AI agent developers, voice AI firms and agent frameworks, sorted by what you're automating.

It depends on scope. An agent built on an existing platform or framework with a few integrations costs far less than a custom multi-agent system with retrieval, tool use and production monitoring. Most firms start with a paid discovery phase, then quote a fixed or monthly price for the build. Our lists note what each company focuses on so you can compare like with like.

A chatbot answers questions in a conversation. An AI agent can also take actions: it plans steps, calls tools and APIs, reads and updates data, and completes tasks with less human input. Many products sit somewhere between the two, so check what a vendor’s agent can actually do on its own.

A ready-made AI receptionist or answering service gets you live quickly for standard call handling. A developer makes more sense when calls need to connect to your CRM, booking or contact-center systems, follow custom logic, or work across several languages. Our voice AI lists cover both routes.

Each list is researched by ReVerb’s editors against the criteria set out in that list, covering services, client work, reviews and public footprint. Lists are refreshed as the market changes.