AI SDR: what an AI sales agent handles, what it costs, and where it stops

What is an AI SDR?

An AI SDR is software that runs a sequence of sales development steps on its own, then reports back to a person. What separates it from a plain automated form is that it picks the order of its actions based on what it finds, and it leaves behind a record you can act on.

The label covers two fairly different products. Relevance AI is built for businesses deploying and supervising teams of agents, with SSO, roles and audit logs in its single plan. Retell AI targets teams that want to launch AI phone agents on a per-minute basis, without an annual contract. Our documentary review scores the first 2.8 out of 5 and the second 3.6 out of 5. Most of that gap comes from price and from how readable each offer is.

Which parts of the sales job can it actually take over?

Four blocks come up every time: researching a prospect, sending the first messages, asking a handful of qualification questions, and placing or taking a call. In practice, those blocks do not live inside the same product.

The call is the most mature piece, because it is measurable by the minute. Retell AI gives full platform access with no subscription and includes 20 concurrent calls from the start. Relevance AI lists calling and meeting agents, evaluations and access controls: we rate it 4 out of 5 on features, and 3 out of 5 on ease of setup.

Prospect research and written follow-up, on the other hand, almost always rest on connections between tools you already run. That is automation territory, where n8n bills per complete workflow run rather than per step (Starter at 20 EUR per month billed yearly) and Make starts at $9 per month billed yearly for 10,000 credits. If you are starting from nothing, our guide to building an AI agent with n8n or Make walks through that chain.

What does an AI SDR cost?

The two pricing models are not comparable, and for a small business that is the deciding factor.

At Retell AI, the $0.07 to $0.31 range comes from stacking parts: language model, voice, telephony. Voice infrastructure alone is listed at $0.055 per minute. That is transparent, but the final bill stays hard to estimate up front, which we count among its weak points. The component-by-component breakdown sits in our piece on what a minute of calls really costs.

Why does Relevance AI show no price?

Because its public pricing page now presents a single Enterprise plan, described as custom actions and vendor credits with unlimited agents and tools. No amount is readable on it. Free, Pro and Team tiers still circulate on another page of the site, but nothing establishes that this page is current, so we do not carry those figures over.

In our reading, pricing that disappears is a positioning signal rather than an oversight. A vendor that pulls its self-serve tiers is steering the product toward negotiated annual contracts and longer buying cycles. If you want to test an idea in two weeks, that is a concrete obstacle: you talk to a salesperson before you learn the entry ticket. That is what earns Relevance AI 1 out of 5 on its free offering and 2.5 out of 5 on price. The rest of the detail sits on its tool page.

Where do your prospect records end up?

With Retell AI, in the United States: processing and storage run on AWS, and the documentation states that the vendor does not yet operate services inside the European Union. In exchange, the contractual file is fuller than the price suggests: SOC 2 Type 1 and Type 2, HIPAA, and a DPA including EU standard contractual clauses that can be signed online at no cost. Retention is set agent by agent, from 1 day to 2 years. We score its GDPR column 2.5 out of 5.

For Relevance AI, the data region could not be verified, and we assume no contractual commitment on that point: the same 2.5 out of 5, for a different reason. Either way, the question is worth raising before you sign, because an AI SDR handles contact details of identifiable people by nature and, on the phone, recordings of conversations.

What should you not hand to an AI SDR?

Three things, and they have more to do with commercial risk than with technology.

Negotiation first. An agent that improvises a discount or a delivery date commits you in front of a customer. Both vendors sell supervision (roles, audit logs and evaluations at Relevance AI), not decision-making autonomy.

Your strategic accounts next. A badly calibrated first touch on a large prospect is hard to undo. Keep the agent at the top of the funnel, where volume justifies automation and a mistake is cheap.

Unwatched volume last. With per-minute billing, a loosely scoped scenario consumes with no visible ceiling. Worth remembering too: outside Enterprise, Retell AI support is limited to community and email, so nobody is going to call you about a runaway script. Set the guardrails yourself, and decide who reads the transcripts. On the CRM side, our comparison of the AI features in HubSpot, Pipedrive and Zoho CRM shows what the software you already pay for automates without a dedicated agent.

Which one fits your situation?

If the need is phone work and you want an answer within days, Retell AI is the more accessible entry point of the two: $10 in credits at sign-up, no subscription, $0.07 to $0.31 per minute, and 20 concurrent calls included. It works as a bench to price real usage before you commit a budget. Main reservation: the data leaves for the United States.

If you run several agents and several teams, and governance counts as much as price, Relevance AI speaks your language with SSO, roles and audit logs. Expect a quote, with no public figure to plan around beforehand.

If your priorities are prospect research and written follow-up rather than calls, start with automation before the agent. A base at $9 per month with Make, or 20 EUR per month with n8n billed yearly, covers a good share of the need, and it stays in place the day you put an agent on top of it.