# How can I monitor wildcard domains?

In Oh Dear, every subdomain is a distinct monitor. There's no "wildcard" monitor type, because from the outside each subdomain is a separate site with its own DNS, its own certificate, and its own potential to break.

Even if every tenant shares the same wildcard certificate today, that can change tomorrow: DNS could point `alice.example.com` to a new server, a tenant could get a dedicated certificate, or something else could drift. If you only monitor one subdomain and assume the rest are fine, you won't notice until a customer tells you.

## The recommended approach

Add each tenant (subdomain) as its own monitor. You'll get:

- Independent uptime and performance tracking per tenant
- Per-subdomain certificate checks (handy if a tenant ever moves off the wildcard cert)
- Per-subdomain DNS and domain monitoring

## Minimal-effort alternative

If you have hundreds of tenants and monitoring each is too much, the next best thing is to monitor a few representative subdomains and the main domain, so at least infrastructure-level outages don't go unnoticed.

## Automate it through the API

For multi-tenant apps, the cleanest approach is to have your provisioning code add and remove monitors as tenants come and go. We have both a [REST API](/docs/api/introduction) and an [official PHP SDK](/docs/tools-and-sdks/the-oh-dear-php-sdk) for exactly that.

That way, every new tenant starts being monitored from the moment it's created, with zero manual work.