Warming up
Transactional email API
443 UK software, SaaS and IT companies name London on their website and publish an email address, as of September 29, 2026. EC1 is the busiest postcode district among those that publish one, and 50% of those that state a founding year started in 2015 or later.
Searching is free. You only spend allowance when you export.
213 of the 443 publish a postcode. Among them, EC1 leads with 34. Districts with fewer than five companies are left out.
| EC1 | 34 (16%) |
|---|---|
| WC2 | 21 (10%) |
| W1 | 18 (8%) |
| N1 | 12 (6%) |
| EC2 | 10 (5%) |
| E1 | 7 (3%) |
| SE1 | 7 (3%) |
| WC1 | 7 (3%) |
| E14 | 5 (2%) |
| SW19 | 5 (2%) |
| EC4 | 5 (2%) |
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.
| Microsoft 365 | 115 (26%) |
|---|---|
| Google Workspace | 114 (26%) |
| Self-hosted | 46 (10%) |
| Hostinger | 17 (4%) |
| Other or unknown | 151 (34%) |
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.
104 of them (23%) state a founding year on their site. This is how those split.
| Before 1980 | 0 (0%) |
|---|---|
| 1980 to 1999 | 10 (10%) |
| 2000 to 2009 | 25 (24%) |
| 2010 to 2014 | 17 (16%) |
| 2015 to 2019 | 27 (26%) |
| 2020 or later | 25 (24%) |
What we have learned about emailing software, SaaS and IT companies. The numbers above tell you how many there are; this is how to get a reply.
Software buyers expect a self-serve path and a clear price. Put the price or the free tier in the email, and show one concrete integration or metric instead of a list of features.
Hi [first name], saw [company] just launched [feature]. When teams at your stage start outbound, the first thing that breaks is usually deliverability on the new domain. Happy to share what the first 30 days should look like if useful.
Replace the bracketed parts per company. In a Warmerly campaign they fill from the lead's own fields.
Tuesday to Thursday. Many teams run sprint planning on Monday and release on Friday.
443 UK software, SaaS and IT companies in Warmerly's database name London on their website and publish an email address, counted on September 29, 2026. A company is matched when its site text mentions London, the same way a city search works in the lead finder, so a firm based elsewhere with a London office is included.
Microsoft 365 runs email for 26% of them, followed by Google Workspace at 26%. 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.
By full-text search over each company's own website text, the same match the lead finder uses when you type London into the city filter. It is broader than a registered address: 213 of these companies publish a postcode, which is where the district breakdown on this page comes from.
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.
