V
VRetell AI vs Synthflow
Pricing, features, platforms and who each one suits — side by side.
R
Choose Retell AI if…
- you want to trial it before paying
- you're in its core audience: customer service teams, healthcare and insurance providers
S
Choose Synthflow if…
- you're in its core audience: contact centers, bpos
Side by side
Feature Retell AI Synthflow
Pricing modelFree trialContact for pricing
Starting price——
Free plan
Free trial
API
Open source
PlatformsWeb, APIWeb, API
CompanyRetell AISynthflow AI
Full feature lists
R Retell AI
- Call transfer to human agents
- Appointment booking during calls
- Knowledge base answers for agents
- IVR navigation by pressing keypad options
- Batch outbound calling with branded caller ID
- Post-call analysis and AI quality assurance
- Choice of about 50 LLMs and several TTS providers
- Chat agents for web, in-app and SMS
S Synthflow
- Inbound and outbound AI phone agents
- Response time under half a second, with interruption handling
- Language switching during a call
- Warm handoff to human agents with full transcript
- Appointment booking, voicemail detection and SMS follow-ups
- 200+ integrations including Salesforce, HubSpot, Zendesk
- Pre-launch testing and staged rollout with approval
- US, EU and Latin America hosting regions
What you'd pay
The cheapest plan that fits, per month, billed yearly where the plan offers it.
Retell AI
Pay as You Go$0.07–$0.31/min (voice), $0.002+/message (chat)
EnterpriseCustom
Synthflow
EnterpriseCustom
Strengths and limitations
Retell AI
- $10 in free credits and 20 free concurrent calls
- Usage-based billing to the nearest second; failed calls are not billed
- Choice of many LLM and TTS providers
- Lists HIPAA, SOC 2 Type II, GDPR and ISO 27001 compliance
- Per-minute cost depends on model choices and add-ons, which makes it harder to estimate
- Concurrency beyond 20 calls costs $8 per concurrent call per month
- Phone numbers ($2/mo) and SMS ($20/mo) are billed as separate subscriptions
Synthflow
- SOC 2 Type II, ISO 27001, PCI DSS and HIPAA BAA compliance
- Works with major phone systems and SIP trunks
- White-label deployment with per-client workspaces
- Retention controls can delete recordings and transcripts after 30 days
- No free plan or trial
- Sold only as an annual enterprise agreement
- No published prices or per-minute rate
- SMS and WhatsApp limited to US workspaces
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Facts from each vendor's public pages. Editorial policy