AI Voice Agents: Which No-Code Builders Answer the Phone
By Riley Park · Last verified: October 2026
Who this guide is for
This guide is for a business that wants an AI agent on a phone line: answering inbound calls, booking appointments, qualifying leads or placing outbound calls. It covers the seven no-code AI agent builders DDR has reviewed, and the five voice specialists buyers most often compare them with. One thing to know up front: a DDR Score rates a whole platform, not its phone features, so this page shows what each product can do on a call instead of its score.
The short version. Two of the seven builders treat the phone as a real channel today: Voiceflow (inbound and outbound) and Chatbase (inbound). Botpress lists voice on its Enterprise plan only. Dify can be wired to a phone line with developer work. MindStudio and Gumloop do not take phone calls, and Lindy no longer offers the phone agents it used to. If the phone is your main channel rather than one of several, the specialists are built for that job.
Answering a phone is a harder job for an AI agent than answering a chat window. Four things separate a usable phone agent from a demo.
| Product | Phone calls | Inbound | Outbound | How voice is charged | What you need |
|---|---|---|---|---|---|
| Dify | Developer build | With code | With code | Your Dify plan, plus Twilio and speech fees | A server running Twilio's ConversationRelay sample |
| Botpress | Enterprise only | Not documented | Not documented | Enterprise pricing (custom) | Enterprise plan |
| MindStudio | Not offered | No | No | – | – |
| Voiceflow | Native | Yes | Yes | Credits per minute; business pricing on request | A Voiceflow-provisioned US or Canadian number, or Twilio, Vonage or Telnyx |
| Chatbase | Native, inbound | Yes | Not documented for calls | 6 message credits a minute, plus the model's credits per reply | Standard plan ($150/mo) or higher, and a Twilio number or SIP trunk |
| Lindy | No longer offered | No | No | – | – |
| Gumloop | In the browser only | No | No | About 10 credits a minute (about $0.05) | – |
Dify: Dify has no phone channel of its own. Twilio publishes a tutorial and sample code that connects a Dify agent to calls.
Botpress: Botpress's pricing page lists a voice channel on the Enterprise plan only. We could not confirm how it connects to phone lines, so we describe nothing further until we can.
MindStudio: We found no phone-call channel in MindStudio's documentation. It can send text messages through a Send SMS block.
Voiceflow: Phone numbers also handle inbound and outbound SMS. Call forward and live-agent handoff steps, call recording, and routing a number to a draft version for testing.
Chatbase: The same agent answers chat, email and phone, with the same knowledge and actions. Calls cap at 15 minutes by default, and recordings are optional.
Lindy: Lindy's current documentation and pricing describe a Slack-based AI teammate. Its former phone documentation now redirects elsewhere, and no phone calling is listed.
Gumloop: Talk Mode lets you call your own Gumloop agent from its chat in the browser and talk instead of typing. There are no phone numbers, so customers cannot call it.
Which One Fits Your Phone Line
You already run a chat agent and want it on the phone
Short answer: Chatbase or Voiceflow. Both let the agent you built for chat answer calls with the same knowledge and actions, so you maintain one agent, not two.
Voice, telephony and outbound campaigns are listed from the Standard plan up. Connect a Twilio account or a SIP trunk and assign a number to the agent.
Standard is $150/mo. Voice uses 6 message credits a minute plus model credits. Verified on Chatbase, Oct 8, 2026.
The broadest phone support of the seven: inbound and outbound calls and SMS, numbers from Voiceflow or from Twilio, Vonage or Telnyx, and call forward and live-agent handoff steps.
Business pricing is on request; agencies get a free trial. Verified on Voiceflow, Oct 8, 2026.
Phone is your main channel, or you need outbound calls at volume
Short answer: start with a voice specialist. Retell AI, Bland and Vapi are priced and built around the call itself, with batch or campaign calling, call transfer and high concurrency. Synthflow sells the same job as an enterprise rollout.
Pay as you go with no subscription, 20 concurrent calls included, and batch calling for campaigns.
$0.07 to $0.31 a minute for voice agents, $10 in free credits, numbers $2/mo. Verified on Retell AI, Oct 8, 2026.
One per-minute rate that already includes the model, speech recognition and the voice.
Start: $0.14/min, 100 calls a day, 10 concurrent. Build: $299/mo at $0.12/min, 2,000 calls a day. Verified on Bland, Oct 8, 2026.
Sold as a scoped enterprise rollout with implementation, telephony setup and launch support.
Enterprise contracts start at $30,000 a year. Verified on Synthflow, Oct 8, 2026.
You want a predictable monthly bill
Short answer: ElevenLabs Agents, which sells plans with included call minutes, or Bland, whose per-minute rate already covers the model. Usage-priced platforms are cheaper to start but harder to forecast.
Monthly plans with a set number of call minutes, then a flat rate per extra minute.
Free: 15 min. Creator: $22/mo, 275 min. Pro: $99/mo, 1,238 min. Extra minutes $0.08; model and phone line billed on top. Verified on ElevenLabs, Oct 8, 2026.
No token charges and no separate model or speech fees, so the bill tracks call minutes.
$0.14/min on Start, with telephony billed separately. Verified on Bland, Oct 8, 2026.
You have developers and want to control every part of the stack
Short answer: Vapi, or Retell AI. Both let you choose the model, speech recognition, voice and carrier separately and pass provider costs through, which suits a team that wants to tune cost against speed.
A developer platform that bills its own hosting fee and passes model, speech and voice costs through at cost.
$0.05/min hosting, $5 in free credits, 4 concurrent calls and one number without a package; Core $29/mo. HIPAA add-on $2,000/mo. Verified on Vapi, Oct 8, 2026.
Per-component pricing you can see line by line: the voice engine, each model, each voice, telephony and add-ons such as PII removal.
Voice engine $0.055/min, Retell voices $0.015/min, telephony $0.015/min on Retell's numbers. Verified on Retell AI, Oct 8, 2026.
The Insider's Take
The useful question is not which product is best at voice. It is whether the phone is one channel among several or the job itself. Chatbase and Voiceflow treat the phone as one more place the same agent works, which is exactly right if you already run support in chat and want one agent to maintain. The specialists are built the other way around: everything about their pricing, concurrency and tooling assumes the call is the product. Choosing the wrong side of that line is the expensive mistake, in either direction.
Related
Where a product has a full DDR review, that review is the place for DDR's assessment; a DDR Score rates the whole platform, not one feature. Facts about products not yet reviewed by DDR are limited to what we verified on the vendor's own pages on the date shown. Guides carry no sponsorship placements. Paid relationships never influence scores or rankings.