By Abdullah Sufyan · Voxovo AI
Compare Voxovo AI, Vapi, and Retell on key features like BYO numbers, live call tools, agency support, and dead‑air handling. Find the best platform for production voice AI.
Choosing the right AI calling platform can feel like navigating a maze of features and pricing. This post offers a side‑by‑side look at Voxovo AI, Vapi, and Retell, the three most prominent players in production voice AI today. We focus on core capabilities that matter to businesses—BYO telephony, live call tools, agency tenancy, and dead‑air handling—so you can make a data‑driven decision.
When evaluating an AI calling stack, start with four pillars: carrier control, real‑time interaction tools, scalability for teams, and latency safeguards. A carrier‑agnostic design lets you use Twilio, Telnyx, Plivo, or Vonage without vendor lock‑in. Real‑time tools such as CRM lookups, calendar booking, and custom HTTP calls keep agents productive mid‑call. Finally, low turn latency and a presence buffer prevent callers from hearing silence.
Voxovo AI is a production‑ready voice platform that plugs into any of the four leading carriers. It supplies the complete speech stack—STT, TTS, voice models, and a built‑in LLM—and lets you bring your own numbers. The dashboard authenticates via Google OAuth or a Voxovo email, and APIs are secured with JWTs or custom keys. All this is wrapped in a single console where you can manage agents, campaigns, and data integrations.
Three features set Voxovo AI apart. First, the Presence Buffer pre‑caches filler audio so the caller never hears dead‑air while the LLM processes a request. Second, Live Sheet and Live Calendar let agents pull in spreadsheets or book slots on the fly, eliminating back‑and‑forth clicks. Third, the Voxovo 1.0 native modes—Speed, Smart, Ultra—offer a spectrum of turn latency and accuracy, plus a fully customizable ‘Custom’ mode for total control.
Voxovo’s launch offers 10 free AI credits for seven days with no card needed. After the trial, you email info@voxovo‑ai.com with the desired plan (Growth, Usage, Agency) and workspace name. We then confirm payment and grant the credits manually. Because the platform is still in early launch, there is no self‑serve checkout on the site—customers receive a personalized onboarding experience.
Vapi positions itself as a developer‑first API hub for voice assistants. It emphasizes a lightweight JSON‑based schema and offers a suite of pre‑built voice assistants that can be customized with prompts. Vapi supports both inbound and outbound calls via any SIP or PSTN provider, but it requires you to manage carrier accounts and number provisioning yourself.
Vapi’s strengths lie in flexibility for software engineers. The platform exposes low‑level voice primitives—transcription, synthesis, and context handling—through REST endpoints that can be chained in any workflow. Developers can also plug in their own LLM or TTS engine, giving them a fully open architecture. However, Vapi does not provide built‑in live‑call tools like CRM lookups or calendar booking; those must be built in the application layer.
Vapi charges based on usage metrics such as API calls and minutes. Since the platform is open‑source in many respects, there are no upfront costs for the core API, but carriers and third‑party services still bill separately. The cost structure is transparent but can grow with the number of custom integrations you add.
Retell focuses on ultra‑low‑latency telephony for high‑volume, real‑time interactions. The company offers a managed voice channel that integrates seamlessly with any LLM or speech engine you choose. Retell’s architecture is optimized for minimal buffering and fast packet routing, making it suitable for live customer support and IVR systems.
Retell’s key differentiator is its telephony backbone, which provides turn latency under 200 ms for most regions. It also offers a “Live” mode where you can stream raw audio to external services without intermediate buffering. Retell does not bundle a knowledge base or deep integrations; it expects you to wire your own data sources and tooling.
Like Vapi, Retell’s pricing is usage‑based and tied to carrier costs. There are no hidden fees, but the platform charges per minute of voice usage and per data packet processed. Customers must also provision their own number pools or work with a carrier partner.
Below is a quick feature comparison for the four pillars we identified:
Agency tenancy: Voxovo AI provides an omni‑sk portal for agencies to manage multiple workspaces, while Vapi and Retell rely on separate accounts for each client. This makes Voxovo more attractive for partner firms that need to isolate data per customer. Vapi and Retell lack a built‑in agency dashboard, but developers can build custom admin layers.
Mid‑call tools: Voxovo bundles 20 deep integrations out of the box—HubSpot, Salesforce, Google Calendar, and more—enabling agents to search knowledge bases, book meetings, and pull ticket details live. Vapi offers a flexible HTTP webhook system, but you must create your own integration logic. Retell provides minimal tooling; you must connect your own CRM or calendar API.
Dead‑air handling: Voxovo’s Presence Buffer guarantees zero silent intervals, whereas Vapi and Retell rely on the LLM or downstream service to manage pauses. This can noticeably improve caller satisfaction in scenarios where the LLM needs time to compute responses. If your use case requires strict call continuity, Voxovo’s buffer is a decisive advantage.
When choosing a platform, run a bake‑off that measures turn latency, API call throughput, and ease of integration. Test with your own telephony provider, your preferred LLM, and the real‑world data sources you will use. The first three minutes of the call are often the most critical, so include latency scoring in your test criteria.
Geographic and compliance concerns vary by carrier. Voxovo’s BYO model allows you to keep numbers in the regions where you operate, which can help satisfy data residency requirements. Vapi and Retell also support global carriers, but you must manage number allocation yourself. All three platforms encrypt call audio end‑to‑end when using their native TTS/LLM pipelines.
We also added a quick knowledge‑base search capability on the Speed and Smart modes: mid‑call agents can issue a `search_knowledge` request to pull relevant documents and display them in the agent UI—something Vapi and Retell do not provide out of the box.
Ready to test the differences for yourself? Sign up for a 10‑credit free trial at https://voxovo‑ai.com or email info@voxovo‑ai.com to discuss a custom plan. The Voxovo team will guide you through a quick demo and help you set up a live bake‑off with your chosen carriers and data sources. Let’s build the next generation of AI‑powered calls together.
Questions about Voxovo AI? Email info@voxovo-ai.com
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