# The most used email delivery services

As of October 2026, the most used of the 20 email delivery services runsonwhat tracks is SendGrid, found at 189,002 companies, ahead of Amazon SES (58,364) and Mailchimp Transactional (56,116).

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

| # | Tool | Companies | Share of category | Last 30 days | Most popular with |
|---|---|---|---|---|---|
| 1 | [SendGrid](https://www.runsonwhat.com/reverse/sendgrid) | 189,002 | 40% | +55 −4 | 1,001–5,000 employees (1.6×) |
| 2 | [Amazon SES](https://www.runsonwhat.com/reverse/ses) | 58,364 | 12% | +34 −10 | 1,001–5,000 employees (2.0×) |
| 3 | [Mailchimp Transactional](https://www.runsonwhat.com/reverse/mandrill) | 56,116 | 12% | +16 −3 | 1,001–5,000 employees (1.7×) |
| 4 | [Mailgun](https://www.runsonwhat.com/reverse/mailgun) | 47,478 | 10% | +59 −6 | – |
| 5 | [Resend](https://www.runsonwhat.com/reverse/resend) | 25,276 | 5.4% | +123 | 1–10 employees (4.0×) |
| 6 | [Mailjet](https://www.runsonwhat.com/reverse/mailjet) | 24,124 | 5.1% | +3 −4 | 1,001–5,000 employees (1.7×) |
| 7 | [MailChannels](https://www.runsonwhat.com/reverse/mailchannels) | 21,914 | 4.7% | +107 −2 | – |
| 8 | [Postmark](https://www.runsonwhat.com/reverse/postmark) | 15,582 | 3.3% | +9 −4 | Insurance (3.8×) |
| 9 | [Elastic Email](https://www.runsonwhat.com/reverse/elasticemail) | 9,124 | 1.9% | +2 −3 | Non-profit Organization Management (2.2×) |
| 10 | [SparkPost](https://www.runsonwhat.com/reverse/sparkpost) | 6,012 | 1.3% | +5 | Non-profit Organization Management (2.2×) |
| 11 | [SMTP2GO](https://www.runsonwhat.com/reverse/smtp2go) | 4,435 | 0.94% | +100 −1 | Construction (2.4×) |
| 12 | [MailerSend](https://www.runsonwhat.com/reverse/mailersend) | 3,482 | 0.74% | +37 | Software (1.6×) |
| 13 | [AuthSMTP](https://www.runsonwhat.com/reverse/authsmtp) | 2,392 | 0.51% | +49 | Hospitality (3.6×) |
| 14 | [turboSMTP](https://www.runsonwhat.com/reverse/turbosmtp) | 2,275 | 0.48% | +37 −1 | Construction (2.6×) |
| 15 | [Flowmailer](https://www.runsonwhat.com/reverse/flowmailer) | 1,811 | 0.38% | +59 | Staffing and Recruiting (7.3×) |
| 16 | [ImprovMX](https://www.runsonwhat.com/reverse/improvmx) | 938 | 0.20% | +120 | 1–10 employees (3.1×) |
| 17 | [Forward Email](https://www.runsonwhat.com/reverse/forward-email) | 734 | 0.16% | +27 | Software (2.0×) |
| 18 | [Mailtrap](https://www.runsonwhat.com/reverse/mailtrap) | 696 | 0.15% | +16 | Automotive (2.4×) |
| 19 | [Validity](https://www.runsonwhat.com/reverse/validity) | 610 | 0.13% | +3 −1 | Publishing (15×) |
| 20 | [SocketLabs](https://www.runsonwhat.com/reverse/socketlabs) | 521 | 0.11% | +1 | Financial Services (1.7×) |

Share is each tool's part of all 470,886 matches in this category; a company using two tools counts for both.

## 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 runsonwhat finds 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.

## 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 (189,002 companies), Amazon SES (58,364 companies) and Mailchimp Transactional (56,116 companies), according to runsonwhat. SendGrid alone accounts for 40% of the 470,886 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: 189,002 companies show public evidence of SendGrid, against 58,364 for Amazon SES (3.2× as many), according to runsonwhat (October 2026). Mailchimp Transactional is third with 56,116.

### Which email delivery services do small businesses use most?

Among companies with up to 50 employees, the most used email delivery services are SendGrid (85,140 companies), Mailchimp Transactional (23,758 companies) and Mailgun (23,097 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 (10,760 companies), Amazon SES (3,841 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 (67,373 companies), Mailgun (17,539 companies) and Mailchimp Transactional (16,780 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 (4,867 companies) and Mailgun (4,345 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 (13,053 companies), Amazon SES (4,445 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 Resend (123 companies), ImprovMX (120 companies) and MailChannels (107 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.

### Which email delivery services are losing customers?

In the 30 days to October 2026, more companies stopped than started using Mailjet (4 stopped, 3 started) and Elastic Email (3 stopped, 2 started), according to runsonwhat's rechecks. Short-term moves are small next to each tool's total, so read them as signals rather than trends.

### What is SendGrid's market share among email delivery services?

SendGrid has 40% of the Email Delivery matches runsonwhat has found (189,002 companies of 470,886), as of October 2026; Amazon SES has 12%. This is share of companies with public evidence of each tool, not share of revenue or seats, and a company that runs two tools counts for both.

### 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.

## Related categories

- [Workspace](https://www.runsonwhat.com/tools/email-workspace.md)
- [Collaboration](https://www.runsonwhat.com/tools/collaboration.md)
- [Dev Tools](https://www.runsonwhat.com/tools/developer-tools.md)
- [People & HR](https://www.runsonwhat.com/tools/hr-recruiting.md)
- [Finance & Legal](https://www.runsonwhat.com/tools/finance-legal.md)
- [Security & Compliance](https://www.runsonwhat.com/tools/security-compliance.md)

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Source: runsonwhat, https://www.runsonwhat.com/tools/email-delivery (updated October 2026). Counts are companies with direct public evidence of the tool (DNS records, certificates, website code, a real-browser crawl, subprocessor lists), so they are lower bounds. Methodology: https://www.runsonwhat.com/methodology.