Why we built our own AI phone agent instead of renting one
Renting an AI answering service is the fastest way to stop missing calls, and for most small businesses it’s the right start. We built our own, Ace, because we needed control: our own prices and lookups, changes the same day, and no per-minute markup. If the phone is central to your business and you need the agent to work inside your own systems, owning it starts to pay off.
Our roadside business gets calls at every hour. For a while an outside vendor ran our AI phone agent. It worked, but it became one of the biggest frustrations in the business. This is what we learned building our own.
What renting felt like
- Every change went through someone else. New services, new wording, a fix for a confusing question: all of it waited on the vendor.
- The logic lived in their accounts. The agent’s behavior was spread across the vendor’s automation tools, so we couldn’t see or test it ourselves.
- We paid a markup on every minute. On top of the underlying AI and phone costs.
What we built instead
Ace runs on our own stack. A call to one of our numbers goes to Twilio ConversationRelay, which turns speech into text and back and handles interruptions. Each call gets its own small server on Cloudflare that streams the conversation to Claude. When Ace needs to do something, it calls our own Phoenix API: verify the ZIP code, quote from our price list, look up a job, save the lead.
Ace also handles our speed to lead: when someone completes a request form on our website, Phoenix calls them about 30 seconds later and Ace confirms the details. Read the full case study.
What owning it gave us
- Same-day changes. New behavior is a code change, tested and deployed by us.
- Real integration. Ace books straight into dispatch and looks up live jobs, instead of emailing someone a message.
- Guardrails we control. It reads back services before booking, never invents one, texts a location link when a caller is unsure, and hands off to a person when it should.
When renting is the right call
If you mainly need someone to answer, take a message and book into a common calendar, renting is simpler and cheaper to start. That’s exactly the gap Call Rey, our AI receptionist product, is built for. Build your own when the phone is the core of the business and the agent needs to work inside your own systems.
Questions to ask any AI answering service
- Can I change what it says myself, today?
- Does it book into my real calendar or system, or just send a message?
- What exactly do I pay per minute, and is there a markup?
- What happens to my phone number if I cancel?
- Can it transfer to a person, and when does it?