Synthflow

Agent Frameworks active ★ 4.5 usage-based · $0.09/min Free tier available Verified Mar 2026

Synthflow is an enterprise-ready voice AI agent platform that automates inbound and outbound phone calls for businesses. It handles appointment scheduling, lead qualification, and customer support through natural conversational voice technology. The platform features a visual flow designer, built-in telephony, and a knowledge base system, powering over 65 million voice calls per month across 30+ countries.

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Key Features

Visual Flow DesignerDrag-and-drop flow builder for designing conversation logic, branching, and agent behavior without code.

In-House TelephonySynthflow-native telephony infrastructure available on Enterprise, plus Twilio integration and bring-your-own options.

Real-Time Appointment BookingAI agents can check calendar availability and book appointments during live calls.

Knowledge BaseUpload documents and data sources so voice agents can answer questions with accurate, grounded information.

White-Label & Reseller ToolkitCustom domain, branding removal, and reseller tools for agencies deploying voice AI for clients.

Multi-Language SupportDeploy voice agents across 30+ countries with multi-language capabilities.

Use Cases

Automating appointment scheduling and confirmations via phone
Qualifying inbound and outbound leads with AI voice agents
Providing 24/7 customer support without human agents
Running outbound calling campaigns at scale
White-labeling voice AI for agency resale

Pros

No-code flow designer makes building voice agents accessible to non-technical users
In-house telephony infrastructure with sub-600ms latency option
Supports GPT-4.1, GPT-5, GPT-5.1, and bring-your-own LLM
White-label and reseller toolkit available ($2,000/mo on PAYG, included on Enterprise)
SOC2, GDPR, and HIPAA (Enterprise) compliance
4.5 stars across 1,000+ reviews on G2

Cons

Per-minute costs stack up (voice + LLM + telephony + add-ons) making total cost hard to predict
Native telephony only available on Enterprise plan; PAYG uses Twilio
White-label is $2,000/month on pay-as-you-go
Less customizable at the code level than developer-first platforms like Vapi

Pricing

Plan	Price
Pay As You Go	Free
Enterprise	Free

Works With

ZapierConnects to Zapier for triggering workflows after calls (CRM updates, follow-ups, notifications).MakeIntegrates with Make for automating post-call actions and data routing.n8nCan trigger n8n workflows for custom automation after voice interactions.

Comparisons

Synthflow vs Bland AIBoth target phone automation, but Synthflow offers a visual flow builder and built-in telephony while Bland AI focuses on enterprise API access.Synthflow vs VapiSynthflow is no-code with a visual flow designer, while Vapi is API-first and developer-focused. Synthflow includes its own telephony; Vapi requires you to bring your own. Synthflow targets business users; Vapi targets developers.