Retell AI: Low-Latency Voice AI Agents
Per Retell's homepage, Retell AI is "an LLM-powered voice AI platform that builds and deploys human-like AI agents to automate phone calls at scale." The pitch leans into latency: "with ~600ms latency, conversations stay smooth and fluent," and the company claims "independent benchmarks confirm Retell as the leader in responsiveness." The customer outcome stories on the site are concrete revenue and cost numbers, not vanity metrics.
The 30-second version
- What: LLM-powered voice AI platform with low-latency turn-taking
- Who: teams automating high-volume phone calls (scheduling, support, sales, collections)
- Price: $10 free credit to start; per-minute pricing thereafter
- Best at: conversational responsiveness, smooth turn-taking
- Verdict: pick Retell when latency and natural conversation flow are the priority
What Retell AI actually is
Retell AI builds and deploys voice agents that automate phone calls at scale. The platform handles speech-to-text, LLM reasoning, text-to-speech, and telephony in one stack. The latency claim (~600ms) and the "independent benchmarks" framing suggest the team prioritized turn-taking quality over breadth.
The customer outcomes on the homepage are unusually specific. Pine Park Health increased scheduling NPS by 38%. SWTCH cut support costs by over 50%. Medical Data Systems collects roughly $280,000 per month with only a 30% transfer rate (the rest of the calls are handled end-to-end by Retell). That last number is the kind of detail that signals real production deployment.
Key capabilities
- ~600ms latency for smooth turn-taking
- Independent benchmark claims of responsiveness leadership
- End-to-end voice stack: STT, LLM, TTS, telephony
- Inbound and outbound call automation
- $10 free usage to start
- Enterprise customer references with concrete revenue and cost outcomes
Pricing
Retell starts with $10 of free usage. Paid tiers are per-minute. See retellai.com/pricing for current rates.
Who Retell fits
- Teams automating high-volume customer-facing calls
- Sales and support orgs replacing phone agents at scale
- Healthcare and finance use cases where turn-taking responsiveness matters
- Builders who want to evaluate quickly with $10 of free usage
Who Retell does not fit
- Teams that need on-premise deployment (Bland is better)
- Workflows that need 1B-call enterprise scale (Vapi's footprint is larger)
- Solo operators with low call volume (cheaper SaaS tools exist)
Retell vs Vapi and Bland
| Axis | Retell | Vapi | Bland |
|---|---|---|---|
| Latency claim | ~600ms (claims leader) | Under 500ms | Not published |
| Free credit | $10 to start | Per-minute pricing | Contract-based |
| Deployment | Cloud | Cloud | Cloud + on-prem + VPC |
| Customer outcomes | 38% NPS lift, 50% cost cut, $280k/mo | Amazon Ring, GoHealth $10M+ saved | $40M added in 5 months |
| Best for | Low-latency turn-taking | Developer scale | Enterprise + compliance |
Full breakdown: Vapi vs Retell.
Pros and cons
Pros:
- Strongest latency benchmark claims in the category
- Specific revenue outcomes from named customers (not just engagement metrics)
- $10 free credit lowers the evaluation barrier
Cons:
- No on-prem option for compliance-heavy use cases
- Smaller marketing footprint than Vapi at the enterprise high end
- Less developer-customizable than Vapi in some areas
How I'd think about Retell on SellerShorts
For a SellerShorts tool builder shipping an AI scheduling assistant for Amazon agency owners or a Q&A bot for inbound seller calls, Retell's low latency makes the conversation feel like talking to a human. The $10 free credit is enough to test the use case for an afternoon. If the prototype works, the path to production is straightforward.
Try Retell
Get started with Retell
$10 free credit. Per-minute pricing after that.
Selling on Amazon and want AI tools sized for your stack? See the Amazon AI hub.
Frequently asked questions
What is Retell AI?
Per the Retell homepage, Retell AI is 'an LLM-powered voice AI platform that builds and deploys human-like AI agents to automate phone calls at scale.' The platform focuses on low-latency turn-taking, with ~600ms response time and independent benchmark claims of leadership in responsiveness.
Is Retell free to try?
Yes. Retell offers $10 of free usage to start. After that you pay per-minute through paid tiers. The free credit covers enough conversations to evaluate whether the platform fits your use case.
Retell vs Vapi: which is faster?
Both claim to lead on latency. Vapi cites under 500ms; Retell cites ~600ms with 'independent benchmarks' confirming leadership in responsiveness. In practice the gap is real but small. The right pick depends on your other needs (Vapi for scale, Retell for proven low-latency benchmarks).
What outcomes do Retell customers report?
Customer quotes on the homepage include Pine Park Health ('increased scheduling NPS by 38%'), SWTCH ('cuts support costs by over 50%'), and Medical Data Systems ('collecting ~$280,000 per month with only a 30% transfer rate'). The pattern across customers: real revenue or cost savings, not just engagement metrics.