Vapi alternative for managed voice agents
Build with Atoms when you want Smallest to handle speech and telephony around your application logic. If you only need a new voice, you can also use Smallest as a voice provider inside Vapi.
Do you need to leave Vapi to use Smallest?
No. Vapi lists Smallest AI as a supported voice provider, so you can change the speech layer without moving your agent platform. Choose Smallest Atoms as a Vapi alternative when you also want Smallest to run speech, calling, and agent operations around your application logic. Keep Vapi when independent provider selection is central to your architecture.
Smallest Atoms vs Vapi: platform and provider choices
Compare a full Atoms deployment with Vapi’s configurable provider architecture. Changing the voice provider is a smaller project than moving agent orchestration, tools, and telephony.
| Smallest AI | Vapi | |
|---|---|---|
| Architecture | Managed speech and telephony around crew logic | Configurable STT, LLM, and TTS providers |
| Use them together | Available as a Vapi voice provider | Lists Smallest AI as a voice option |
| Application logic | Own the LLM turn in Agent Crews | Configurable assistants and model providers |
| Tools and workflows | Agent tools and custom crew code | Custom tools, integrations, and squads |
| Phone calls | Phone agent operations | Inbound and outbound calling |
| Web integration | Agent WebSocket sessions | Voice assistants for applications |
Operate your calling workflow with Smallest Atoms
Bring speech and telephony around your code
Agent Crews lets your code own the reasoning and tools while Smallest manages the voice infrastructure around it, so the logic specific to your product stays in your application.
Give your team a place to operate calls
Atoms includes campaigns, transcript review, and configuration history, so you can move beyond a speech request to the day-to-day work of running agents.
Start with a voice-only change
Vapi lists Smallest AI among its voice providers. Use that path when your assistant’s workflow already works and the change you need is in speech generation.
Use Smallest Atoms for lead qualification calls
An agent can ask your qualification questions and pass structured details to the business logic you connect. Use Atoms when you want that workflow and calling around your code, or keep Vapi and change the voice when its orchestration already fits.
1
Gather the caller’s needs using your qualification instructions.
2
Pass the required fields to your connected CRM logic.
3
Complete the next action or route the caller through the configured handoff.
Smallest voice agent pricing for Vapi users
A voice-only change and a platform migration have different bills. If you keep Vapi, include its platform and other provider costs in the estimate. If you move to Atoms, build the estimate around the Smallest architecture you choose.
Platform hosting
Smallest lists $0.01 per minute for pay-as-you-go hosting. This is one component of a call, not the total call price.
Speech, reasoning and calling
A cascading agent adds STT, LLM, TTS and telephony. A speech-to-speech agent adds its speech-to-speech model and telephony.
Your operating requirements
Check CRM writes, transfers, and structured outputs with a limited group of calls, and confirm how operators recover failed calls before moving more traffic.
Should you choose Smallest or Vapi?
Choose Smallest AI when
Bring more of the conversation to Smallest
Choose Atoms when you want Smallest to operate speech and telephony around your application logic. For a voice-only change, use Smallest through Vapi’s supported provider integration.
Choose
Vapi
When
When Vapi may be the better fit
Keep Vapi when swapping individual transcription, LLM, and voice providers is central to your architecture. Smallest can still be part of that setup through Vapi’s voice provider integration.
Frequently asked questions
Can I use Smallest without leaving Vapi?
When should I choose Atoms instead of changing the voice provider?
Can I keep my application logic in code?
Does moving from Vapi preserve my tool integrations automatically?
How should I compare platform costs?
Is Smallest a Vapi alternative for outbound voice AI?