Retell AI wins on cost and production readiness for most small businesses in 2026: pay-as-you-go voice agents run $0.07–$0.31 per minute with $10 in free credits, 20 free concurrent calls, $2/month phone numbers, and SOC 2 Type I & II, HIPAA, GDPR, and ISO 27001 on every plan. Synthflow AI is the stronger pick if you want a no-code builder and subscription-style budgeting, with all-in usage around $0.15–$0.24 per minute, SOC 2 and GDPR coverage, though HIPAA is enterprise-only and there is no free tier. Choose Retell for lower per-minute cost and compliance by default; choose Synthflow for the simplest no-code setup.
Bottom line: Retell AI is cheaper per minute ($0.07–$0.31/min vs Synthflow's ~$0.15–$0.24/min all-in), includes compliance certifications on every plan, and offers $10 in free credits with 20 free concurrent calls. Synthflow remains a solid choice for small teams that prioritize a no-code builder and predictable subscription pricing.
TL;DR
- Retell AI charges $0.07–$0.31 per minute for AI voice agents on pay-as-you-go, with $10 in free credits and no commitments.
- Synthflow AI runs roughly $0.15–$0.24 per minute all-in on pay-as-you-go, with subscription plans that bundle essential features.
- Retell includes HIPAA, SOC 2 Type I & II, GDPR, and ISO 27001 on every plan; Synthflow covers SOC 2 and GDPR but reserves HIPAA for enterprise.
- Retell offers 20 free concurrent calls and $2/month phone numbers; Synthflow has no free tier.
- Retell cites ~600ms latency; Synthflow's latency is variable, with sub-600ms available via a paid add-on.
- Synthflow is ranked the best no-code builder for small teams in 2026 voice AI roundups.
- Retell supports 55 languages, branded calls, knowledge bases, warm transfer, and native SIP trunking.
Head-to-head
| Dimension | Retell AI | Synthflow AI |
|---|---|---|
| Pricing | Pay-as-you-go $0.07–$0.31/min; $10 free credits; $2/mo numberswinner | PAYG ~$0.15–$0.24/min all-in; subscription plans bundle essential features |
| Ease of use | Intuitive drag-and-drop workflows any PM can run, plus full API | Best no-code builder for small teams in 2026 rankingswinner |
| Features | Knowledge base, branded calls, real-time variable extraction, warm transfer, IVR/DTMF, batch calls, 55 languageswinner | Essential voice agent features included in subscription plans |
| Compliance | HIPAA (self-serve BAA), SOC 2 Type I & II, GDPR, ISO 27001 on every plan; automatic PII redactionwinner | SOC 2 and GDPR; HIPAA enterprise-only |
| Performance & latency | ~600ms end-to-end latency; proprietary turn-taking handles interruptionswinner | Variable latency; sub-600ms via paid add-on |
| Integrations & telephony | Native SIP trunking, bring-your-own telephony, custom LLM integration, webhooks and API accesswinner | No-code integrations suited to small-team stacks |
| Getting started | $10 free credits, go live in minutes, 20 free concurrent callswinner | No free tier; PAYG available |
Scores
Retell AI
retellai.com/ ↗Retell AI is a voice AI agent platform built for real-time phone conversations at production scale. It combines your choice of LLM (including OpenAI, Anthropic, and Google models) with voice engines like ElevenLabs, OpenAI, and Cartesia, and connects to public phone networks via native SIP trunking or bring-your-own telephony. The platform offers both a full API and a no-code drag-and-drop builder with conditional branching, warm transfer logic, and fallback nodes for unrecognized intents. Retell cites ~600ms end-to-end latency with a proprietary turn-taking model that handles interruptions and barge-in mid-sentence. Post-call tooling includes structured transcripts, sentiment scoring, custom extracted fields, and resolution tracking. Compliance is included by default rather than gated: HIPAA (self-serve BAA), SOC 2 Type I and II, GDPR, and ISO 27001 on every plan, plus automatic PII redaction for names, addresses, DOBs, passwords, and PINs. Published case studies include Pine Park Health reporting a 38% increase in scheduling NPS and Medical Data Systems handling 100% of inbound calls with a 30% transfer rate. It supports 55 languages, branded calls, verified phone numbers, and batch calling for outbound campaigns.
| Plan | Price | What you get |
|---|---|---|
| Pay as you go (AI Voice Agents) | $0.07/mo | $0.07–$0.31/min; $10 free credits; 20 free concurrent calls; full platform access; community and email support |
| Phone number | $2/mo | $2.00/month per number; toll numbers $5.00/month; verified numbers $10/month + $10 one-time setup |
| Add-ons | $8/mo | Extra knowledge base slots 10 free then $8/month each; concurrency $8/month per additional slot beyond 20 free; branded calls $0.10 per outbound call; batch calls $0.005 per dial |
| Enterprise | — | Customized pricing for high-volume users, potentially as low as $0.05/min |
Pros
- Lowest headline per-minute rate among compared platforms, from $0.07/min with no platform fees
- Enterprise-grade compliance (HIPAA, SOC 2 Type I & II, GDPR, ISO 27001) included on every plan, not gated behind tiers
- ~600ms latency with strong interruption handling, the threshold where callers stop noticing they are talking to AI
- $10 free credits, 20 free concurrent calls, and $2/month phone numbers keep entry costs minimal
- Both no-code builder and full API in one platform, with custom LLM and telephony flexibility
- Deep post-call analysis with sentiment scoring and extracted fields
Cons
- Requires some setup and configuration time, particularly for regulated deployments
- Per-minute usage model means costs scale with call volume, which can complicate budgeting for some businesses
- Add-ons stack up: branded calls ($0.10/outbound), extra knowledge base slots ($8/month each), extra concurrency ($8/month per slot)
Synthflow AI
Synthflow AI is a no-code voice AI platform aimed at small teams and businesses that want to launch AI phone agents without engineering resources. In 2026 voice AI platform roundups it is ranked as the best no-code builder for small teams, evaluated across inbound support, outbound sales, appointment scheduling, and multi-turn qualification. Its pricing model emphasizes transparency: subscription plans tailored to different business sizes bundle essential features within the subscription cost, which the vendor positions as avoiding hidden fees and making budgeting predictable, alongside a pay-as-you-go option. All-in usage costs run roughly $0.15–$0.24 per minute. On compliance, Synthflow covers SOC 2 and GDPR, but HIPAA compliance is reserved for enterprise plans, which matters for healthcare and other regulated buyers. Latency is variable rather than fixed, with sub-600ms performance available through a paid add-on — a meaningful consideration since ~600ms is roughly the threshold where callers stop noticing they are talking to AI. There is no free tier, though pay-as-you-go lets teams start without a subscription commitment.
Pros
- Best-in-category no-code builder for small teams without developers
- Subscription plans bundle essential features, making monthly costs predictable
- Transparent pricing positioned around avoiding hidden fees
- SOC 2 and GDPR compliance coverage
- Pay-as-you-go option allows starting without a large commitment
Cons
- All-in usage cost (~$0.15–$0.24/min) is roughly double Retell's entry rate
- HIPAA compliance is enterprise-only, limiting regulated-industry use
- No free tier to test the platform
- Latency is variable; sub-600ms performance requires a paid add-on
Pricing compared: per-minute rates, free credits, and add-ons
Compliance and reliability: what is included vs what is gated
Ease of use and fit for small teams
Which should you pick?
FAQs
How much does Retell AI cost per minute in 2026?
Retell AI charges $0.07–$0.31 per minute for AI voice agents on a pay-as-you-go basis, with $0.002+ per message for AI chat agents. Its own evaluations put the all-in run rate at roughly $0.08–$0.15 per minute. Phone numbers cost $2.00/month, toll numbers $5.00/month, and the pay-as-you-go plan includes $10 in free credits and 20 free concurrent calls. Enterprise pricing is customized and can reportedly go as low as $0.05/min for high-volume users.
How much does Synthflow AI cost?
Synthflow AI is reported at roughly $0.15–$0.24 per minute all-in on pay-as-you-go, alongside subscription plans tailored to different business sizes that bundle essential features into the monthly cost. The vendor positions this structure as transparent and free of hidden fees, which simplifies budgeting. There is no free tier, though the pay-as-you-go option lets teams start without a subscription commitment. Sub-600ms latency performance requires a paid add-on.
Which platform is better for HIPAA-regulated businesses?
Retell AI. It includes HIPAA with a self-serve BAA, SOC 2 Type I and II, GDPR, and ISO 27001 on every plan, plus automatic PII redaction for names, addresses, dates of birth, passwords, and PINs, and role-based access control. Synthflow AI covers SOC 2 and GDPR but reserves HIPAA compliance for enterprise plans, so a small healthcare practice on a standard plan would not have HIPAA coverage with Synthflow.
Do either Retell AI or Synthflow AI have a free trial or free tier?
Retell AI offers $10 in free credits with full platform access and no commitments, plus 20 free concurrent calls — enough to build, test, and run real calls before paying. Synthflow AI has no free tier, though its pay-as-you-go option allows starting without a subscription. If testing before committing matters to you, Retell's free credits make it the lower-risk starting point.
Which is easier to set up: Retell AI or Synthflow AI?
Synthflow AI is ranked the best no-code builder for small teams in 2026 evaluations, making it the simplest path for non-technical owners. Retell AI also offers a no-code drag-and-drop builder — evaluations note a working inbound agent can go live on a Twilio SIP trunk in under an hour — but it also carries full API, custom LLM, and telephony depth that involves more configuration decisions. Choose Synthflow for pure simplicity; choose Retell if you may need that extra control later.
Which voice AI platform is cheaper for a small business overall?
Retell AI is cheaper at the entry tier: $0.07–$0.31 per minute (roughly $0.08–$0.15 all-in) versus Synthflow's reported ~$0.15–$0.24 per minute all-in, and Retell's phone numbers cost $2.00/month. Retell also includes $10 in free credits and 20 free concurrent calls. The caveat is that Retell bills usage-based with itemized add-ons (e.g., $8/month per extra knowledge base slot or concurrency slot), while Synthflow's subscription bundles features — so if you strongly prefer a flat monthly bill, Synthflow's model may still suit you despite the higher per-minute rate.
Sources
- AI Phone Agent Pricing | Retell AI
- 8 Best Voice AI Platforms for 2026 (Tested and Ranked) | Retell AI
- Retell AI vs Bland AI: Pricing, Features & Value Compared
- How Much Should You Spend on AI Voice Agents? | Retell AI
- AI Voice Agent Pricing in 2026 | Retell AI
- Top 7 Voice AI Agents Fully Compliant with Global AI Regulations (2026 Guide) | Retell AI
- Bland AI Review (2026) | Retell AI
- AI Voice Agent Platform for Phone Call Automation | Retell AI
- Retell Market Competitor Overview
- AI Customer Experience: Strategy, Use Cases & Benefits 2026 | Retell AI