An AI sales agent is software that does part of a salesperson's job. Three tools go by the name: an AI SDR cold-contacts people who haven't asked to hear from you, an AI voice agent is phone technology you build on, and an AI sales rep for inbound leads calls your leads within seconds during your team's call hours and hands them to a rep.
If your leads come from web forms, Zillow or Angi, only the third one is built for your problem.
Is an AI SDR the same as an AI sales agent?
Not quite. "AI sales agent" is the umbrella, and the vendors under it don't agree on what it means.
- Artisan, which sells an AI BDR called Ava, defines an AI sales agent as software that automates "the outbound sales process, including prospecting, lead qualification, outreach, follow-ups, and CRM updates."
- Salesforce describes the human SDR job as "a mix of inbound and outbound presales work."
- 11x, known for its outbound AI SDR, now also sells "phone agents" that "call back form-fills while intent is high."
Some vendors call their inbound tool an AI SDR and their outbound tool an AI BDR. Others don't split them at all. So skip the label and ask three questions:
- Who starts the conversation? Your team, working a list, or your lead, by filling out your form?
- What does your rep get at the end? A meeting on the calendar, or a live lead on the phone?
- Who builds the call flow? You, on a platform, or does it come built for a sales team?
What is an AI SDR?
A human SDR, or sales development representative, does the work before a deal. Salesforce lists it as everything "from gathering prospect data and educating prospects to qualifying leads and booking meetings," with outreach "usually via cold calls and emails." The goal is a booked meeting, with the closing rep briefed before it.
An AI SDR does the same job on cold prospects. Here's how the vendors describe theirs:
- Artisan says Ava "sources leads, writes personalized emails, handles replies, and books meetings on your reps' calendars," working from "250M+ verified B2B contacts across 200+ countries." Its FAQ says Ava doesn't place calls. It builds a list of qualified prospects for your reps to dial.
- AiSDR "finds people in real time across the entire web with problems you can solve," then reaches out to drive "qualified meetings that show up."
- HubSpot's prospecting agent costs 100 credits per lead it researches and plans outreach for.
What your rep gets is a meeting with someone who replied. That's a different job from reaching the person who filled out your form a minute ago, and it isn't one Callingly does: we don't prospect cold lists.
What is an AI voice agent?
An AI voice agent is software that holds a phone conversation. It listens, decides what to say and answers in a synthetic voice, on support calls as well as sales. It's a technology more than a job. On a platform like Retell, you pick the model, the voice and the phone line, and pay $0.07 to $0.31 a minute depending on those picks, plus $2 a month per number. The rest of a sales call flow is yours to build: the calling hours, the retries and follow-up texts, and picking which rep gets the lead. Our Retell AI alternatives guide goes through each piece.
What does an AI sales rep for inbound leads do?
It calls every new lead within seconds during your team's call hours, qualifies them on the phone and warm-transfers them to your team to close. That's what Callingly does. The leads are your own: people who filled out your form, or came in from Zillow, Angi or your CRM.
When a new lead lands in Callingly:
- The AI Agent calls, and can text in the same sequence. Calls and texts to US and Canadian leads go out only between 8 AM and 9 PM in the lead's time zone, which Callingly reads from their phone number by default.
- If they don't pick up, it keeps calling and texting on the follow-up sequence you set.
- When they answer, it asks your qualifying questions.
- It rings the available reps in your first priority group at the same time, up to a set limit. If a rep takes transfers on their phone with call screening on, they hear the lead's name, where the lead came from and the most useful thing the lead said, before they accept.
- The lead connects once the rep accepts. If nobody's free, the AI offers a callback at a time the lead picks.
We cover the handoff step by step in what a warm transfer is and how AI does it.
Speed is the whole point. In the 2007 Lead Response Management study of over 15,000 leads, the odds of contacting a lead were 100 times higher when the call came within 5 minutes than after 30 minutes, and the odds of qualifying them were 21 times higher.
How do the three compare side by side?
| AI SDR | AI voice agent platform | AI sales rep for inbound leads (Callingly) | |
|---|---|---|---|
| Who starts the conversation | Your team, from a list of people who haven't asked | Whatever you build: inbound or outbound calls | Your lead, by filling out your form or arriving from a lead source |
| Usual channel | Email and LinkedIn; some add phone | Phone | Phone, with texts in the same sequence |
| How fast | When the prospect replies | As fast as the trigger you build | Within seconds of the lead landing, during your team's call hours |
| What your rep gets | A meeting on the calendar | Whatever handoff you build | The live lead on the line, or a callback the lead asked for |
| How it's priced | HubSpot's prospecting agent: 100 credits per lead | Retell: $0.07 to $0.31 a minute, plus $2 a month per number | From $100 a month in usage credit; $0.50 per AI call on Starter |
| Built for | New pipeline from cold prospects | Teams building their own call flows | Sales teams with inbound web leads |
What about AI SDRs that now answer inbound leads?
The big vendors have moved into inbound. 11x's voice agent starts at $5,333 a month on the Growth plan, billed annually, for 2,000 calls a month, and works alongside Alice, its AI SDR. Salesforce's Agentforce answers inbound leads too: at Agibank, an SDR agent replies to WhatsApp campaign clicks, qualifies the lead and hands the conversation to a rep.
Your lead starts the conversation with both, so the first question won't sort them. Ask these instead. Does it reach your lead by phone, or by chat? Does your rep get the live call, or a chat history? And what happens when nobody on your team is free?
Callingly's answers: phone first, a live warm transfer, and a callback at the lead's chosen time when nobody can take it. The same 2,000 AI calls a month on our Scale plan, also billed annually, come to $650 a month: $600 for $750 of usage credit, plus $0.40 each for the 125 calls the credit doesn't cover. Plans start at $100 a month, with a 14-day free trial and no credit card.
Which one does a team with web leads need?
If you buy or generate web leads in real estate, mortgage, insurance, auto or home services, you already have the people. Your problem is reaching the ones who just asked, while they're still thinking about it. With Callingly your reps stop dialing leads who never pick up: their phone rings when a lead is on the line and has answered your questions. It connects to 1,000+ apps natively or through Zapier, so it works with the CRM and lead sources you already have.
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