Warming up
Transactional email API
5,836 marketing agencies in the UK publish an email address on their own website, as of September 29, 2026. 14% name London on their website, more than any other UK city, and WordPress runs on 67% of their websites.
Searching is free. You only spend allowance when you export.
Counted by the city each company's own website names. London leads with 803; a company that names two cities counts in both.
| London | 803 (14%) |
|---|---|
| Manchester | 161 (3%) |
| Leeds | 124 (2%) |
| Birmingham | 74 (1%) |
| Bristol | 73 (1%) |
| Glasgow | 63 (1%) |
| Edinburgh | 55 (under 1%) |
| Sheffield | 55 (under 1%) |
| Newcastle | 52 (under 1%) |
| Liverpool | 45 (under 1%) |
Of the 1,067 that print a Companies House number, 97% are registered in England and Wales, 3% are registered in Scotland and under 1% are registered in Northern Ireland.
Every company here publishes an email address. These are the other routes and signals their websites carry.
A second route for when email goes unanswered.
Growing firms buy more. A useful first filter.
Who hosts their email decides which spam filter reads your message. What their site is built on says what else they already pay for.
| Google Workspace | 1,984 (34%) |
|---|---|
| Microsoft 365 | 1,194 (20%) |
| Self-hosted | 586 (10%) |
| IONOS | 145 (2%) |
| Other or unknown | 1,927 (33%) |
Read from each domain's public MX record. If most of your list is on one provider, warm up a mailbox on that provider first. Filter by provider in the lead finder.
Share of these companies whose homepage loads each technology. Google Analytics is left out because nearly everyone runs it.
937 of them (16%) state a founding year on their site. This is how those split.
| Before 1980 | 33 (4%) |
|---|---|
| 1980 to 1999 | 150 (16%) |
| 2000 to 2009 | 261 (28%) |
| 2010 to 2014 | 206 (22%) |
| 2015 to 2019 | 192 (20%) |
| 2020 or later | 95 (10%) |
Only 122 (2%) say how many people they employ, so read this as a shape, not a census.
| Solo | 17 (14%) |
|---|---|
| 2–10 | 58 (48%) |
| 11–50 | 28 (23%) |
| 51–200 | 7 (6%) |
| 201–500 | 3 (2%) |
| 1,001–5,000 | 6 (5%) |
| 10,000+ | 3 (2%) |
Some sites tell search engines exactly what kind of business they are, in structured data. These are the types they declare most often, which shows the mix inside this category.
| Professional service | 313 (5%) |
|---|---|
| Marketing agency | 14 (under 1%) |
| Advertising agency | 13 (under 1%) |
What we have learned about emailing marketing agencies. The numbers above tell you how many there are; this is how to get a reply.
Agencies are pitched constantly and spot a template in one line. What works is something they can resell or that makes a client retainer easier to defend: a white-label deliverable, a faster report, a new service line they can price.
Hi [first name], noticed [agency] runs paid social for a lot of local service brands. Most agencies we talk to lose margin on reporting. We built a way to turn that into a line item clients pay for. Worth a 10 minute look?
Replace the bracketed parts per company. In a Warmerly campaign they fill from the lead's own fields.
Tuesday to Thursday mornings. Monday is client status calls and Friday afternoon is reporting, so both bury cold email.
Warmerly's lead database holds 5,836 marketing agencies in the UK that publish an email address on their own website, counted on September 29, 2026. That is not every such business in the country. It is the ones whose site we crawled and that list a way to contact them by email, which is the number that matters for outreach.
Google Workspace runs email for 34% of them, followed by Microsoft 365 at 20%. It is read from each domain's public MX records. It matters for cold email because Google and Microsoft filter differently, so a sending mailbox on the same provider as most of your list is worth warming up first.
London, named by 803 of them, then Manchester (161) and Leeds (124). The count is companies whose website names the city, so one business can appear under more than one.
Yes. Searching the database in Warmerly is free, and you see the same count as this page before spending anything. Exporting or adding companies to a campaign uses your plan's monthly lead allowance. Every result is a business contact route the company publishes itself, and any company that has asked to be removed is excluded. This page shows totals only, never individual companies.
Filter them by size, founding year, technology and hiring, see what each record holds, then send from warmed-up mailboxes in the same tool.
