Sistava

Synthflow

No-code voice AI agent platform for SMEs and agencies

About Synthflow

Synthflow is a no-code platform for building AI voice agents with drag-and-drop flows, handling inbound/outbound calls, appointments, and lead qualification. It targets SMEs and agencies with white-label options. Sistava is a full workforce platform where voice is one channel among many, with team hierarchy, persistent memory, thousands of integrations, and multi-function employees.

Platform details

Official website

What does Synthflow actually do?

Synthflow is a no-code voice agent platform that lets non-developers build phone agents through a visual builder, point them at a knowledge base, and deploy them on inbound or outbound numbers. The platform handles speech-to-text, language model inference, text-to-speech, and telephony, and charges per second on successful calls only. The product is positioned squarely at SMBs and agencies that want voice agents without hiring engineers. A typical flow involves uploading documents to a knowledge base, picking a voice, writing instructions in plain English, and connecting a number, all from a web dashboard. For more advanced teams, an API and webhooks are available, but the headline experience is no-code. Where Synthflow sits in the category is one notch above raw infrastructure products like Bland or Retell. The trade is opinionated defaults in exchange for less control. For voice-only use cases that fit those defaults, the time to first working agent is short. For multi-channel work that spans phone, email, and research, a workforce platform like Sistava covers a broader surface, while Synthflow stays focused on the call.

How much does Synthflow cost?

Synthflow recently moved to a fully pay-as-you-go model. The voice engine costs around $0.09 per minute, the LLM adds $0.02 to $0.05 per minute, and telephony adds up to $0.02 per minute, putting the all-in cost somewhere between $0.11 and $0.16 per minute. Failed calls are not billed, so outbound campaigns with low pickup rates do not bleed budget the way they do on some competitors. Add-ons include performance routing at $0.04 per minute, extra concurrency at $20 per concurrent call per month, and a phone number at $1.50. Older tiered subscriptions (Starter at $29 per month, Pro at $99, Growth at $449, Agency at $899) remain available for teams that prefer a fixed monthly cap. For high-volume buyers, a custom enterprise tier is available at 10,000+ minutes per month with native telephony, unlimited concurrency, HIPAA compliance, and dedicated support. Compared to credit-based workforce platforms like Sistava that price across many channels at once, Synthflow's per-minute model is straightforward when voice is the only channel and harder to compare when it is not.

When does Synthflow beat the alternatives?

Synthflow wins when the buyer is a non-technical operator who needs a working voice agent live this week. The no-code builder, opinionated defaults, and pay-only-for-successful-calls billing make it the path of least resistance for SMBs, agencies, and operators who do not want to learn an API. Agencies are a particularly good fit. The platform supports a white-label posture, multi-client management, and a pricing structure that lets agencies pass through usage without subsidizing failed calls. For a small agency building voice agents for restaurants, real estate teams, or local services, the operational model maps cleanly to client billing. Synthflow loses when the team is comfortable in code and wants pick-your-own components, or when voice is only one part of a broader workforce need. Developers tend to prefer Retell or Bland for control; multi-channel buyers tend to prefer workforce platforms like Sistava where the same agent can also email, research, and update the CRM after the call ends.

Where does Synthflow fall short?

Synthflow is voice-first by design and does not attempt to be a broader agent platform. There is no native chat surface, no built-in email handling, and no shared work history that spans channels. Teams whose workflows cross phone, email, and CRM need to glue tools together externally. The second gap is depth of customization. The no-code abstraction is excellent for common patterns and gets thinner as use cases get unusual. Complex tool-use, multi-step reasoning over external data, or non-standard telephony setups bump into the platform's ceiling faster than on a code-first product like Retell. Third, the all-in per-minute cost between $0.11 and $0.16 can stack up faster than buyers expect when usage scales, especially with concurrency add-ons at $20 per call per month. Buyers comparing to flat credit models on workforce platforms like Sistava should run the numbers at projected volume rather than at pilot volume, because the lines cross sooner than the sticker rate suggests.

How does Synthflow handle no-code agent building?

Synthflow's no-code builder is the headline feature. Users upload documents to a knowledge base, write instructions in plain English, pick a voice from a curated list, and attach a phone number, all from a web dashboard. The opinionated defaults mean a basic agent is live in under an hour for someone who has never built one before. Behind the visual layer, Synthflow exposes function calling, webhooks, and an API for teams that outgrow the no-code surface. That escape hatch is important because real production voice agents almost always need to call a CRM, look up an order, or trigger an external workflow. The handoff from no-code to API is documented and works. What the no-code builder does not do is operate across channels or coordinate with other agents. A workforce platform like Sistava treats the agent as an employee that can take a task, do work across voice and other channels, and report back, which is a different abstraction. Synthflow's strength is being the fastest way to put a voice on a phone number; the workforce abstraction lives somewhere else.

Comparison