# Sierra Review

> Sierra review: Outcome-priced conversational AI agent platform from Bret Taylor and Clay Bavor; voice product replaces IVR with an empathetic agent. Verified.

Outcome-priced conversational AI agent platform from Bret Taylor and Clay Bavor; voice product replaces IVR with an empathetic agent.

Among the 31 voice ai tools we track, Sierra has the 9th-widest language coverage - a fit for multilingual and localization projects.

See pricing · facts verified Jul 30, 2026

## What we know about Sierra

This is our verified profile of Sierra, a voice ai platform - outcome-priced conversational AI agent platform from Bret Taylor and Clay Bavor; voice product replaces IVR with an empathetic agent. Every fact about Sierra below carries the source it came from and the day we checked it.

Sierra does not publish a public per-minute rate we have been able to verify, so the price figure here stays blank until we can confirm one. We would rather show nothing than a guessed number; if you have a current Sierra quote, it is the fastest way for us to close that gap.

On capabilities, Sierra covers warm transfer to human, dtmf / ivr navigation, interruption handling (barge-in), soc 2 type ii, gdpr tooling / eu residency, and simulation/testing suite for agents, and does not offer self-serve signup. Each of those is verified against Sierra's own docs or dashboard, not marketing copy.

For compliance, with Sierra: HIPAA is included on the plans we checked and SOC 2 Type II is in place. If you are in a regulated space, confirm the current posture with Sierra before you commit, since these change plan by plan.

Sierra ranks the 9th-widest language coverage of the 31 voice ai tools we track, so where it lands for you depends on which of those matters more.

In total we track 12 verified facts for Sierra today, each linking the primary source it came from so you can check our work - and vendor claims we have not measured ourselves are labeled as such on the Sierra fact sheet below.

## Fact sheet

### Capabilities

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Warm transfer to human | ✓  Yes | Jul 30 | [source](https://sierra.ai/product/voice) |
| Languages supported | 55 count | Jul 30 | [source](https://sierra.ai/product/voice) |
| DTMF / IVR navigation | ✓  Yes | Jul 30 | [source](https://sierra.ai/product/voice) |
| Interruption handling (barge-in) | ✓  Yes | Jul 30 | [source](https://sierra.ai/product/voice) |

### Compliance & trust

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| HIPAA BAA on base plan | ✓  Included | Jul 30 | [source](https://sierra.ai) |
| SOC 2 Type II | ✓  Yes | Jul 30 | [source](https://sierra.ai) |
| GDPR tooling / EU residency | ✓  Yes | Jul 30 | [source](https://sierra.ai) |

### Build experience

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Simulation/testing suite for agents | ✓  Yes | Jul 30 | [source](https://sierra.ai) |

### Commercial

| Fact | Value | Verified | Source |
| --- | --- | --- | --- |
| Self-serve signup | ✗  No | Jul 30 | [source](https://sierra.ai) |
| Support tier / SLA on base plans | Outcome-based pricing; pay per resolution | Jul 30 | [source](https://sierra.ai) |
| Founded year + HQ | 2023, San Francisco | Jul 30 | [source](https://www.cnbc.com/2025/09/04/bret-taylor-sierra-ai-startup-salesforce-openai.html) |
| Funding stage (credibility signal) | $350M round at $10B valuation (Sep 2025, led by Greenoaks) | Jul 30 | [source](https://www.cnbc.com/2025/09/04/bret-taylor-sierra-ai-startup-salesforce-openai.html) |

## Sierra head-to-head

| Comparison | Record | Per use case |
| --- | --- | --- |
| [Sierra vs Decagon](https://www.versusref.com/voice-ai/decagon-vs-sierra/) | won 2 · lost 3 · tied 1 | No-code agency deploys: lost; Custom pipeline control: won; Ecommerce support and orders: won; Healthcare compliance: tie; Outbound sales campaigns: lost; SMB receptionist and booking: lost |

Source: https://www.versusref.com/voice-ai/tools/sierra/