Download websites that use Sendgrid

About Sendgrid

A site that sends mail through SendGrid usually shows no sign of it on the page a visitor loads. Email infrastructure sits behind the application, in message headers, in the DNS records that authorise a sender, in the tracking domain that rewrites links, and in the API calls a server makes once a form has been submitted. Detection here rests on indirect evidence rather than on a script tag, and the honest reading of a row in the Email column is that we found a signature consistent with the service, not that we watched an email leave.

The inference is still worth a great deal, because programmatic email is a symptom of an application. Password resets, receipts, order confirmations, invitations and alerts are sent by software, not by a person with a campaign calendar. Finding this provider on a domain is a reasonable proxy for a site that has users rather than only readers, and it separates working products from brochures more cleanly than most front-end signals do.

The negative case is informative too. A domain with a working checkout, a login form and no visible sending infrastructure of any kind is either running its own mail servers, which is rare and usually deliberate, or is using a provider that leaves no public trace. Both of those are worth knowing about a prospect before a conversation starts.

Founded in 2009 and now owned by Twilio, the service belongs to a broader consolidation of developer-facing communication tools into a few platforms. For a competitor that consolidation is the opening. The buying decision was made by an engineer, often long ago, and it gets revisited when deliverability degrades, when pricing changes or when a parent company reorganises its product line.

As of September 2026 the dataset records 902,418 sites carrying it, with 622,153 in United States and .com as the domain ending we see most often. The American concentration is not only a market fact. API-first email tooling was sold, priced and documented for a developer audience that formed there first, and the rest of the footprint follows the spread of that model rather than the distribution of email itself.

Deliverability consultants, competing providers, security researchers mapping sender infrastructure and analysts sizing a market all want the same thing, and a single domain lookup cannot give it to them. A list lets you count providers inside a vertical, compare two countries, or diff one month against the next to find the domains that switched. One caution belongs with any such analysis. A domain can use several senders at once, marketing through one and transactional mail through another, so a row should be read as evidence of use and never as exclusive ownership of a customer.

The same caution applies to absence. Our detection catches what a public crawl can see, which means a site whose mail passes entirely through a private backend, with no rewritten links and no delegated subdomain, will simply not appear. Treat the file as a strong sample of visible senders, filter it to the segment you care about, and use the gaps as questions rather than as answers.