Retell AI vs Sierra

Retell AI vs Sierra, compared side by side on 21 data points: what each one does, how big it is, what it has raised, the tech running each site, and what users report. We score both out of 100 on traction, team and visibility: Retell AI is on 63/100 and Sierra on 62/100.

Retell AI logo
Retell AIVoice AI agent platform handling more calls per second than the US 911 system, $60M ARR with a 35-person team.
Try Retell AI
Sierra logo
SierraSierra helps businesses build better, more human customer experiences with AI agents that can understand, reason, and take action across various channels.
Try Sierra

Where each one leads

Retell AI

  • agent readiness: 61/100 against 50/100

Sierra

  • headcount: 277 against 35
  • funding raised: $1.6B against $14.0M
  • LinkedIn following: 29,888 against 20,979

At a glance

MeasureRetell AISierra
What it isVoice AI agent platform handling more calls per second than the US 911 system, $60M ARR with a 35-person team.Sierra helps businesses build better, more human customer experiences with AI agents that can understand, reason, and take action across various channels.
CategoryAgentic AI, AI Agents, AI Voice Synthesis, AI Voice CloningAgentic AI, Conversational AI, Customer Service, AI Agents
Sells toBusiness modelB2BB2B
OfferingPlatformNot published
Founded20232023
HeadquartersSan Francisco, United StatesUnited States
StatusActiveActive

Size, funding and growth

MeasureRetell AISierra
Employees35277
Total funding$14.0M$1.6B
Latest roundSeedGrowth
ValuationNot published$10K
LinkedIn followers20,97929,888

StartupHub scores

Our own 0-100 ratings. They measure company strength and site quality, not which product suits you.

MeasureRetell AISierra
StartupHub scoreOur 0-100 rating63/10062/100
Traction66/10060/100
Team60/10050/100
Community8/1008/100
Search visibility48/10078/100
Quality68/10065/100
Agent readinessHow well an AI agent can read and act on the siteC (61/100)D (50/100)
Domain ratingLink authority, 0-10076/10073/100

Technology

Detected on each public site, so it reflects the marketing stack as well as the product.

MeasureRetell AISierra
HostingNot detectedVercel
CDNCloudflareCloudflare
CMSWebflowGhost
FrameworksNot detectedNext.js, Tailwind CSS
AnalyticsGoogle Analytics 4, Google Tag Manager, Mixpanel, Linkedin Insight +1 moreNot detected
Support stackNot detectedHubSpot

Product and pricing

MeasureRetell AISierra
Key featuresAI Voice Agent Platform, Auto-Sync Knowledge Base, Powerful Call Transfer, Easy Appointment Booking, IVR Navigation & Batch Calling, Compliance & ScalabilityAI Agent Deployment, Real-time Customer Support, Voice Communication Integration, Agent OS for Scalability, Actionable AI Integration, Robust Security & Compliance

Retell AI vs Sierra: common questions

Which is better, Retell AI or Sierra?

On our 0-100 score Retell AI rates higher (63/100 against 62/100). The score weights traction, team, visibility and profile completeness, so it reflects company strength rather than which product suits you. We compare the two on 21 data points above: read the rows that match what you are buying for.

How do Retell AI and Sierra compare on the numbers?

Retell AI leads on agent readiness (61/100 against 50/100). Sierra leads on headcount (277 against 35), funding raised ($1.6B against $14.0M), LinkedIn following (29,888 against 20,979).

Read the full Retell AI review and pricing or the Sierra review and pricing. You can also browse other Retell AI alternatives we track.