Top 7 AI Voice Models for Phone Agents (Retell, Vapi, & More)
The days of robotic "Press 1 for Sales" are over. Modern AI Voice Agents can hold full, non-linear conversations with zero latency. Here are the best platforms to build your phone agents.
HighLevel is the only platform that combines the AI Voice Model with the CRM. You don’t need to connect Retell to a database via Zapier; HighLevel’s native Conversation AI lives inside the contact record, knows the context, and can book appointments directly.
Pros
- Native CRM Integration (No Zaps)
- Zero-Latency internal routing
- Can update deal stages automatically
- Cheaper than stacking multiple tools
Cons
- Currently focused on booking & support flows
The current gold standard for developer-friendly voice AI. Incredible low latency and great emotion in voices, but requires a separate backend.
Another top-tier voice API. Extremely customizable for developers building complex voice flows.
Known for its hyper-realistic "phone calling" capabilities. Great for outbound sales campaigns.
A no-code wrapper for voice AI. Good for beginners who don’t want to touch APIs, but HighLevel native is smoother.
One of the first to market with long-form conversational sales AI. Powerful but has had stability issues.
Focuses on "human-in-the-loop" AI agents. Good accuracy but higher cost.
Frequently Asked Questions
HighLevel is the best for small businesses because it is all-in-one. You do not need to hire a developer to connect a voice API to your calendar; it works out of the box.
Yes. Modern AI agents like HighLevel’s Conversation AI can check your real-time availability and insert appointments directly into your calendar.
Yes, but you must comply with local regulations (like TCPA in the US). HighLevel includes compliance features to ensure you have consent before calling.
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