Compare / Hail vs Vapi
Hail vs Vapi
Vapi and Hail both host the voice call loop. Vapi is a platform for building voice agents. On Hail, a call is one agent tool next to SMS and email.
Updated Aug 20265 min readBy the Hail team
Vapi and Hail both host the voice call loop. Vapi is a platform for building voice agents. On Hail, a call is one agent tool next to SMS and email.
Choose Vapi if voice is your product and you want assistant configuration, vendor choice, and detailed tuning of the call. Choose Hail if your agent runs in Claude, LangGraph, or your own code and also sends SMS and email.
Vapi orchestrates STT, LLM, and TTS vendors and runs the realtime call loop. It has assistant configuration, testing tools, and integrations. You can set up a voice agent without writing the agent code.
To send a confirmation text or a follow-up email in the same workflow, you add other vendors. Each vendor has its own account and bill. Vapi charges a per-minute platform fee in addition to the STT, LLM, TTS, and telephony charges. Vapi is closed source. You cannot self-host it.
If a larger agent controls the workflow, Vapi covers one channel of it. You also maintain the Vapi assistant configuration.
For SMS and email, you add other vendors to Vapi.
Your agent passes a system prompt over MCP or REST. Hail's hosted voice pipeline runs the conversation, with turn detection and a transcript. Hail stores the result in the same event ledger as the SMS and email that the agent sends. You do not select STT or TTS vendors.
You pay per use at published per-minute and per-message rates, from one balance. There is no platform subscription. Hail is open source (AGPL), so you can read the code and self-host it.
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This page reflects Vapi's published capabilities and pricing as of August 2026. They change. Verify current details on Vapi's site.
One key, one invoice, pay-as-you-go. See pricing.