Yes, no problem! Wildcard subdomains are fully supported.
You may specify a source like: *.example.com
An SSL certificate will be automatically installed for every new request on a given subdomain.
Note: a wildcard source will be counted as using 5 source domains. Many different subdomains under a wildcard (100+) are subject to our fair-use policy.
Note: we don't issue wildcard SSL certificates, as this would require DNS based domain validation, which changes for every renewal. For that reason, we request an seperate certificate per subdomain.