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Synthflow

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Voice agentindependentVerified 2026-07-01

Synthflow is a well funded no code voice agent platform with a visual flow builder, bring your own model keys, a testing center, and white label options for agencies.

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.

Vendor details

Canonical URL

https://synthflow.ai

Company status

independent

Use cases & customers

In practice

An agency builds white labeled voice agents in Synthflow's visual designer, resells them to clients under its own brand with subaccounts and billing, and launches each new agent in under a week.

A team picks its own language model and ElevenLabs voice in Synthflow, builds a multi branch call flow, then runs it through the Test Center against accuracy targets before putting it in front of customers.

A regulated enterprise deploys Synthflow with on premises multi region hosting and region based sub processing, running outbound campaigns over its own session initiation protocol trunks while meeting data residency requirements.

Sources & related URLs

Research notes

Score 9.5 (6F/7P/1N) [DEPTH CAVEAT: arguably 9.0 depth-adjusted; ties Regal/PolyAI at voice-lane top by strict axis-count but is BROADER-not-DEEPER - Mike's call whether to keep tie or drop to 9.0]. VOICE LANE co-leader (3-way tie w/ Regal + PolyAI). Well-funded NO-CODE voice agent platform; Berlin, founded 2023, $20M Series A (2025). 'Voice AI Operating System.' Especially popular for AGENCIES / white-label resale. Fewest gaps in lane (only 1 N). Fulls (6): Int (200+ integrations + CCaaS Cisco/Avaya/Genesys/RingCentral + CRM HubSpot/Salesforce/GoHighLevel + scheduling Calendly/Cal.com + API-connected builder + in-call actions), Orch (VISUAL FLOW DESIGNER drag-drop multi-branch conversation logic + configurable workflows + batch outbound campaigns; headline, BUT hits ceilings on very complex enterprise + no-code hides complexity when flows large), Sec (SOC 2 + PCI DSS + GDPR certified + HIPAA on Enterprise/BAA + encryption + audit logs + region-based hosting; note HIPAA Enterprise-gated), Dep (on-premise MULTI-REGION deployment + geo-based sub-processing + region-based hosting + data residency + controlled data ownership; Enterprise/advanced - more explicit than PolyAI's Dep so F), Model (BYOK - BRING YOUR OWN KEYS: choose LLM + TTS [ElevenLabs Turbo v2 default / Deepgram] + STT + voice cloning higher plans + 50+ languages; STRONGEST model flexibility in lane), Eval (TEST CENTER automated simulated-call testing vs KPIs pre-launch: accuracy/quality/compliance + BELL Framework + adversarial prompt testing + continuous learning; headline). Partials (7): Know (knowledge base connection BUT 'agents often rely solely on LLM memory, fail in complex multi-turn' per critics - weak grounding), HITL (call transfer + compliance guardrails via Test Center; formal oversight not detailed), Obs (Auto-QA + real-time conversation monitoring + transcripts/duration/outcome-tagging + analytics dashboard; BUT 'not as deep as enterprise competitors' per critics -> P not F), Mem (real-time personalization + contact records + within-call context; memory depth questioned), Pack (pre-built templates + visual builder + strong WHITE-LABEL/agency packaging: custom domain/branding/subaccounts/feature-controls/Stripe rebilling; not a marketplace), Trig (inbound + outbound BATCH campaigns + IN-HOUSE telephony network multi-cloud-redundancy/failover + BYO carrier/SIP; BUT phone number coverage LIMITED [US/CA/AU direct only, Twilio workaround Business-tier-locked] + multichannel DISPUTED [one 2026 source says voice-only vs own-site voice/chat/SMS claim] -> P not F), Ext (full API access + BYOK + API-connected builder + well-maintained docs.synthflow.ai + webhooks + white-label API; no documented SDK/MCP -> P for consistency w/ lane). N: Comp (no browser/computer use). NEGATIVES: 'speed/flexibility over deep operational control' (Orvera), not for very complex enterprise, support thin, BYOK real cost 2-3x advertised (#1 complaint), Vapi/Retell cheaper per-min, no native calendar booking (need Calendly/Cal.com), interface redesign criticized. PLUS: well-funded, ships regular updates, docs comprehensive, voice quality excellent (ElevenLabs default). Pricing self_serve + Enterprise sales_led: $0 to build/free trial; tiers vary across sources (Starter ~$29/mo, Pro ~$99, Growth ~$449, Agency ~$899) + PAYG ~$0.08/min marketing (real higher); Enterprise custom from $30k/yr. BYOK = provider fees EXTRA (LLM/TTS/STT), real cost 2-3x sticker. HIGH variable cost exposure. entry 20_to_49 ($29). public_exact. confidenceLevel high (own site + Retell/Orvera/Vellum/autocalls/G2/Zeeg + $20M funding + named certs/integrations).

Capability coverage

9.5 / 14 capabilities · 68%

Integrations & Tool CallingSynthflow integrates with more than two hundred tools including contact center systems Cisco, Avaya, Genesys, and RingCentral plus customer relationship management and scheduling tools through an application programming interface connected builder that takes actions during calls, so full.	Full
Workflow OrchestrationSynthflow's visual drag and drop flow designer builds complex multi branch conversation logic and configurable agent workflows and runs batch outbound campaigns, so full.	Full
Knowledge Grounding & RAGSynthflow can connect a knowledge base, but reviewers note its agents often rely mainly on language model memory and can struggle in complex multi turn dialogues, so partial.	Partial
Human Oversight & GuardrailsSynthflow supports call transfer and compliance guardrails validated in its Test Center, but a formal action approval gate is not detailed, so partial.	Partial
Security, Identity & GovernanceSynthflow is certified across SOC 2, PCI DSS, and GDPR with HIPAA available on its enterprise plan, plus encryption, audit logs, and region based hosting, so full.	Full
Observability & AuditabilitySynthflow provides Auto QA and real time monitoring of conversations plus transcripts, outcome tagging, and an analytics dashboard, but reviewers note the analytics are less deep than enterprise focused competitors, so partial.	Partial
Memory & State PersistenceSynthflow personalizes calls in real time and stores contact records, but reviewers question the depth of its memory in complex multi turn conversations, so partial.	Partial
Deployment & Data ResidencySynthflow offers on premises multi region deployment, geo based sub processing, region based hosting, and data residency controls for regulated buyers, so full.	Full
Prebuilt Agents, Templates & PacksSynthflow provides prebuilt templates and a visual builder plus one of the most complete white label agency offerings with subaccounts and rebilling, but not a marketplace of agents, so partial.	Partial
Triggers & Channel CoverageSynthflow handles inbound and outbound batch campaigns on its own telephony network or a team's own carrier or session initiation protocol trunks, but phone number coverage is limited and true multichannel is disputed, so partial.	Partial
Model Flexibility & RoutingSynthflow is bring your own keys, letting teams choose the language model, the text to speech engine, and the speech to text service, with voice cloning on higher plans and more than fifty languages, so full.	Full
APIs, SDKs & MCP ExtensibilitySynthflow offers full application programming interface access, a bring your own keys model, well maintained developer documentation, and webhooks, but a documented software development kit or Model Context Protocol surface is not evident, so partial.	Partial
Testing, Debugging & OptimizationSynthflow's Test Center runs simulated calls that measure accuracy, response quality, and compliance against a team's targets before launch, and an Auto QA loop feeds insights into the next version, so full.	Full
Browser & Computer UseSynthflow operates over voice and messaging channels and has no browser or computer use capability, so not documented.	Unable to verify

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Pricing

Free to build; Starter $29/mo; Ent from $30k/yr

Public — exactHigh variable cost

Verified 2026-07-01

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Data confidence: high