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Retell AI vs Synthflow
What each vendor publishes about price, minutes, compliance and integrations, side by side. Checked Oct 26, 2026. We have not tested either product; every fact links back to its source on the vendor page.
The differences in short
- Retell AI publishes a monthly price (Free); Synthflow does not.
- They name no industry in common (neither names a specific industry).
- Shared integrations: API.
- Retell AI states hipaa; Synthflow does not say so on the pages we checked.
- Synthflow states crm integration; Retell AI does not say so on the pages we checked.
- BAA: Retell AI say they sign one.
Side by side
| Fact | Retell AI | Synthflow |
|---|---|---|
| Type | Voice agent platform | Voice agent platform |
| Starts at | Free | Quote |
| Billing model | Pay as you go | Enterprise contract |
| Per-minute rate | $0.07 | Not published |
| Price per call | Not published | Not published |
| Included on entry plan | Not published | Not published |
| Overage | Not published | Not published |
| Free plan / trial | $10 free credits | Not stated |
| HIPAA | BAA available | Not stated |
| Languages | Not published | Not published |
| Human backup | Transfers to your team | Transfers to your team |
| Spanish / bilingual | Not stated | Not stated |
| After-hours / 24/7 | Not stated | Not stated |
| Appointment booking | Yes (vendor states it) | Yes (vendor states it) |
| CRM integration | Not stated | Yes (vendor states it) |
| Build style | No-code and API | No-code / low-code |
| Telephony included | Yes | Yes |
| Bring your own carrier / SIP | Yes | Yes |
| Choice of LLM | Yes | Not published |
| Choice of voice provider | Yes | Not published |
| Latency (vendor claim) | ~600ms | Sub-100 ms telephony latency |
| Concurrency | 20 free concurrent calls; no cap on Enterprise | Custom concurrency planning (enterprise) |
| Outbound calling | Yes | Yes |
| White label | Not published | Yes |
| Contact-center integrations | Not published | Cisco, Avaya, Genesys, RingCentral, Salesforce, HubSpot |
| Integrations | API, Call transfer, Appointment booking | Cal.com, CRM, Contact-center stack, Webhooks, API, WhatsApp |
| Industries named | General small business | General small business |
| Contract | Not published | Not published |
| Checked | Oct 26, 2026 | Oct 26, 2026 |
| Website | Visit | Visit |
Summaries
Retell AI: Pay-as-you-go voice agent platform for developers; component pricing for infra, voices, LLM and telephony.
Synthflow: Enterprise voice AI platform for building phone agents with native telephony, SIP and contact-center integrations.
Keep comparing
Sources: Retell AI listing and Synthflow listing, each with the vendor URLs we read. Spotted an error? Send a correction.