Oh Dear! consists of several checks to make your life as a developer or sysadmin easier. In general, there are 4 kinds of categories that we validate on your behalf.
- Uptime: as soon as one of your sites is down, we can notify you.
- SSL/TLS health: if a certificate is due to expire, has missing certificates in its chains or uses SHA-1 hashing, we'll let you know.
- Content validation: we crawl your sites and will notify you when we detected mixed content.
- Broken links: we crawl your site and will notify you when we detected a broken link.
All the ip addresses Oh Dear! uses to check your sites are listed on this page.
Each check is further described in more detail.