How telli Turned AI Voice into Operational Impact

Note: The following contributions are personal impulses from Max Eckel. They represent individual reflections and are intended to stimulate discussion and further thought.

telli’s new $15M round is a useful case for why the last mile of AI is operational, not technical. At Enpal, an unanswered phone call did not just mean an unanswered phone call. It meant a service appointment that did not happen.

WHU alum Finn zur Mühlen (BSc 2020) and Philipp Baumanns had helped scale Enpal’s heat-pump business to more than 150 people in its first year. They saw what happens when a consumer company adds customers faster than its service operation can absorb them: call queues, missed appointments, endless callbacks, and skilled people spending their day on repetitive coordination.

Together with Seb Hapte-Selassie, they built telli around that experience. An AI agent that speaks fluently is impressive in a demo. But fluency was not the business case for Enpal. The agent had to connect to its routing system, call when customers were actually available, handle return calls and rescheduling, make several follow-up attempts, and leave the complex cases to humans.

The results are much more interesting than how human the voice sounds: Enpal says its connection rate increased from 75% to 90%. Weekly appointments rose by 30%. The service dispatch organization saved 40% of its time while reaching 20% more customers. That is business impact.

The commercial founder’s job is not to stand next to great technology and explain it. It is to decide which operational number the technology must move... and then redesign enough of the workflow to make that happen. That requires customer understanding, integrations, exception handling, measurement, and constant improvement. The unglamorous work between “the model can do this” and “the customer is better off because it does.”

Maybe that is why telli is now positioning itself beyond AI voice agents: as AI for customer-facing operations. Voice is the interface. The value sits in the system behind it. The company’s agents now handle millions of conversations for businesses including Enpal, Sky, Viessmann, and Vaillant. The $15M seed round led by redalpine, with participation from Mutschler, Cherry Ventures, Y Combinator and several angel investors, brings total funding to $18.5M.

Congratulations to Finn, Philipp, Seb, and the entire telli team.

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