Software Engineer

about us

At telli we are building AI voice agents that are reshaping an entire industry.

Since launching 8-months ago, we raised a $3.6M pre-seed round from Cherry and Y Combinator and grew to >$1M in ARR. We are looking for a team members who want to go all-in to help us achieve the next milestone: $10M in ARR.

Two of our co-founders Finn and Philipp previously scaled the heat pump unit of energy unicorn Enpal from 0-150 people. They've seen the ins and outs of scaling phone-based customer processes. These businesses are rushing to deploy AI voice agents. However, creating a demo is easy — building reliable agents that handle millions of calls in production is incredibly hard.

In a world where intelligence becomes a commodity, it is up to us builders to craft new product experiences that let people harness the power of AI.

But building AI voice agents comes with challenges:

• What is the most intuitive way for humans to build and adjust their own AI agents?

• How do you build agents that work reliably across millions of calls in a world of non-determinism?

• How do you ensure that customers can use the latest foundational models without having to understand the technical trade-offs?

• How do you enable companies to build hybrid teams of human and AI agents?

• What does human-computer interaction look like if, instead of having UI elements, you have a hyper-intelligent sidekick?

These are unsolved problems. Problems that haven't existed since the invention of computers. Solutions that worked in a pre-LLM world won't work today. Nobody knows how to solve these problems; it's up to us to figure it out.

We’re a small, fully in-person team based in Berlin. Even though most people have told us to build this company in SF because of “better talent” - we know there is amazing talent in Europe. We believe you can build a multi-billion dollar software company in Europe, and there is no better time to do this than now.

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.

Right now our engineering team consists of Paulus , Philipp , Błażej , and Seb . We are planning to bring on 2 more people (one of them could be be 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 , Modal and Pipecat . 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 what it takes to succeed in a fast-paced, high-ambiguity environment and ideally worked in an early stage startup

• 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

• great pay & equity

• access to any (AI) tool that makes you more productive

• gym subscription

• a bright and beautiful office in Berlin Mitte

• company trip to San Francisco in fall 2025