What is a certificate authority (CA)?

A certificate authority, or CA, is an organisation that verifies who controls a domain and issues the SSL certificate for it. Browsers and operating systems ship with a list of authorities they trust, and a certificate is accepted only if it leads back to one of them.

How does a CA decide to issue a certificate?

For most certificates it checks that the applicant controls the domain, by placing a file on the site, adding a DNS record or answering an email. More expensive types also verify the organisation behind the site.

Free or paid authority?

Free authorities such as Let's Encrypt issue short-lived certificates through automation, which suits most sites. Paid authorities add longer support, warranties and organisation validation. For a typical client site the difference is mostly how renewal is handled.

Why does the CA matter when something breaks?

When renewal fails, the cause is often at the CA side of the process: a validation step that no longer passes, a rate limit or a closed account. Knowing who issued a certificate tells you where to look. The SSL certificate checker shows the issuer.

Where Datumboard fits

Datumboard puts the signals behind this in one dashboard for your client sites and side projects. It is in early access, and you can join the list below.