SSynthflow

Synthflow suits agencies, BPOs and contact centers that run AI phone agents for many clients and want to present them as their own service. The agency Partner workspace adds subaccounts, a custom domain, branding, per-client limits and rebilling, and the platform lists SOC 2, HIPAA, PCI DSS, GDPR and ISO 27001.

Prices come from Synthflow’s sales team, so smaller agencies will need a quote before they can budget. In return they get a platform that reports more than 1 million calls a day and published results from Freshworks and Medbelle. Synthflow scores 8.3/10 on our scale.

Synthflow by the Numbers

Synthflow’s June 2025 funding release and its agency page supply these figures.

Freshworks is the name that carries weight. A software company with its own support products automating up to 65% of routine voice requests on Synthflow suggests the agents hold up in real support queues.

The 60-day BPO deployment at 600,000 calls a month matters for agencies too. It shows the platform can take a large client live in about two months, which helps an agency set a realistic timeline for its own enterprise clients.

Accel’s lead role in the Series A, with plans to open a US office, signals a push into US enterprise accounts. Agencies should expect the product to keep moving toward larger customers.

Three founders started the company in 2023: chief executive Hakob Astabatsyan, Albert Astabatsyan and Sassun Mirzakhan-Saky. The funding release describes white-label voice agents as part of the product from the start.

How Synthflow Runs Voice Agents for Many Clients

Synthflow combines a voice agent builder with a multi-tenant agency layer. The agency builds once and deploys across clients.

Building a Voice Agent

Agents are built without code. Common jobs include customer support, appointment scheduling, inbound lead qualification, real-time information collection and transfers from the AI to a person. Synthflow claims response latency under 500 milliseconds and lists English, Spanish, German, Portuguese and French.

Connecting Phone Systems and Business Tools

Telephony connectors cover Genesys, Twilio, Avaya, Five9, RingCentral, 8×8 and Cisco, and SIP trunk integration is part of the enterprise package. On the business side, Synthflow lists Salesforce, HubSpot, Zendesk, Freshdesk, ServiceNow, Jira, Zapier, Cal.com, Zoom and WhatsApp. Call transcripts and recordings can be pulled through the API, Zapier, HubSpot or GoHighLevel.

Voice and Chat From One Agent

The same agent can answer calls and chats with shared logic and memory. For an agency, that means one build covers a client’s phone line and its website or WhatsApp chat. Chat usage is metered at 5 AI messages to one minute, so both channels draw from the same allowance.

Live Transfers

When a caller needs a person, the agent transfers the call live. Agencies set transfer rules per client, such as routing billing disputes to the office or emergencies to an on-call number.

Setting Up the Partner Workspace

Agency workspaces have a Partner section under Settings. From there the agency sets its brand name, logo, theme, color and help-docs link, and can host the white-label app on its own domain.

Managing Client Subaccounts

Each client gets a subaccount. The agency controls permissions, including who can edit agents, and sets limits for new and existing subaccounts. Products let the agency import agents, workflows, phone numbers and actions into a client’s subaccount, which speeds up repeat deployments. Analytics compare minutes, calls and average call length across clients.

Rebilling Clients

The agency allocates minutes to each subaccount and sets its own prices. Where agency billing is turned on, subaccount charges follow the agency’s pricing settings and its connected Stripe account.

Reporting to Clients

Call logs and analytics are available per subaccount, and agencies can compare total minutes, calls and average duration across clients. Those numbers feed a monthly client report and show which clients are close to their minute limits.

A Home Services Client, Step by Step

An agency onboarding a plumbing company might create a subaccount, import its standard booking agent and phone number setup, connect the client’s Cal.com calendar and set a monthly minute limit. The agent answers calls, books jobs and transfers emergencies to the on-call plumber. The agency reviews subaccount analytics each month and bills the client through Stripe at its own rate.

The agency does most of the work once, in its own workspace, and reuses it. A tested booking agent, a phone number setup and a set of actions can be imported into each new client’s subaccount and then adjusted for that client’s hours, services and staff.

Synthflow Quotes, Metering and Agency Billing

Synthflow does not publish a self-serve price list on the pages above. The enterprise package, sold through sales, includes the items below, and the documentation explains exactly how usage is counted.

Counting Minutes for Three Workloads

These examples use Synthflow’s metering rules. Multiply by the per-minute rate in your agreement to get a cost.

• Outbound campaign: 1,000 dials with 400 unanswered and 600 answered calls averaging 2 minutes 10 seconds. Unanswered calls add about 33 minutes, answered calls 1,300 minutes, for about 1,333 billable minutes.
• Chat assistant: 10,000 AI messages count as 2,000 usage minutes.
• Agency with ten clients: if each client uses 500 minutes, the agency is billed for 5,000 minutes and recovers them through its own client prices.

Billing thresholds are triggers for alerts and invoices, not spending caps, so agencies should set subaccount limits to protect themselves.

Questions for the Synthflow Sales Call

• What is the per-minute rate, and does it change with volume?
• Which allowances are included, and does unused time carry over?
• How is Test Center simulation time billed?
• Which plan includes the agency Partner workspace and Stripe rebilling?
• How many concurrent calls are included before enterprise terms apply?

Written answers to these five questions let an agency price its own client packages with a known margin.

Keep an eye on concurrency as well. The enterprise package lists unlimited concurrent calls, which matters for clients with call spikes, such as a utility during an outage or a clinic on Monday mornings. Agencies on smaller agreements should ask what happens when many calls arrive at once.

Synthflow Compared With Retell AI, Stammer.ai and HighLevel

Synthflow is the choice in this group for agencies whose clients ask for HIPAA, PCI DSS or ISO 27001 paperwork. Stammer.ai and HighLevel publish lower entry prices for smaller clients, and Retell publishes per-minute rates for teams that build their own stack. See more on our white-label agent platforms and voice agents pages.

Price transparency is the main trade-off. Synthflow asks agencies to talk to sales, while the others in the table publish entry prices. Agencies that sell large contracts may accept that in exchange for certifications and contact-center connectors.

Agencies and Operators That Fit Synthflow

• Agencies with healthcare or finance clients: HIPAA, PCI DSS and SOC 2 listings answer common procurement questions.
• BPOs and contact centers: connectors for Genesys, Five9, Avaya and Cisco fit existing phone systems.
• Agencies scaling repeat deployments: importing agents, workflows and numbers into subaccounts saves setup time per client.
• European agencies: Synthflow is based in Berlin, offers EU hosting and lists German among its languages.
• Zoom-based clients: Synthflow lists Zoom among its integrations, which suits clients on Zoom Phone.

Each of these groups gains most from the parts of Synthflow that are hard to build alone: certified hosting, contact-center connectors and a multi-tenant workspace with per-client limits.

When a Self-Serve Voice Platform May Fit Better

• New agencies with a few small clients: a published $99 white-label plan such as Stammer.ai’s is easier to budget.
• Markets outside the five listed languages: confirm language support before selling.
• Developers who want a raw per-minute API price: Retell AI publishes one.
• Agencies that only sell chat: Synthflow’s strengths are on the phone, and a chat-first white-label tool may cost less.

Synthflow Migration, Metering and Contract Details

Synthflow’s agency tools were moving to a new app, and subaccount pages opened on a separate fine-tuner.ai domain during the move. Agencies should confirm which interface clients will use and whether branding carries across both. Ask for a demo of the client view before the first client logs in.

Unanswered outbound calls are not free. Each no-answer or voicemail hang-up counts as 5 seconds, which adds up in large dialing campaigns with low pickup rates.

Billing thresholds do not stop spending. Agencies should set limits per subaccount so one busy client does not run up the agency’s bill.

Carryover of unused allowances exists only if it is in the agreement, and enterprise rates and invoice terms are custom. Agencies should get minute rates, allowances, carryover and Stripe rebilling terms in writing.

Test calls run through the Test Center are measured separately from live usage. Ask how simulations are billed before running large test suites.

Plan the client handover. If an agency later moves a client off Synthflow, it will want call logs, transcripts and recordings. Transcripts and recordings can be pulled through the API, Zapier, HubSpot or GoHighLevel, so set up an export early.

Synthflow Funding and Partnership News

• June 24, 2025: Synthflow raised a $20 million Series A led by Accel, bringing total funding to $30 million, to open a US office and expand its enterprise voice platform.

Synthflow Suits Agencies Selling Voice AI to Regulated Clients

Synthflow earns 8.3/10 on our scale. Its agency Partner workspace, wide telephony and CRM integrations and a long list of certifications count in its favor, and published results from Freshworks and Medbelle show the agents working in real queues. Medbelle reported 2.5 times more qualified appointments. It could publish self-serve prices for smaller agencies and finish the move of subaccount tools to its new app.

For agencies and BPOs whose clients run large call volumes or need compliance paperwork, Synthflow belongs on the shortlist. Agencies starting out with small local clients may prefer a platform with published entry prices and add Synthflow when larger contracts arrive. Either way, a pilot with one client, a fixed minute limit and a written rate sheet is the safest first step.

Agency Owners Ask About Synthflow

Does Synthflow Offer White Label for Agencies?

Yes. Agency workspaces have a Partner section with subaccounts, permissions, per-client limits, a custom domain, branding and rebilling through the agency’s connected Stripe account.

How Much Does Synthflow Cost?

Plans and rates come from Synthflow’s sales team. Calls are measured per second, unanswered calls count as 5 seconds, and 5 AI chat messages count as one usage minute.

Is Synthflow HIPAA Compliant?

Synthflow lists HIPAA alongside SOC 2, PCI DSS, GDPR and ISO 27001, with EU and US hosting. Healthcare clients should request the related agreements during procurement.

Which Languages Do Synthflow Agents Speak?

Synthflow’s agency page lists English, Spanish, German, Portuguese and French.

How Does Synthflow Compare With Retell AI?

Retell AI publishes per-minute pricing and suits teams building their own agents. Synthflow prices through sales and adds an agency Partner workspace with subaccounts and rebilling.

Which Phone Systems Does Synthflow Connect To?

Synthflow lists Genesys, Twilio, Avaya, Five9, RingCentral, 8×8 and Cisco, plus SIP trunk integration on enterprise plans.

Who Founded Synthflow?

Synthflow was founded in 2023 by Hakob Astabatsyan, its chief executive, with Albert Astabatsyan and Sassun Mirzakhan-Saky. The company is based in Berlin.

Does Synthflow Work With GoHighLevel?

Synthflow’s agency page says call transcripts and recordings are available through GoHighLevel, as well as the API, Zapier and HubSpot. Agencies on GoHighLevel can pass call data into client accounts through that connection.