If you looked at Retell AI to call your new web leads, you were about to build a speed-to-lead system out of parts. The alternative is a tool that already does the job: Callingly calls each new lead within seconds during your team's call hours, follows up by call and text, asks your qualifying questions and warm-transfers the live lead to an available rep.
Retell is a good set of parts, and the voice agent is the part it makes easy. For a sales team, the work is everything around the agent: starting a call the moment a lead lands, keeping calls inside the lead's hours, trying again when nobody picks up, and getting the lead to a rep who can take it right now. That's the work we compare here.
Best Retell AI alternatives for calling inbound web leads
- Callingly. For B2C sales teams in real estate, mortgage, insurance, auto and home services. Nothing to build. From $100 a month, with a 14-day free trial and no credit card.
- Vapi. A developer platform for teams that want to assemble their own voice agent.
- Bland AI. An enterprise voice AI platform for high-volume, regulated and complex phone work.
- Synthflow. Voice AI for enterprises, with contracts starting at $30,000 a year.
Does Retell AI require a developer or coding?
Not for the agent itself. Retell's docs say you can "build entirely from the dashboard with no code, or go fully programmatic with the API, SDKs, and an MCP server." Writing the prompt, picking a voice and adding a transfer all happen in the dashboard.
The coding shows up around the agent. Here's the job a sales team needs done, one step at a time, with what Retell's docs describe for each step and what Callingly does out of the box.
| Step | Retell AI (from its docs) | Callingly |
|---|---|---|
| A new lead lands in your CRM | HubSpot and Zoho CRM workflows can start a call through Retell's app. For other CRMs, your own code or an automation tool calls Retell's Create Phone Call API. | Native connections to Follow Up Boss, HubSpot, Salesforce, Pipedrive, CINC, Lofty, GoHighLevel, Zoho and more, plus Zapier, webhooks, email and an API. |
| Call within seconds, at the right time | A calling window is described for batch calls, set in one time zone (America/Los_Angeles unless you choose another). When to place a single call is up to your system. | Calls within seconds in the hours your team takes calls, and, for US and Canadian leads, only between 8 AM and 9 PM in the lead's own time zone, read from their phone number by default. |
| Nobody answers | A retry sequence isn't described in Retell's docs. | Your call and text sequence keeps trying on the schedule you set. |
| Text the lead | SMS on Retell's Twilio numbers or your own Twilio number after A2P carrier registration (about 2 to 3 weeks, US numbers only, no toll-free). | A text when the lead arrives, after a missed call or right before a call. US and Canadian numbers need carrier registration first, 7 to 14 business days. |
| Ask your qualifying questions | Written into the agent's prompt or conversation flow. | Set your questions, script and voice in the AI Agent. |
| Hand the lead to a rep who's free | Warm transfer to a phone number, a SIP address (an internet phone address) or a number your system fills in for each call. Picking which rep is free isn't described on the transfer page. | Rings the available reps in your first priority group at the same time, up to a set limit, and connects the one who accepts. |
| Nobody can take it | Its AI-screened transfer can cancel and hand the caller back to the agent. What happens after that is yours to build. | The AI offers the lead a callback at a time they pick. If a transfer fails, Callingly calls your team to get a rep on the line, then tries the lead again. |
| Record it and log it | HubSpot gets the call summary, extracted answers, recording and transcript. Salesforce, Dynamics 365, GoHighLevel and Zoho get a scheduled contact sync. | Every AI call keeps its recording and a transcript labelled by speaker. Your CRM gets the rep's call with its recording link. |
If your team runs on HubSpot, Retell's app covers the first step without code: Retell lists "call leads immediately after they submit a form" as a use case. The rest of the table is still yours to build: the calling hours, the retries and follow-up texts, and picking the rep. Those are the parts that decide whether a lead talks to a person or gets a voicemail.
Retell AI warm transfer vs handing the lead to whichever rep is free
Retell's transfer tool is well built. It has three modes: a cold transfer, where the agent drops off; a warm transfer, where the agent stays on and can play a private message to whoever answers or make a three-way introduction; and an AI-screened warm transfer, where a second AI agent talks to the person who picks up and then connects the caller or cancels.
For a sales team, the part that matters is who gets called. Retell transfers to the destination you hand it, so if you want a lead to reach whichever of your ten reps is free this minute, your system has to work that out and fill in the number before the transfer starts.
Callingly works the other way: it starts from your reps. When the AI Agent has a qualified lead on the line, it rings the reps who are available, and the lead owner first if your routing says so and they're free. Reps who take the call on a phone line, rather than in the Callingly app, can hear a short briefing before the lead joins: the lead's name, where they came from and the most useful thing they said. That's the warm transfer built around a sales floor rather than a single number.
Retell AI CRM integrations and lead qualification
Outside HubSpot, Retell syncs contacts every 5 minutes with Salesforce, Dynamics 365, GoHighLevel and Zoho (as of August 2026) and, by default, updates records that already exist rather than creating new ones. Follow Up Boss isn't listed in Retell's docs.
That gap matters most to real estate teams, since Follow Up Boss is where a lot of them work their leads. Callingly connects to Follow Up Boss with a Connect button and calls each new person whose lead source matches your routing rules. CINC, Lofty, HubSpot and Salesforce connect natively too (see our integrations page), and the AI Agent asks your questions on every call.
Callingly vs Retell AI pricing
Retell prices voice agents at $0.07 to $0.31 a minute, built from parts: the language model, Retell's voice infrastructure ($0.055 a minute), text-to-speech and phone minutes. Retell's own calculator example comes to $0.11 a minute when you bring your own phone carrier. Retell's phone numbers are $2 a month, and its texting is $20 a month plus $0.01 a message.
So a 3-minute call costs $0.21 to $0.93 in Retell usage. That's before phone numbers, texting, and the cost of building and running the steps in the table above. Call length varies with every script, so we can't give you one Retell total.
Callingly bills per AI call, not per minute. An AI call is billed once when it reaches the lead or their voicemail, and calls that ring out or hit a busy line aren't billed. On accounts that signed up directly since September 26, 2026, talk time is included, and that covers the transfer to your rep.
Here's a worked example. Say your team gets 300 new web leads a month and the AI calls each one about twice. That's an assumption: some answer the first call, some take three. At most that's 600 AI calls. On the Growth plan, $250 a month buys $250 of usage at $0.45 per AI call, so 600 calls comes to $270, about 90 cents a lead. On Starter, $100 a month with $100 of usage at $0.50 per call, the same month is $300. Phone numbers are $5 a month each. Full rates are on the pricing page.
Other Retell AI alternatives: Vapi, Bland AI and Synthflow
These three often come up next to Retell. Like Retell, they're platforms you build a voice agent on, so the table above applies to each of them. If you're comparing AI ISAs for real estate rather than voice platforms, our Structurely alternatives guide covers that list.
Vapi
Vapi charges $0.05 a minute for Vapi hosting, then bills speech-to-text, the language model and the voice on top at the providers' own rates, with phone minutes billed by your carrier. Its paid Success Packages start at $29 a month. Transfers are blind by default (the same as a cold transfer), with warm transfers using a message or a summary as options. Its integrations page has guides for Make, n8n, GoHighLevel, Slack and Google tools, and none for HubSpot or Salesforce.
Bland AI
Bland's Start plan is $0.14 a minute with no platform fee and a cap of 100 calls a day. The Build plan is $0.12 a minute plus $299 a month. Bland's docs say warm transfer "requires an enterprise account," and transfer minutes are billed separately.
Synthflow
Synthflow's pricing page lists Enterprise contracts starting at $30,000 a year. Its docs note that each warm transfer starts a new outbound call that counts against the account's limit on calls started per second, which can slow new outbound campaign calls when transfers are frequent.
Frequently asked questions
What are some free alternatives to Retell AI?
None of these platforms makes live calling free. Vapi lets you start at $0 on prepaid usage, Bland's Start plan has no platform fee but bills per minute, and Retell gives new accounts $10 in free credits. Callingly has a 14-day free trial with no credit card, so you can run it on real leads before you pay.
How hard is it to switch from Retell AI to Callingly?
There's no importer for Retell agents. Moving over means connecting your CRM or lead source (natively, through Zapier or with a webhook), writing your qualifying questions into the AI Agent, and setting your call hours and who gets transfers. Your prompt is a good starting point for the questions.