Why we compare PolyAI and Retell in 2025?

Leaders everywhere are feeling the do more with less squeeze - pressure to increase productivity while holding or even reducing the headcount.

Data backs it up. 77% of customer service leaders say executives are pressing them to deploy AI, a clear signal that orders to increase efficiency are coming from the top.

At the same time, Microsoft’s 2025 Work Trend Index describes “the infinite workday”, where AI is delivering gains but work is still outpacing old ways of working - fueling the need to update workflows, not just add new tools.

PwC’s 2025 CEO Survey reports early payoffs: roughly one-third of CEOs say generative AI has increased revenue and profitability already, with expectations of further gains next year; separate PwC coverage notes 56% of CEOs see more efficient use of working time thanks to generative AI.

The broader momentum of generative AI is undeniable as well. AI platforms drove ~1.13B referral visits in June 2025 to websites (up 357% year-over-year).

Against that backdrop, PolyAI and Retell AI keep showing up on shortlists because they represent the two dominant ways to deploy a voice receptionist: managed enterprise (PolyAI) and self-serve builder (Retell AI).

AI Voice is already used heavily. Pacific Gas and Electric company (PG&E’s) handles 4M+ calls/year and lifted CSAT +22% during outages with Poly AI. Meanwhile Retell’s transparent per-minute pricing and documented integration patterns have helped it spread fast across SMEs.

Both PolyAI and RetellAI are focused on Voice AI applications for business, but their approaches differ a lot. Let's compare :)

1. Managed service or self-serve platform?

Short answer

• ‍Choose managed service (PolyAI) when you need custom conversational design, deep integrations, and full data flow control (common case for enterprise)
• Choose self-service platform (Retell AI) when you want internal control, fast iteration, and clear usage economics (common case for SMEs)

Context

• PolyAI positions as an enterprise partner; the PG&E case shows scale, resilience, and measured CSAT lift under stress (classic managed-program traits).
• Retell is builder-first (APIs/SDKs, usage-based billing, free credits), making it attractive when you need to ship and iterate weekly.

What you'll get either way

• Safety and smart routing (protect sensitive info, define who gets priority, and set clear rules for when a human takes over);
• Real-world testing before launch (run 50–100 test calls)
• Analytics and weekly reviews (track problems solved without a human, missed calls, bookings, average call length, answer speed, and waiting time)
• Phone setup with backups – confirm internet phone lines and a backup route, decide whether to keep your current phone provider or use new numbers, and set clear rules for caller identity and failover.

2. Will it work with our phones and tools on day one?

Key terms you need to know first

• Bring Your Own Carrier (BYOC) - keep your current phone company and numbers, and connect the AI receptionist to that network instead of switching providers.
• Session Initiation Protocol (SIP) - the call-setup language used for internet calls. A SIP trunk is the digital version of a phone line that links your phone system to the public network.
• Private Branch Exchange (PBX) - a telephone system within an enterprise that switches calls between users on local lines.
• Code-switching - a situation when a speaker alternates between two or more languages. It's an edge case for AI voice agents.

What to check before go-live?

• Phone setup - decide to keep your carrier (BYOC) or start with vendor-provided numbers, and confirm a backup route for outages.
• Call flow fit - map how calls enter and exit your existing system (Interactive Voice Response, contact center, or PBX) and where the receptionist hands off to a human.
• Calendar and CRM integration - bookings, identity checks, tickets, and notes created automatically.
• Handoff rules - when a human must pick up, which callers are priority, and what message plays if no one answers.

Retell publishes step-by-step guides for connecting existing numbers via SIP, making BYOC practical for teams already on Twilio, Vonage, GoTo Communications, CallTrackingMetrics. PolyAI deployments are usually deep enterprise integrations across IVR and CRM.

Buyer tip: BYOC gives continuity and leverage - but you’ll own telephony ops (SIP failover, CNAM, STIR/SHAKEN). Using the vendor’s carrier starts faster; migrate to BYOC later if needed.

3. How natural is the voice across languages and accents in real calls?

Red flags to watch for when choosing an AI Receptionist:

• Long gaps before replies or words clipped at the start
• Flat, robotic tone or sudden jumps in volume
• Mispronounced brand/doctor names repeated multiple times
• Apology loops (“sorry, I didn’t get that”) on simple questions

Use the 2 videos below to judge with your own ears conversation in English. First one is from PolyAI. Second one is from Retell AI.

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Both PolyAI and Retell AI has quite natural voices in English. What about other languages?

PolyAI publicly claims “45 languages as standard”, while Retell AI publishes “31+ languages” with specific locales listed.

Let's do a deeper dive into 5 popular languages: Spanish, Portuguese, German, French, Russian. The evaluations below synthesize vendor docs, multilingual claims, and public demos.

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Takeaway: On these five, both vendors are viable. PolyAI leans on enterprise-grade claims about accent/slang robustness, while Retell publishes a concrete locales list (e.g., Spain/LatAm; PT/BR) and shows codeswitch behavior in docs - useful when callers mix languages.

Now let's see what other languages are supported by PolyAI and RetellAI beyond 5 popular ones.

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PolyAI’s voices are widely praised as “warm, natural, and human-like,” and the system elegantly handles multiple dialects in each supported language. Retell AI leverages top-tier text-to-speech engines (e.g. ElevenLabs) and  delivers very lifelike voices with smooth multilingual performance. Both platforms explicitly support the above languages and can discern regional accents (e.g. Iberian vs. Latin American Spanish, European vs. Brazilian Portuguese) in real-world customer interactions.

Now if you want the most accurate test, do these steps:

• Call each vendor’s public demo line if available and repeat the same script (booking, spell a surname, give an address).
• Run live tests with native speakers in your exact regions.
• Add background noise to mimic real-life scenario (TV playing, people chatting, etc. It's very important because most demos happen in isolated environment while real calls often have background noise)

4. What is the pricing of PolyAI and RetellAI?

What drives costs:

• Per-minute voice + LLM tokens (turn count, model choice).
• Numbers/SIP + carrier (or BYOC). Numbers usually cost less than $5/ month.
• Concurrency headroom for peaks (storms, launches)
• ‍Ops/QA to maintain accuracy and brand tone.

Retell publishes pay-as-you-go voice pricing from $0.07+/minute, with starter credits and concurrency allowances.

PolyAI engages via custom enterprise contracts (pricing is not public), aligning with managed integrations and large-scale customers.

5. What Customers Say?

Customers of Retell AI and PolyAI often highlight similar themes in their feedback on G2, Product Hunt and Trustpilot. Below is a comparison of key points from user testimonials for both companies.

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6. How to Choose the right AI Receptionist?

If you’re a large, regulated enterprise that needs polish, governance, and complex system wiring, PolyAI is a proven path.

If you’re a fast-moving SME or mid-market team with in-house builders, Retell gives you transparent costs, BYOC flexibility, and rapid iteration.

But what if you don't want to get locked into long-term PolyAI contract AND you don't want to spend precious time doing technical setup on Retell AI?

Parnidia’s AI Receptionist Christina can be a great fit for you. It's a middle ground between expensive managed service (Poly AI) and time-intensive solution of setting up your own voice agent on Retell AI. Parnidia developers set up everything for you while a dedicated QA manager maintains the reliability of AI Receptionist.

If you want a data-backed pilot plan mapped to your volumes and systems, book a strategy call below.