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Synthflow vs Vapi (2026)

Comparing Synthflow and Vapi? Both are AI Agents & Chatbots and Voice & Phone AI tools in the directory, which is why buyers put them on the same shortlist. Below is a side-by-side look at pricing and an estimated monthly bill, channels, compliance claims, and integrations, plus when each is the better fit, so you can pick on the facts rather than either vendor's own sales page.

At a glance

Conversations/mo

% handled by AI

Agent seats

Price it at my volume

Estimates assume 5,000 conversations a month, 60% handled by AI and 10 agent seats, at each vendor's published list price (the cost calculator's model); treat them as a floor, not a quote. Compliance rows are what vendors publicly claim, and “Not verified” means we have not confirmed that fact yet, not that the tool lacks it.

Choose Synthflow or Vapi?

About Synthflow

Synthflow is a platform for building AI voice agents that answer and place phone calls, and since 2026 it also runs chat agents from the same workflows. Agents are built in a visual Flow Designer, where subflows act as specialised agents for separate tasks and steps call your APIs, and are deployed into customer service, receptionist, appointment booking, IVR, lead qualification and outbound campaigns. It connects to more than 200 tools, including contact center platforms (Genesys, Five9, 8x8, RingCentral, Cisco, Avaya), CRMs (Salesforce, HubSpot, Zoho, Freshworks), helpdesks (Zendesk, Intercom) and telephony carriers such as Twilio, Telnyx and Vonage. Synthflow claims more than 30 languages.

Two things distinguish it from Retell and Vapi, the developer-first voice platforms it is usually compared with. First, Synthflow runs its own telephony network, which it says keeps latency under 100 milliseconds and lets it place voice infrastructure in the regions a customer needs, while still accepting your own carrier or SIP trunk. Second, it has packaged the agent lifecycle into what it calls the BELL framework (Build, Evaluate, Launch, Learn): agents are tested in a Test Center with simulated calls before going live, and Auto-QA scores every live conversation afterwards so the results feed the next version. Forward-deployed engineers handle enterprise rollouts. The trust center lists SOC 2 Type 2, ISO 27001, ISO 42001, HIPAA, PCI DSS, GDPR and EU AI Act coverage, which is unusually broad for a company this young.

Synthflow was founded in Berlin in 2023 by Hakob Astabatsyan (CEO), Albert Astabatsyan and Sassun Mirzakhan-Saky. It raised a pre-seed led by Atlantic Labs, a seed led by Singular in 2024 and a $20 million Series A led by Accel in June 2025, for $30 million in total, and has about 70 employees. It says more than 130 enterprises use it. The most notable deployment is a partnership with Freshworks that puts Synthflow voice AI inside Freshcaller, Freshdesk and Freshservice, automating up to 65 percent of routine voice requests; 8x8 and AVANT signed channel partnerships in 2026. Customer stories include Thryv, Medbelle, Euro Paper and Niagara Region Transit.

Synthflow has moved upmarket: its pricing page now lists only enterprise contracts, starting at $30,000 a year and scoped around call volume, concurrency, telephony and integrations. Choose Synthflow if you want enterprise voice agents with telephony, testing and QA handled by one vendor, especially if you already run Freshworks or 8x8. Skip it if you are a small business or developer wanting to pay by the minute and build yourself; Retell or Vapi publish usage pricing and let you start without a contract.

Read the full Synthflow listing →  ·  See Synthflow alternatives →

About Vapi

Vapi is a developer platform for voice AI agents. Rather than selling a finished support bot, it sells the orchestration layer: an API and SDKs that wire together speech-to-text (Deepgram and others), any major LLM (OpenAI, Anthropic), text-to-speech (ElevenLabs, PlayHT, Cartesia), and telephony (Twilio, Vonage, Telnyx) into a low latency phone agent. Support teams meet Vapi indirectly, as the engine behind custom-built inbound support lines, appointment desks, and agencies' white label voice products.

Founders Jordan Dearsley and Nikhil Gupta went through Y Combinator in 2021 with a productivity app called Superpowered, then pivoted to voice infrastructure in 2023 after Dearsley built himself an AI phone bot to think out loud with. It worked: Vapi reports over a million developers and a billion calls handled. It raised a $20 million Series A led by Bessemer in December 2024, then a $50 million Series B in May 2026 at a $500 million valuation, roughly $72 million total. Amazon chose Vapi for its Ring division after evaluating over 40 rivals.

Pricing starts at $0.05 per minute for the platform itself, with SMS at $0.005 per message. Provider costs (speech, LLM, voice, telephony) are passed through at cost, or drop to zero if you bring your own API keys. Realistic all in costs run $0.07 to $0.25 per minute. Ten concurrent calls are included, extra lines cost $10 monthly, and compliance add-ons are priced like enterprise software: HIPAA at $2,000 monthly, zero data retention at $1,000 monthly.

Choose Vapi if you have engineers and want maximum control over every layer of a support voice agent, with the freedom to swap providers as models improve. Skip it if nobody on your team writes code, or you want a vendor accountable for resolution rates rather than infrastructure.

Read the full Vapi listing →  ·  See Vapi alternatives →

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