A Synthflow alternative you create by describing it.
Synthflow gives you a no-code flow builder for enterprise phone agents. A Callable starts with a plain-language brief.
Where Synthflow fits.
Synthflow is an enterprise voice AI platform built around a no-code visual Flow Designer, with prebuilt industry templates, 200+ integrations, and its own telephony infrastructure, aimed at call centers and regulated industries such as healthcare and financial services.
How the two compare.
Six differences from what both sides publish.
| Aspect | Callable | Synthflow |
|---|---|---|
| How you build it | Describe the line in plain language. The builder asks what it can't infer and drafts it. | Built through Synthflow's no-code visual Flow Designer, with prebuilt industry templates and modular subflows. |
| Where it runs | Your own phone number, on its own dedicated server. | Synthflow's own cloud platform, with in-house telephony infrastructure; enterprise plans add SIP trunking or other approved telephony. |
| Cost visibility | Every call has an itemized receipt: carrier, transcription, model, and voice, each with its source and rate. | No published per-minute rate. Enterprise contracts start at $30,000 a year, scoped to call volume, concurrency, and telephony after a sales call. |
| Testing before live | Drafts run through scripted test conversations before publishing. | An AI sandbox runs simulated calls to measure accuracy before launch, per Synthflow's own site. |
| Who it's for | Teams who want to describe a phone line, not maintain one. | Enterprise call centers and regulated industries such as healthcare and financial services, per Synthflow's own site. |
| Code required | None. Describe it, review the draft, publish. | No to start. The no-code Flow Designer is the default; API integrations are available for enterprise. |
Sources: synthflow.ai — homepage (checked 2026-09-24) · synthflow.ai/pricing (checked 2026-09-24) · retellai.com/pricing (checked 2026-09-20)
Where to go next.
Describe your line
Tell the builder what calls it should take. It asks what it can't infer, then drafts the line.
Start building →See what it costs
Every call prints a receipt with the source and rate for every layer.
View cost →Watch how it’s built
From brief to published line.
See how it works →
Also compare: Vapi · Retell AI · Bland AI · Bland AI vs Vapi · Retell AI vs Vapi · All platforms compared
Straight answers about switching from Synthflow.
Seven questions people ask before moving a line off Synthflow.
No. Describe what it should answer and refuse, and what callers need to leave behind. The builder asks what it can’t infer, then drafts and tests the line. There’s no Flow Designer canvas to rebuild and no subflow logic to recreate first.
Not Synthflow’s own Flow Designer defaults specifically, but Callable’s own provider list, per line: OpenAI, Gemini, or Grok to decide what to say; Soniox or Deepgram to hear the caller; Cartesia, ElevenLabs, or Inworld to speak the reply; Twilio or Telnyx to carry the call. The builder sets a default stack; any of the four can be swapped.
On its own dedicated server, shared with no other Callable, not an agent inside Synthflow’s own cloud telephony infrastructure.
Yes, in place of Synthflow’s own AI Sandbox, which runs simulated calls before launch. Before publishing, a draft runs six graded caller scenarios as text conversations through the builder’s playground path, and every transcript is graded. Nothing goes live until you press publish, and every publish is recorded.
About $0.062 a minute on the default stack, at the providers’ published rates, itemized by layer on every call: carrier, transcription, model, voice. See /cost. Synthflow doesn’t publish a per-minute rate. Enterprise contracts start at $30,000 a year, with the final price scoped to call volume, concurrency, and telephony after a sales call.
Buy a number in the dashboard and point your line at it. No rebuilding the Flow Designer routing a Synthflow number depends on. Once bought, it’s yours in the dashboard, whether you’re switching from Synthflow or starting fresh.
Synthflow doesn’t publish a per-minute rate; enterprise contracts start at $30,000 a year, scoped to call volume, concurrency, and telephony after a sales call. Retell AI publishes $0.07 to $0.31 a minute for voice agents, pay as you go, itemized on its own pricing page. Callable’s own default stack runs about $0.062 a minute, itemized by carrier, transcription, model, and voice, with no plan price and no annual contract.
About $0.062 a minute on the default stack, at the providers’ published rates, itemized by layer on every call: carrier, transcription, model, voice. See the price book →
For the full pricing comparison, the price book, a worked example, and how Callable compares to other platforms: How five platforms price AI voice agents · The full price book · Run the numbers in the calculator · Compare every alternative
Describe the line you need.