Retell AIAI Voice Agents That Automate Phone Calls
vs
SierraHelps businesses build better, more human customer experiences with AI.
Comparison · AI Agents · weekly run Nov 3
Retell AI vs Sierra
Which one do AI engines recommend, and how do they differ on price, fit and features?
The short answer
Retell AI is the stronger AI pick in AI Agents: it has a visibility score of 2 versus 1.5 for Sierra.
Choose Retell AI if…
- You want the brand AI engines rank higher (2 vs 1.5)
- You need a self-hosted or on-premises option
- You need HIPAA or SOC 2 Type II or GDPR or ISO 27001 coverage
- Highly rated by developers and SMBs
Choose Sierra if…
- You prefer a larger, established vendor (1,001–5,000 employees)
AI visibility side by side
Latest weekly run · Nov 3
| Metric | Retell AI | Sierra |
|---|---|---|
| Visibility score | 2% | 1.5% |
| Change vs last week | New | New |
| Rank in AI Agents | #42 | #49 |
| Share of voice | 0.5% | 0.5% |
| Mentions this run | 3 | 3 |
| Positive in AI answers | — | 33% |
The stronger value in each row is marked with a ✓.
Visibility score trend
Weekly runs over the last 60 days
Retell AI 0pp · Sierra 0pp over 0 weekly runs.
Engine by engine
Retell AI leads on 1 of 3 engines
ChatGPT
AI Mode
Perplexity
Retell AISierra
Head to head in AI answers
0 engine answers name both brands
0Retell AI ranked higher
0Sierra ranked higher
Features, pricing & fit
| Dimension | Retell AI | Sierra |
|---|---|---|
| Pricing model | Usage-based | — |
| Entry price | Contact sales | — |
| Free plan | Yes | — |
| Deployment | Cloud platform, with enterprise on-premises deployment available | Managed and forward-deployed, with no self-serve option. |
| Compliance | HIPAA, SOC 2 Type II, GDPR, ISO 27001 | — |
| Support | Community and email support, 24/7 omnichannel support with dedicated portal (Enterprise), Dedicated implementation support (Enterprise), Named account manager (Enterprise) | — |
| Founded | 2023 | 2024 |
| Headquarters | Redwood City, California | San Francisco, California, United States |
| Employees | 51–200 | 1,001–5,000 |
| Funding | Seed · $5M raised | Series E, led by Tiger Global and GV |
| Best for | Businesses that run high call volumes in healthcare, insurance, financial services, logistics and similar fields, and teams that want to build and change voice agents themselves. | Businesses that want customer service AI agents across chat and voice, built by customer experience teams with or without engineering support. |
Plans side by side
Retell AI
Pay as you go$0per minute, $0.07-$0.31 for voice agents
EnterpriseCustomcustom pricing
Sierra
Pricing not available.
Pros and cons
Themes from the AI answers that mention each brand
Retell AI
- Highly rated by developers and SMBs
- One of the highest customer star ratings
Sierra
Profile in progress.
Data collected ·ChatGPT, Perplexity, Google AI Mode·coverage 100%·next run
Cite as: SlateIndex, “Retell AI vs Sierra”, https://slateindex.ai/compare/retell-ai-vs-sierra, data of Nov 3, 2026. Licence: CC BY 4.0.