Best cold email agencies for ad tech

The ten at a glance

Four of the ten publish or have a credibly reported entry price. Every figure was checked against the agency's own site in October 2026 where it publishes one, and marked as reported where the number comes from third-party coverage rather than the agency itself.

Ad tech is two markets, not one

Almost every agency on this page will treat ad tech as a slice of B2B SaaS. It is not, and the difference decides whether a campaign works.

Ad tech splits into a supply side and a demand side, and they are different companies with different economics and opposite anxieties.

Supply side owns inventory: publishers, screen networks, venue operators, anyone with attention to sell. Their question is how to monetise what they already have without degrading the experience. They care about fill rate, CPM floors and who they are letting onto their property.

Demand side buys inventory: advertisers, agencies, DSP users. Their question is how to reach an audience at a price that works. They care about reach, measurement, fraud and attribution.

A campaign written to "ad tech companies" speaks to neither. The words that make a publisher lean in are the words that make an advertiser stop reading, because one is being offered revenue and the other is being offered cost.

Then there is the layer underneath both: the platform companies selling the rails, from DSPs and SSPs to measurement, identity and content management. Those sell to supply and demand simultaneously, which means two campaigns rather than one that averages them.

The practical consequence for hiring an agency is narrow and useful. Ask which side of the market a proposed list sits on. If the answer is a company-size filter and an industry label, the campaign has not been designed yet.

The hardest inbox in the dataset

The figures below come from Grow Surely's own dataset of 6,074,430 emails, of which 330,000 were sent in 102 marketing and advertising campaigns, published in full including the rows that are unflattering.

Read the auto-reply row first, because it is the one that is genuinely unusual. At about 71%, marketing and advertising sends more machine replies than any other industry measured, including manufacturing at 67% and SaaS at 69%. Roughly seven of every ten things that land in the reply folder are an autoresponder, a routing notice or an out-of-office.

That matters more than it sounds, because almost every agency reports the raw number. A dashboard showing 1.7% replies in this market represents 0.5% actual humans. An agency that does not separate the two will show a result three times better than the one being delivered, without anyone needing to lie.

The reason is structural rather than cultural. These are desk-based companies with the heaviest tooling stacks in B2B: shared inboxes, routing rules, ticketing, calendar bots, enrichment tools and whatever the marketing team installed last quarter. Every one of those can generate a reply, and none of them is a person.

The volume consequence is simply arithmetic. Ten meetings a month implies something near 42,000 emails at the measured rate, against 35,000 for the all-industry average and 21,000 at the easy end of the dataset. A proposal promising ten meetings from 5,000 sends into this market is not ambitious; it is describing a reply rate eight times the measured average.

You are emailing people who do this for a living

There is a second problem the data cannot show, and in practice it is the bigger one.

In most markets a cold email arrives as a novelty. In ad tech it arrives in front of someone who has read a thousand of them, written a few hundred, and very possibly sells the software used to send them. The audience is not just marketing-literate. It is outbound-literate.

That removes an entire category of tactics from the table. The fake reply thread, the "quick question" subject line, the first name dropped into a sentence it does not belong in, the fabricated compliment about a recent funding round, the pretend referral: this audience built those, tested them, and watched them stop working. Using them here does not fail quietly. It identifies the sender as someone running a template, which costs the reply and the brand at the same time.

What remains is uncomfortable but simple. A specific, checkable observation about that company's inventory, product or market, written like a person who looked, followed by a plain ask. Nothing else survives contact with this audience, which is why ad tech punishes agencies that scale by volume and rewards the ones that scale by segmentation.

It also changes who should be approving the copy. In most verticals an agency can write, send and report. Here the client usually knows the market better than any agency will after a month of research, so the sensible arrangement is the agency owning infrastructure, lists, sending and reporting, and the client owning the angle.

What actually works, with the numbers

The useful thing about a market this hard is that the exceptions are instructive. Here is a published one.

Spotlight sells digital out-of-home advertising on screens inside US zoos: supply side, tiny addressable market, no realistic paid-acquisition route because the buyer pool around each location is too small to support it.

The campaign was built as 36 separate campaigns. Three zoo locations, twelve industries around each, every one with its own list and its own angle, sending a deliberately low 400 emails a day in total.

Twelve times the vertical average, at roughly a tenth of the usual send volume, sustained over a full year rather than a good fortnight. Across 80,300 emails and twelve months the account averaged 6.08% and produced 119 opportunities.

The mechanism is not clever copy. It is that a message aimed at a restaurant within fifteen minutes of one specific zoo can say something true and checkable that a message aimed at "local businesses" cannot. Thirty-six narrow campaigns produce thirty-six true sentences. One broad campaign produces one vague one.

As Spotlight's Head of Sales, Ana Meadow, put it: "We're getting 8 demos every single week and the meetings actually convert."

Worth noting what the account did not do. It did not scale volume: 400 emails a day is a fraction of what a general agency would propose for a target of eight meetings a week. It did not chase a bigger market either, in a vertical where the buyer pool around each location was small enough that paid acquisition made no economic sense. The growth came entirely from splitting one audience into thirty-six, and that is the part that transfers to any ad tech company with a defined set of accounts rather than a category.

The practical test for any agency on this page is therefore how many campaigns they intend to run, not how many emails. An agency proposing one campaign into ad tech is proposing the thing the data says does not work.

The four standards everyone here is judged on

Each agency below is scored on the same four, and the scoring is deliberately boring.

Does it name ad tech at all? Not "technology", not "B2B SaaS". One of the ten does.

Published proof with a name and a number. A company, a figure and a timeframe, rather than a logo wall.

A price anyone can read without a call. Three state one on their own site. Four more can only be priced from third-party reporting, which is better than nothing and worse than a published figure. Three give no number anywhere.

What happens if it does not work. Contract length, notice period, and whether any of the risk sits with the agency rather than all of it with the buyer.

1. Grow Surely

Grow Surely is the only agency on this page that will run the campaign before being paid for it. Seven days, three to five qualified meetings booked against criteria agreed in advance, no card and no contract. In the hardest inbox measured in B2B, that is the cheapest possible way to find out whether a given list replies at all.

It is also the only one of the ten with published ad tech results carrying a company name, a number and a timeframe.

Spotlight, selling digital out-of-home inventory on screens inside US zoos, ran at a 6%+ reply rate against a 0.5% vertical average, booked eight sales calls a week and closed $170K+. Across twelve months that account sent 80,300 emails at 6.08% and produced 119 opportunities, which is a sustained figure over a year rather than a strong opening fortnight.

Pros. The free pilot removes the only decision that carries real risk. The underlying reply-rate data is published in full rather than summarised, including the verticals that perform badly and the auto-reply split that most agencies leave merged. The approach is built around campaign count rather than send volume, which is what the evidence in this vertical supports. Sixteen named case studies, 95% monthly retention against an industry norm closer to 65%, and billing month to month with no minimum term.

Cons. Email only, so an ad tech company that wants conference coverage or a phone team is better served elsewhere on this page. The pilot is aimed at companies over $2M a year in revenue. A public review base of 4 on Clutch, all at 5 stars, against the larger generalists.

2. Whistle

The only agency of the ten that names this market on its own website. Whistle markets outsourced SDR teams specifically for martech and adtech companies, and offers two shapes: a fully managed team, or vetted SDRs hired to sit inside the client's own operation.

The speed claims are unusually specific. Whistle says a managed team can be live in about ten business days, that the hire-an-SDR route books meetings within five days, and that most clients see first meetings two to three weeks after launch. It publishes client outcomes with ROI multiples attached, including $420K in pipeline at 17X for one client and $340K at 8X for another, and says it has worked with over 350 companies.

Pros. Genuine vertical positioning rather than an industry checkbox. Conference lead generation is included, which matters more in ad tech than almost anywhere else given how much of this market's buying still happens at events. Team size scales up and down. Covers inbound MQL follow-up and product-led motions as well as cold outbound.

Cons. No published pricing or contract terms, so neither can be compared before a call. The published case studies carry pipeline and ROI figures but not the timeframes behind them. Marketing is one of eight industries listed, so the specialism is a focus rather than an exclusive practice.

3. Belkins

The most publicly accountable agency in the category, at 4.9 across 230+ Clutch reviews built over 800+ clients since 2017. For an ad tech company that has to defend the choice of vendor internally, that review record is the strongest available answer. Cleverly carries more reviews in raw count, around 1,120, but they sit on Trustpilot rather than Clutch and average 4.5 rather than 4.9.

It runs omnichannel outreach across cold email, LinkedIn and calling, and is reported at $3,000 to $15,000+ a month, though it publishes neither pricing nor minimum term on its own site. There is a longer comparison in Belkins alternatives.

Pros. The largest Clutch review base here by a clear margin, at 230+ against CIENCE's 142 and Martal's 109. Deep operational maturity and a long track record. Multi-channel rather than email alone.

Cons. Ad tech is not named anywhere as a served vertical, and the published case material skews heavily to SaaS and IT. Multi-month minimums are reported as standard, and nothing about pricing or terms is visible before a call.

4. CIENCE Technologies

The research-heavy option. CIENCE runs multi-channel outbound with its own in-house data operation and intent data, and gives clients more visibility into how a list was constructed than most agencies offer. In a market where list quality is the whole game, that is a genuine argument.

Its pricing is reported rather than published, and it is the most itemised on this page: around $1,750 a month for an offshore SDR or $3,500 for a US or EU one, plus roughly $2,000 for a campaign team and a $499 platform fee. Stack those and the real entry point is well above the headline.

Pros. The deepest data and research operation here. Intent signals are more useful in ad tech than in most verticals, because platform switching tends to follow visible triggers. A large review sample, which makes the rating meaningful rather than anecdotal.

Cons. Their public ratings diverge more than anyone else's: 4.2 on Clutch, 3.8 on G2 and 1.7 on Trustpilot. Twelve-month commitments and a setup fee on top of the retainer are the most common complaints. There is a longer comparison in CIENCE alternatives.

5. Callbox

The international operator. Callbox runs email, calling, LinkedIn, chat, webinars and content syndication across more than 50 industries, with real coverage outside North America. Ad tech is unusually global for a B2B category, so a vendor that can run APAC and EMEA properly solves a problem the domestic specialists cannot.

Typical client spend is reported at $20,000 to $40,000 a quarter, roughly $6,600 to $13,300 a month, which places it firmly in the enterprise bracket.

Pros. Genuine multi-region capability, including markets most agencies here cannot service. Webinar and event support, which suits a market that still buys at conferences. Long operating history.

Cons. Ad tech is not named among its listed verticals. Nothing published on pricing. Multi-month commitments are standard and the entry cost excludes most companies below late-stage growth.

6. Martal Group

A fractional sales team rather than a campaign. Martal places experienced reps across email, LinkedIn and phone, operating since 2009 with 4.8 across 109 Clutch reviews. Only Callbox, trading since 2004, and SalesRoads, since 2007, have been at it longer, and only Belkins and CIENCE carry more Clutch reviews.

The shape suits an ad tech company with no sales development function at all, where the need is a working sales motion rather than a channel test. It does not publish pricing. There is a longer comparison in Martal Group alternatives.

Pros. Long, verifiable history and a strong review record. Senior reps rather than junior SDRs. A fractional model that covers more of the funnel than appointment setting alone.

Cons. No published pricing. Positioning leans to SaaS and tech generally rather than ad tech. Public reviews cite limited visibility into sequences and data, which is exactly the thing worth seeing in this vertical.

7. UnboundB2B

The content syndication option, and a different instrument from everything else here. UnboundB2B runs intent-based demand generation, programmatic display, webinars and SDR outreach together, with enterprise technology logos including Dell Technologies, Rapid7, Freshworks and RingCentral.

For ad tech specifically there is a neat fit worth naming: this is a market that already understands and buys programmatic media, so a vendor combining content syndication with outbound is speaking the client's own language rather than explaining a channel.

Pros. Covers demand generation and outbound in one engagement. Genuine enterprise technology experience. Intent data is applied across channels rather than only to a send list.

Cons. Ad tech is not named as a vertical. Content syndication leads are a different and generally colder product than a booked appointment, so the two are not directly comparable on price. No published pricing, and the headline figures are attached to campaigns rather than to a named company and timeframe together.

8. SalesRoads

The onshore phone specialist, operating since 2007 with 4.9 across 69 Clutch reviews and published pricing at $11,950 per four weeks for a dedicated SDR. It is one of only three agencies here that states a real number on its own website.

The phone deserves more consideration in ad tech than the email-first default suggests, for one measurable reason: when about 71% of email replies are machines, a channel with no autoresponder layer stops looking expensive and starts looking like a different denominator. There is a longer comparison in SalesRoads alternatives.

Pros. Published pricing and a long verifiable record. US-based callers. Sidesteps the auto-reply problem entirely rather than managing around it.

Cons. Among the highest entry prices here. Each SDR covers a fixed number of accounts, so the economics need a large deal size. No ad tech proof published, and senior ad tech buyers are among the harder people in B2B to reach by phone.

9. Abstrakt Marketing Group

The largest full-service operation on this page, running outbound appointment setting across phone, email and LinkedIn alongside marketing and creative services. It is the only agency here whose retainer is tied to a stated appointment count: from $5,250 a month for four or more, which works out near $1,310 per appointment.

That structure is worth something in a market this hard, because it converts a vague promise into a number that can be held against an invoice. It also guarantees to keep working at no further charge if the promised appointments are not delivered.

Pros. A retainer attached to a committed appointment count, which almost nobody else offers. A work-until-delivered guarantee. One partner per market. Published case studies with real figures, albeit in other industries.

Cons. The highest implied cost per appointment here. Its own FAQ says most partners begin seeing appointments within 45 to 60 days. Its vertical practices are built around traditional service industries rather than technology, and nothing is published on ad tech.

10. Cleverly

The LinkedIn-first option and the cheapest entry point on this page, reported from $397 a month. LinkedIn carries more weight in ad tech than in most verticals, because this is a market whose professionals genuinely live on the platform, publish on it and are reachable there.

The ceiling is the problem. LinkedIn caps outreach at roughly 400 companies a month regardless of budget, which is nowhere near the volume the measured reply rates in this vertical demand. There is a longer comparison in Cleverly alternatives.

Pros. The lowest cost of entry here by a wide margin. A large open review base on Trustpilot, which samples differently from Clutch and is harder to curate. LinkedIn genuinely suits this audience.

Cons. The volume ceiling is structural and cannot be bought past. No pricing published on its own site, and its pricing page returns a 404 despite dozens of roundups quoting figures. Nothing published on ad tech.

What a meeting actually costs, in emails

Every proposal contains a meeting target. Very few contain the sending volume required to reach it, and in this vertical the gap between the two is wide enough to sink a quarter.

Working from the measured marketing and advertising rates: 0.5% of emails get a human reply, roughly 18% of those replies are positive, and about one positive reply in four becomes a booked meeting. That chain produces approximately 4,200 emails per meeting.

Hold any proposal against that table before signing it. An agency promising twelve meetings a month from a few hundred sends a day is describing a reply rate several times the measured average, and the shortfall will arrive in month three dressed as a market problem.

There are two honest ways out of the arithmetic, and both are better than pretending it does not apply.

Segmentation changes the rate, not the volume. The Spotlight account above reached 6%+ against a 0.5% average, which is twelve times the input this table assumes, by running 36 campaigns instead of one. Narrow enough targeting makes the volume requirement collapse. This is the route that works, and it is work rather than spend.

Another channel changes the denominator. A phone-led or event-led programme is not bound by email reply rates at all, which is the strongest argument for SalesRoads or for Whistle's conference coverage in a market where roughly 71% of email replies are machines.

What does not work is the third option, which is sending more. At these rates, doubling volume into an undifferentiated list doubles the cost and the domain damage while leaving the reply rate exactly where it was.

Five questions to ask on the first call

These produce different answers from different agencies, rather than the same reassurance from all of them.

1. Which side of the market is this list on? Supply or demand. If the answer is an industry label and a headcount range, the campaign has not been designed, and in ad tech that single confusion is the most common reason a programme produces nothing.

2. How many separate campaigns will be running? One is the wrong answer. The published example on this page used 36. Campaign count is the lever that moves reply rate in this vertical, and an agency that plans by send volume alone has not worked out why.

3. What share of the replies you report will be automatic? In marketing and advertising it is about 71%, the highest measured anywhere. An agency that does not separate machines from people will show a number three times better than reality without ever saying anything untrue.

4. Who writes the angle, you or us? This audience spots a template instantly. The arrangement that survives contact is usually the agency owning lists, infrastructure, sending and reporting, with the client owning the claim being made.

5. What happens in month one if nothing lands? Listen for whether the answer involves the agency's money or only its effort. One agency here runs the first week free and one keeps working at no further charge until the promised appointments arrive. The other eight answer this question with optimism.