The most used email delivery services
We track 20 email delivery services. The most used is SendGrid, found at 188,987 companies as of October 2026, ahead of Amazon SES (58,360) and Mailchimp Transactional (56,111).
Email delivery services send the emails an app generates: sign-up confirmations, password resets, receipts and notifications. SendGrid, Amazon SES and Mailgun are the long-standing leaders; Postmark is known for deliverability on transactional mail, and Resend has grown quickly with developers.
Email delivery services ranked by companies using them
“Share” is each tool's part of all 470,817 matches in this category; a company that uses two tools counts for both.
| # | Tool | Companies | Share | Last 30 days | Most popular with |
|---|---|---|---|---|---|
| 1 | 188,987 | 40% | +47−3 | 1,001–5,000 employees (1.6×) | |
| 2 |  Amazon SES | 58,360 | 12% | +34−9 | 1,001–5,000 employees (2.0×) |
| 3 | 56,111 | 12% | +12−2 | 1,001–5,000 employees (1.7×) | |
| 4 | 47,470 | 10% | +55−3 | – | |
| 5 | 25,263 | 5.4% | +119 | 1–10 employees (4.0×) | |
| 6 | 24,122 | 5.1% | +2−2 | 1,001–5,000 employees (1.7×) | |
| 7 | 21,904 | 4.7% | +105−1 | – | |
| 8 | 15,582 | 3.3% | +9−4 | Insurance (3.8×) | |
| 9 | 9,121 | 1.9% | +1−1 | Non-profit Organization Management (2.2×) | |
| 10 | 6,011 | 1.3% | +4 | Non-profit Organization Management (2.2×) | |
| 11 | 4,429 | 0.94% | +96−1 | Construction (2.4×) | |
| 12 | 3,481 | 0.74% | +37 | Software (1.6×) | |
| 13 | 2,392 | 0.51% | +49 | Hospitality (3.6×) | |
| 14 | 2,275 | 0.48% | +37−1 | Construction (2.6×) | |
| 15 | 1,811 | 0.38% | +59 | Staffing and Recruiting (7.3×) | |
| 16 | 938 | 0.20% | +120 | 1–10 employees (3.1×) | |
| 17 | 733 | 0.16% | +27 | Software (2.0×) | |
| 18 | 696 | 0.15% | +16 | Automotive (2.4×) | |
| 19 | 610 | 0.13% | +2 | Publishing (15×) | |
| 20 | 521 | 0.11% | +1 | Financial Services (1.7×) |
“Most popular with” is the industry or company size where the tool is most over-represented compared with all companies we've scanned. Starts and stops compare two scans done the same way.
Who's gaining and losing customers
- ImprovMX: 120 started in the last 30 days
- Resend: 119 started in the last 30 days
- MailChannels: 105 started, 1 stopped in the last 30 days
- SMTP2GO: 96 started, 1 stopped in the last 30 days
- Flowmailer: 59 started in the last 30 days
- Mailgun: 55 started, 3 stopped in the last 30 days
How to compare email delivery services
- Deliverability and separation of transactional from marketing mail.
- Developer experience: API, SDKs and email templates.
- Price per thousand emails at your volume, and dedicated IP options.
- Logs, webhooks and bounce handling.
How we find email delivery services
Sending services must be authorized in DNS, so they show up reliably in SPF includes, DKIM keys and the MX or return-path records of sending subdomains.
Every company on a tool's page links to the record behind the match. DNS is rechecked weekly and websites monthly, so tools a company stops using drop off the list.
Email Delivery FAQ
What are the most popular email delivery services?
As of October 2026, the most popular email delivery services by number of companies using them are SendGrid (188,987 companies), Amazon SES (58,360 companies) and Mailchimp Transactional (56,111 companies), according to runsonwhat. SendGrid alone accounts for 40% of the 470,817 Email Delivery matches runsonwhat has, and the top three together for 64%. 20 email delivery services have at least one confirmed customer.
SendGrid vs Amazon SES: which is more popular?
SendGrid is more popular: 188,987 companies show public evidence of SendGrid, against 58,360 for Amazon SES (3.2× as many), according to runsonwhat (October 2026). Mailchimp Transactional is third with 56,111.
Which email delivery services do small businesses use most?
Among companies with up to 50 employees, the most used email delivery services are SendGrid (85,137 companies), Mailchimp Transactional (23,759 companies) and Mailgun (23,092 companies), according to runsonwhat (October 2026). The counts cover companies with a known headcount; see each tool's page for the full size breakdown.
Which email delivery services do large companies use most?
Among companies with more than 1,000 employees, the most used email delivery services are SendGrid (10,755 companies), Amazon SES (3,842 companies) and Mailchimp Transactional (3,244 companies), according to runsonwhat (October 2026). Large companies often run more than one tool in a category, so the same company can count for several.
Which email delivery services are most popular in the United States?
In the United States, the most used email delivery services are SendGrid (67,366 companies), Mailgun (17,538 companies) and Mailchimp Transactional (16,781 companies), based on companies runsonwhat has located there (October 2026). SendGrid has 46% of the Email Delivery matches among companies based in the United States.
Which email delivery services are most popular in the United Kingdom?
In the United Kingdom, the most used email delivery services are SendGrid (14,189 companies), Mailchimp Transactional (4,868 companies) and Mailgun (4,346 companies), based on companies runsonwhat has located there (October 2026). SendGrid has 40% of the Email Delivery matches among companies based in the United Kingdom.
Which email delivery services do IT services companies use?
IT services is the industry with the most Email Delivery matches, and its companies use SendGrid (13,051 companies), Amazon SES (4,443 companies) and Mailchimp Transactional (3,234 companies) most, according to runsonwhat (October 2026). Each tool's page breaks its customers down by industry, so you can check where a tool over-indexes.
Which email delivery services are companies adopting right now?
In the 30 days to October 2026, the most new adoptions runsonwhat recorded were for ImprovMX (120 companies), Resend (119 companies) and MailChannels (105 companies). A start is counted when a recheck finds a tool that the previous check of the same company, done the same way, did not.
How does runsonwhat rank email delivery services?
runsonwhat counts the companies where a public record shows each tool in use and ranks by that count. Sending services must be authorized in DNS, so they show up reliably in SPF includes, DKIM keys and the MX or return-path records of sending subdomains. A company counts only when a direct record backs it up. The full method is at https://www.runsonwhat.com/methodology.