Founding Engineer

About the job

HARMONICA

We are a London based stealth startup (ex Revolut, Meta, Imperial PhD) building the defining AI company for ageing. Ageing is one of society's biggest problems, and for us it's personal. We're an expat team building for our own ageing parents, who live far away in China, India, Brazil, and Italy.

We build voice first technology to keep seniors at home, healthier and happier for longer.

Our first product is Olympia, a proactive voice assistants for older adults living at home. She provides conversation and stimulation, remembers what matters, connects the family, and notices changes in wellbeing. Real seniors already use her in real homes. She's voice-first, proactive, and gets more useful the longer she knows someone.

Hear what it means to live with Olympia from one of our user: ay0pj21d8yt6k6y

OUR AMBITION

By 2050, the number of people over 80 will triple, and care systems are already running out of money, workers, and capacity. Today's system sees the cliff: the fall, the hospital admission, the crisis. Olympia sees the drift, and acts while the problem is still small.

We're here to win the category. The opportunity is massive: this is where tech meets good, at the scale of how the world ages. Daily use of Olympia builds a picture of how people age that nobody has had before: cognition, mood, routines, mobility, social connection. Across millions of homes, that intelligence lets families act earlier, helps clinicians support far more people, and saves billions in care spending. Harmonica becomes the infrastructure an ageing world runs on.

Five-year goal: 250,000 homes, $170M revenue. You'd be one of the first engineers building the product that gets us there.

WHO WE ARE

Team from Meta, Revolut, Tractable, and an Imperial PhD in voice AI. We've built consumer products at scale, taken AI products from pilots to eight-figure contracts, and worked at the frontier of real-time speech.

Backed by Eileen Burbidge's NFG Ventures, Mati Staniszewski of ElevenLabs, and many more, with research collaborators at Oxford, Wharton, and Toronto.

WHAT WE'LL DO TOGETHER

• An AI-native engineering org. Agents across coding, reviewing, QA, ops, support, scheduling. You'll help turn the company itself into an intelligent system.
• Speech-to-speech agents that feel like a person in the room. Interruptions, back-channels, noisy kitchens, hearing aids, thick accents, millisecond latency.
• Companions with long-term memory. Knows someone after six months the way a friend would.
• Assistants inside messaging, connecting families across cities and countries.
• Health biomarkers from conversation. Cognitive decline, mood, breathing, loneliness, with research partners at Wharton, Toronto, and Oxford.
• PhD-level audio in production. Speech enhancement, VAD, diarization, TTS tuned for older voices.
• An agentic browser: booking appointments and getting things done online through conversation, no wrestling with websites.

WHAT WE'RE LOOKING FOR

• A cracked, AI-native engineer. You use AI to multiply what you ship, and you've made yourself measurably faster with coding agents or your own setup.
• You've shipped something that runs on an LLM in production. Voice AI experience (real-time STT, TTS, speech-to-speech, telephony) is a plus but not needed.
• You go above and beyond and can prove it: a side project, a repo people star, a hackathon you won, something you built over a weekend because you couldn't stop. Show us.
• High agency. If something is broken and nobody owns it, you own it now. You'd rather be wrong fast than wait for a spec.
• Product taste. You care how it looks and feels, not just whether it works.
• Low ego, kind, hard-working. No politics.
• You care about the mission: older adults ageing well at home, work that matters to real families.

WHAT WE DON'T CARE ABOUT

• Where you went to university, or whether you did. Show us what you've built.
• Where you live. Overlap with London hours matters more than your postcode.
• Gender, age, background, or anything else that isn't the work.

FOUNDING ENGINEER MEANS FOUNDING

You will be integral to whether Harmonica succeeds. That's literal, and it comes with the freedom to match.

• Set the engineering standards: how we test, review, deploy, and use agents as we grow.
• Shape the stack. A strong opinion backed by evidence changes how we build.
• Hire the team. You'll interview and help decide who joins after you.
• Own broadly today (voice, memory, messaging, biomarkers); take primary ownership of a major surface as we grow.
• Real equity and a real voice in product, engineering, and company decisions.
• You'll learn more here in one year than in three elsewhere. That's a promise.

THE PACKAGE

• 0.5% to 1.5% equity, depending on seniority, on a standard four-year vest.
• What that could be worth. If we hit the plan ($170M revenue in year five), a business like ours trades at roughly 5x to 10x revenue, putting Harmonica between $850M and $1.7B. After typical dilution from future rounds, your stake would be worth in the region of $2.5M to $20M+. This is a projection, not a guarantee; startups fail, and we're telling you what we're aiming at.
• Competitive salary.
• Hardware, tooling, and model spend. Nobody waits for approval to try a new model.
• Maximum creative freedom, and a team building this for our own parents.