AI that answers customers / job guide
No-code AI voice agent builders: build your own phone agent
The software handles
Lets you design and run your own AI phone agent: what it says, which tools it calls, and when it transfers.
Where people stay involved
You own the script, the testing and the escalation rules; someone must review calls and fix failures, which is the main ongoing cost.
Short answer. If you want to design the call flow yourself without engineers, start with Synthflow or Voiceflow; ElevenLabs Agents adds a visual builder on top of strong voice models. If you have developers and want control over every component and per-minute costs, Retell AI and Vapi are the developer platforms. Bland suits enterprises that want a self-hosted model stack.
Check these before you choose
- Who builds it. Visual builders let operations staff change call logic; developer platforms need engineers but give control over models, voices and costs.
- Telephony. Check whether it uses its own numbers, your Twilio account, or your PBX over SIP, and how transfers to your staff work.
- Real per-minute cost. Usage pricing often adds model, voice and telephony costs to a platform fee. Ask for an all-in estimate at your volume.
- Compliance evidence. For health or payment data, ask for the SOC 2 report and BAA terms; some vendors self-attest HIPAA.
- Testing and monitoring. Look for simulated test calls, transcripts and analytics so failures can be found before customers find them.
Recommended by situation
No-code builder on its own telephony
Synthflow
Synthflow gives operations staff a visual builder, runs its own telephony and connects to SIP trunks, PBXs and Twilio, with US or EU workspaces.
Trade-off: Pricing is scoped by volume and requirements rather than published, and its trust centre lists HIPAA as self-attested.
Chat and voice from one builder
Voiceflow
Voiceflow builds support agents for web chat, phone and SMS with deterministic workflows plus open-ended playbooks, and hands chat to helpdesks such as Zendesk.
Trade-off: Positioned as an enterprise platform; voice is one channel among several rather than its sole focus.
Voice quality and many languages
ElevenLabs Agents
ElevenLabs Agents pairs a visual builder with its own voice models, connects to phones through Twilio or SIP, and adds SDKs and batch outbound calling.
Trade-off: Language counts differ between its docs and marketing and depend on the voice model you pick.
Developer platform with published per-minute rates
Retell AI
Retell AI combines an agent builder with APIs and SDKs, usage-based per-minute pricing and a self-serve BAA, with free starting credits.
Trade-off: Your all-in rate depends on the model, voice and telephony you choose.
Maximum component control
Vapi
Vapi lets developers choose every component and bring their own models, paying provider costs plus a Vapi per-minute hosting fee.
Trade-off: Requires engineering effort; cost estimates in its docs are not quotes.
Self-hosted enterprise stack
Bland
Bland builds calls as “pathways” and runs its own speech and model stack, with on-prem and VPC options on its enterprise tier.
Trade-off: Aimed at enterprises; compliance documentation is shared under NDA during procurement.
Capability matrix
| Product | Type | Phone | SMS | Chat | Handoff | Languages | Billing | ||
|---|---|---|---|---|---|---|---|---|---|
| Synthflow | Platform | ● | – | – | – | – | Transfers calls | Not stated on pages checked | Quote-based |
| Retell AI | Platform | ● | – | – | – | – | Transfers calls | Depends on the voice and model chosen | Per minute |
| Vapi | Platform | ● | – | – | – | – | Transfers calls | Depends on the providers chosen | Per minute |
| Bland | Platform | ● | ● | – | – | – | Transfers calls | Not stated on pages checked | Per minute |
| ElevenLabs Agents | Platform | ● | ● | ● | ● | ● | Transfers calls | Dozens of languages; count depends on the voice model (docs and marketing differ) | Usage-based |
| Voiceflow | Platform | ● | ● | ● | – | – | Escalates to your helpdesk | Not stated on pages checked | Quote-based |
● = channel documented by the vendor; – = not documented in the sources we checked, which is not proof it is missing. Compliance and integration claims below are the vendor’s own statements.
| Product | What to know | Integrations named | Compliance stated |
|---|---|---|---|
| Synthflow | Visual no-code builder on its own telephony, with SIP and Twilio connections and US or EU workspaces. Pricing is scoped by volume and requirements. | Salesforce, HubSpot, Zendesk, Twilio, SIP / PBX | SOC 2 Type II (vendor); HIPAA with BAA (vendor; trust centre says self-attested) |
| Retell AI | Usage-based per-minute pricing that varies with model, voice and telephony choices; agent builder plus APIs and SDKs; free starting credits. | SIP trunks, CCaaS, CRMs, calendars | SOC 2 Type I and II (vendor); HIPAA self-serve BAA (vendor); GDPR (vendor) |
| Vapi | Developer platform: you pick each component (model, voice, transcription) and pay provider costs plus a Vapi per-minute hosting fee. | Bring-your-own model, voice and telephony providers | Not stated |
| Bland | Conversations built as “pathways” (a graph of steps) on a self-hosted speech and model stack; on-prem and VPC options on the enterprise tier. | APIs, custom tools | SOC 2 Type I and II, HIPAA, PCI DSS (vendor claims; documentation under NDA) |
| ElevenLabs Agents | Visual builder for scripted flows and guardrails plus SDKs and APIs; phone through native Twilio integration or SIP; batch outbound calling. | Twilio, SIP trunking, SDKs, MCP | Not stated |
| Voiceflow | Drag-and-drop builder with deterministic workflows and open-ended playbooks; chat handoff to helpdesks, phone transfer to a number or SIP address. | Zendesk, Genesys, Kustomer, Dixa, UJET | SOC 2 Type 2 (vendor) |
Builder or ready-made receptionist?
If your need is a standard front desk (answer, book, transfer, take messages), a ready-made AI receptionist is faster and cheaper to run. Build your own agent when the call must follow your own process: qualifying leads against your criteria, looking up orders, collecting structured intake, or outbound campaigns.
Plan the first agent
Pick one call type with high volume and clear rules. Write the happy path and the three most common exceptions, decide the transfer rule for everything else, and run test calls with real recordings before you switch on live traffic.
Sources
| Source | Used for | Checked |
|---|---|---|
| Synthflow | Synthflow: platform, compliance | |
| Retell AI | Retell AI: platform, pricing range | |
| Vapi | Vapi: bring your own models, hosting fee | |
| Bland | Bland: pathways | |
| ElevenLabs | ElevenLabs Agents: platform, telephony, languages | |
| Voiceflow | Voiceflow: platform | |
| Synthflow | Synthflow — platform, compliance | |
| Synthflow | Synthflow — telephony | |
| Retell AI | Retell AI — platform, pricing range | |
| Retell AI | Retell AI — pricing components, compliance | |
| Vapi | Vapi — bring your own models, hosting fee | |
| Vapi | Vapi — plans | |
| Bland | Bland — pathways | |
| Bland | Bland — self-hosted stack, compliance | |
| ElevenLabs | ElevenLabs Agents — platform, telephony, languages | |
| ElevenLabs | ElevenLabs Agents — channels | |
| Voiceflow | Voiceflow — platform | |
| Voiceflow | Voiceflow — channels, handoff, security |
Other jobs in this cluster
- AI contact center software: platforms that put AI agents in your queue
- AI customer support agents for chat and email: six options compared
- AI lead-capture chatbots: qualify and book visitors before they leave
- AI receptionist software: six options for answering your business line
- AI vs human answering services: which one should pick up your calls?