Synthflow

Synthflow is a no code platform for building and running AI voice agents that handle inbound and outbound phone calls. Founded in 2023 and headquartered in Berlin, it raised a twenty million dollar Series A in 2025 and has become one of the most popular options in the category, especially for agencies that want to resell voice agents under their own brand. Its pitch is speed and flexibility: a visual, drag and drop flow designer lets teams build complex multi branch conversations without code and take an agent from idea to live in a matter of weeks rather than months.

A defining choice is that Synthflow is bring your own keys. Teams supply their own model providers, choosing the language model, the text to speech engine, which defaults to a high quality ElevenLabs voice, and the speech to text service, with voice cloning available on higher plans and support for more than fifty languages. That flexibility is a genuine strength, though it also means the advertised per minute price excludes the provider fees, so real costs often run higher than the sticker rate. The platform integrates broadly with systems like Cisco, Avaya, Genesys, and RingCentral along with common customer relationship management and scheduling tools.

Synthflow leans into operational rigor for a self serve tool. A Test Center runs simulated calls that measure accuracy, response quality, and compliance against a team's own targets before any real customer calls, and once agents are live an Auto QA layer analyzes conversations and feeds insights back into the next version. It runs its own telephony network with redundancy and failover and also lets teams bring their own carriers or session initiation protocol trunks. On compliance it is certified across SOC 2, PCI DSS, and GDPR, with HIPAA available on its enterprise tier, plus audit logs and region based hosting, and it offers on premises multi region deployment for regulated buyers.

The reputation is breadth and ease over deep operational control. Reviewers praise how quickly agents go live and how complete the white label and agency features are, including subaccounts and billing, but flag that the platform is tuned for common workflows and can hit limits on very complex enterprise scenarios, that support can be thin, and that phone number coverage and true multichannel are narrower than the marketing suggests. Pricing is self serve and usage based, with published monthly tiers starting around twenty nine dollars and enterprise contracts starting near thirty thousand dollars a year. Synthflow suits agencies and teams that value fast deployment and model flexibility.