real customer problems. You won't just ship code; you will own projects end-to-end, make core product and architectural decisions, and shape the future of this company. We believe in building a small A* engineering team. We plan to keep the core engineering team small, even while we scale and rely on engineers who have super high impact on the growth of the company. That is why to succeed, you need to be comfortable with working on any part of our stack. One week you might be polishing the UX of our frontend, the next week dive deep into async processing challenges of our voice AI infrastructure. If you only want to work on a specific technology/part of the product, this might not be the right role for you. what you will do work closely with our customers, understand their problems, and come up with product experiences that solve their challenges build scalable backend infrastructure to handle thousands of AI phone calls a day build intuitive user experiences that make sense in an AI-first world own high stakes projects end-to-end tech stack Our tech stack includes TypeScript, React, TanStack, Node, Python, Postgres as well as Temporal.io, Twilio, and Modal. But more than familiarity with any specific technology, we value a how fast you can learn and the ability to ship end-to-end features. what makes you a great fit you align with our principles you love challenging work and consistently go above and beyond you take full ownership of projects you want to work in-person in Berlin you know how to prioritize high-leverage work you want to work with a smart and driven team with (self-reported) low ego you want to help build a multi-billion dollar company from the ground up you may not make a good fit if… you prefer a remote-first environment you like to work on your own with minimum collaboration you have no prior experience in software engineering teams you only want to work with specific technologies instead of the entire development stack you think AI is just "hype" and doesn’t provide real value you want to work 9-5 perks above-market pay & equity access to any (AI) tool that makes you more productive urban sports subscription