Finn zur Muehlen, Philipp Baumanns and Seb Hapte-Selassie said on July 23rd that their Berlin-based startup, telli, had raised a $15 million seed round to expand its AI agents from phone calls into the broader machinery of customer service, sales and support.
redalpine led the financing. Existing backers Cherry Ventures and Y Combinator participated alongside Mutschler Ventures and angels including Marc Bitzer, Alexa von Bismarck, Martin Koehler and Krischan von Moeller. The transaction brought telli's stated total funding to $18.5 million, a figure also reported by redalpine's legal adviser, Osborne Clarke.
That total appears rounded. The seed follows a $3.6 million pre-seed announced on April 15th, 2025, which would put the simple sum of the two reported rounds at $18.6 million.
From Enpal's call center to AI customer operations
Zur Muehlen and Baumanns found the problem while building the heat-pump operation at German energy business Enpal. The founders said they expanded that unit to more than 150 people during its first year, while calls, lead qualification, appointment booking and customer support remained difficult to automate.
Baumanns was the second employee in Enpal's heat-pump unit, according to YC. Hapte-Selassie studied computer science at Stanford and previously built software at Pitch. The three founders started telli in 2024 and took part in YC's Fall 2024 batch.
That background shaped telli's initial product: voice agents for high-volume consumer businesses that depend on phone outreach to convert leads or complete operational tasks. In its YC launch materials, telli focused on industries selling complex products, including energy, insurance and real estate, where missed calls can stall a purchase or service appointment.
The new financing backs a wider pitch. telli now offers agents across voice, chat, SMS, WhatsApp and email. Those agents can answer calls, qualify leads, schedule appointments, run follow-ups, transfer conversations and resolve customer requests while connecting to the systems used by human sales and service workers.
At the center of the product is Charlie, which telli describes as an AI coworker for customer-facing staff. Charlie helps users configure agents, connect internal systems, review conversations, detect problems and test changes to prompts and workflows. The shift makes telli a customer-operations platform rather than a single-purpose voice agent vendor.
Enterprise customers provide the proof point
telli says its agents have handled millions of conversations for customers including Sky, Enpal, Vaillant and Viessmann. Those conversation counts and performance figures are self-reported, and telli has not published revenue or annual recurring revenue with the round.
The named deployments still give redalpine a clearer enterprise adoption case than a seed-stage voice demo. In a telli case study, Enpal said the product increased weekly service appointments by 30%, saved 40% of its dispatch operation's time and helped it reach 20% more customers. Enpal used the agents for appointment confirmations, inbound rescheduling and repeated follow-up calls.
Bark, a marketplace connecting customers with service professionals, reported adding 800 hours of weekly calling capacity, increasing connection rates by 25% and cutting cost per contact by 70% after deploying telli for provider outreach and job clarification. Those figures also come from a case study produced by telli.
Sky said it deployed its initial use case in two to three weeks and enabled employees to write their own prompts, according to telli's account of the rollout. That ability to put agent configuration in the hands of operations staff is central to telli's attempt to sell beyond engineering teams.
An application-layer bet
Zur Muehlen told Tech Funding News that telli does not intend to become an AI research lab. "We just want to give the best solution to the customer possible," he said, adding that the underlying model is secondary to the outcome.
That approach puts the founders in a crowded market. Legacy contact-center vendors such as Genesys, Five9, Talkdesk and Aircall are adding AI to existing communications products. AI-native vendors including Vapi, Retell, Synthflow, Parloa and Bland are also competing to build or operate voice agents.
telli is betting its advantage comes from owning the operational workflow surrounding each conversation: agent setup, integrations, analytics, quality review and continuous improvement. The founders' Enpal experience gives that argument weight. They built the human operation before trying to automate its repetitive work.
The seed capital will fund hiring across engineering, go-to-market and customer operations as telli expands internationally. YC currently lists telli with 16 employees in Berlin. The next test is whether the founders can turn the early enterprise deployments into repeatable sales across the energy, insurance, telecom, healthcare and real-estate sectors they are targeting.