McGen Digital
Turned an untraceable cost center into a live billing platform running real money.
THE SITUATION
McGen had already sold multiple clients on AI voice agents — a strong offer on its own. But every agent ran through McGen's own accounts across ElevenLabs, Vapi, and Twilio. With several clients sharing the same underlying accounts, there was no reliable way to see which client was driving which cost. Billing became guesswork: either McGen absorbed costs it couldn't trace, or under-billed clients who were using the service heavily. Both quietly erode margin the moment you scale past a handful of clients.
WHAT I BUILT
Usage tracking engine
Tracks consumption per client in real time across ElevenLabs, Vapi, and Twilio, tying every cost back to the exact account driving it.
Next.js · Supabase · provider APIs
Automated billing pipeline
Handles the full billing cycle — invoicing, failed card retries, negative balance handling, and line items like rented phone numbers.
Stripe · Supabase · Resend
Client dashboard
Full frontend and backend so McGen and their clients can see usage and charges without anyone pulling reports manually.
Next.js · Supabase Auth
WHAT CHANGED
What used to be an unbillable black box is now a live production system serving 14 active users and processing over $8,000 in client billing. McGen can keep adding voice AI clients without the backend cost problem scaling right alongside them.