Real pricing, real deployment timelines, and the hidden costs nobody puts on their homepage. Vapi vs Retell vs Synthflow vs GoHighLevel vs Wave Runner.
I picked the wrong voice AI platform in early 2024. It cost me roughly $20,000 and six months before I fully understood why.
I was building voice AI agents for agency clients. Picked a platform because it had the most flexibility, the best demo, and the pricing page said "$0.05 per minute." Sounded great.
Three months in, I realized the $0.05 was just the platform fee. The actual cost per minute, once you stacked speech recognition, the LLM, voice synthesis, and telephony, was closer to $0.28. My margins were gutted. And I hadn't even gotten to the real problem yet.
The real problem: the knowledge base worked maybe 10% of the time. My client's agent was supposed to answer questions about their services, pricing, and availability. Instead, it made up answers. Confidently. To real prospects on real phone calls.
I switched platforms. Tested another one. Better knowledge base, but the interface was built for developers. My ops team couldn't configure a new client without filing a support ticket. Then I tried a third. No-code builder, which was great, until I noticed the platform's branding leaking through in client-facing emails. Hard to charge premium rates when your "proprietary AI receptionist" has someone else's logo on the error page.
After 18 months, I'd tested five platforms in production with real clients paying real money. I documented everything because I kept wishing someone had done this before I started.
This is that document.
One thing before we get into it. I now run a voice AI platform (Wave Runner). I'll be transparent about that throughout this report. When I get to Wave Runner's section, I'll show the same data points I show for every other platform and let you evaluate it the same way. I'll also include the honest limitations, because every platform has them, including mine.
If you're an agency deciding which voice AI platform to build on, this will save you the tuition I paid. The pricing numbers are from actual invoices. The timelines are from real onboarding experiences. The complaints are things I ran into with live client traffic, not hypothetical scenarios.
Most comparison articles line up feature lists. That's useless for agencies. Features don't ship voice AI to a client. These five criteria do.
1. True Per-Minute Cost
Not the advertised rate. The actual number on your invoice when speech recognition, the LLM, voice synthesis, and the platform fee are all included. Every platform structures this differently. Some bundle it. Some break it into five separate charges. The number that matters is the total.
2. White-Label Quality
Can your client use the dashboard without seeing the platform's name? What about error pages, call recordings, and login screens? "White-label" means different things to different platforms.