Which one, by use case
| If you care about | Leads | Retell AI | Synthflow |
|---|---|---|---|
| Lowest cost at 1,000 minutes a monthNeeds a price at this volume from both vendors | Can't compute | $70 | Not computable |
| Lowest starting priceA starting price is missing for one or both | Can't compute | $0.07/minute | Contact sales |
| Trying it freeNo free plan found for either | Not found | Trial: $10 in free credits at signup, full platform access, no contract; then pay... | Not found |
| Buying without a sales call | Retell AI | Self-serve + sales | Sales-led |
| No long contract | Can't compare | no annual contract | Annual commitment for enterprise plan |
| Most voice agent platforms checks statedCounted from quotes on each vendor's site, not tested | Retell AI | 8 of 8 | 7 of 8 |
| Security reviewSOC 2, GDPR, HIPAA BAA and SSO, in the vendor's own words | Retell AI | 4 of 4 stated | 3 of 4 stated |
| Fewest price rises on recordFrom archived copies of each pricing page | Tie | 0 since 2024Q4 | 0 since 2024Q4 |
Each row is computed from the two records, with no overall winner. "Not found" means a record doesn't state it, so that row can't be decided.
Plans side by side
| Retell AI plan | Price | Included |
|---|---|---|
| Pay as you go (voice agents)/ min"$0.07-$0.31 / min for AI Voice Agents" | $0.07/minute | – |
| Pay as you go (chat agents)/ msg"$0.002+/ msg for AI Chat Agents" | $0.002/msg | – |
| Enterprise"Custom Pricingfor AI Voice Agents" | Quote | – |
Read from Retell AI's pricing page on Oct 29, 2026.
| Synthflow plan | Price | Included |
|---|---|---|
| Enterprise/year"Enterprise contracts start at $30,000 annually. Final pricing is scoped around call..." | Quote | – |
Read from Synthflow's pricing page on Oct 29, 2026.
Voice agent platforms checks
| Check | Retell AI | Synthflow |
|---|---|---|
| Inbound calls | Stated"Deploy your agent in minutes for inbound calls, outbound campaigns, web, or SMS." | Stated"Deploy AI voice agents across inbound and outbound call flows" |
| Outbound calls | Stated"Run outbound campaigns without stitching together another dialer." | Stated"Deploy AI voice agents across inbound and outbound call flows" |
| Phone numbers included | Stated"Retell Phone Numbers" | Stated"Synthflow Native Telephony" |
| Choose your AI model | Stated"Speech-to-speech LLM" | Not found |
| Choose the voice | Stated"Retell Platform Voices" | Stated"Shape the tone, voice, and workflows." |
| Public API | Stated"Webhooks and API Access" | Stated"API Docs" |
| Connects to your tools | Stated"Connect to any CRM, telephony, automation platform" | Stated"CRM, calendar, contact-center stack, webhook, API, and knowledge-source integrations" |
| HIPAA option | Stated"HIPAA / BAA" | Stated"Synthflow is fully compliant with SOC 2, HIPAA, GDPR, and ISO 27001" |
Fine print
| Term | Retell AI | Synthflow |
|---|---|---|
| Billing increment | nearest second"Each call is tracked to the nearest second." | Not found |
| Billed beyond usage | Not found | Excess usage beyond monthly usage limits is charged at the fees in the Subscription Plan; limits do not..."These Usage Limits are defined per month and do not roll over to the next month." |
| Contract | no annual contract"with no annual contract and no per-resolution charge" | Annual commitment for enterprise plan"Enterprise contracts start at $30,000 annually." |
| Refunds | fees non-refundable except as required by law or stated in terms"All fees are non-refundable except as required by law or as otherwise expressly provided for in these Terms." | Not found |
| Auto renew | auto-renews monthly unless workspace deleted or subscription items removed"Failure to do so will result in the automatic renewal of the Services for the Subscription Period, and you..." | Not found |
Security and your data
| Question | Retell AI | Synthflow |
|---|---|---|
| Trains AI on your data? | yes"to train the artificial intelligence models that support our Services or that support our business and..." | Not found |
| HIPAA (signs a BAA) | available"if the parties have executed a Business Associate Agreement ("BAA"), Protected Health Information is not..." | available"Synthflow’s infrastructure is certified across SOC 2, HIPAA, PCI DSS, and GDPR" |
| SOC 2 | SOC2 Type II"Fully compliant with HIPAA, SOC2 Type II, GDPR and ISO 27001." | yes"Synthflow’s infrastructure is certified across SOC 2, HIPAA, PCI DSS, and GDPR" |
| GDPR | compliant"Fully compliant with HIPAA, SOC2 Type II, GDPR and ISO 27001." | yes"Synthflow’s infrastructure is certified across SOC 2, HIPAA, PCI DSS, and GDPR" |
| Single sign-on | Enterprise"Custom SSO" | Not found |
The vendors' own words. We don't audit security claims. The full trust table.
Price history
No price changes on Retell AI's pricing page since 2024Q4, across 3 archived reads.
No price changes on Synthflow's pricing page since 2024Q4, across 7 archived reads.
From archived copies of each pricing page in the Internet Archive, one per quarter, in USD. All price changes.