I believe you can add 100 subdomains to an LE certificate which gets you pretty close to a wildcard IMO (if you have over 100 subdomains then buying a real wildcard cert is probably a negligible cost for your service).

This is not quite right. You can pack up to 100 hostnames into ONE cert. That might be useful if you are trying to avoid SNI issues on a single shared IP address.

However, you are limited to five subdomain registrations or renewals per seven day window. Since certs are only good for 90 days, you are effectively limited to 60 or so, and that only if you do some crazy timing acrobatics, carefully spread the registrations out over the full 90 days and never make a mistake.

So I would say, at this point, LE is not an effective replacement for a wildcard cert for many people.

Scroll down to "Rate Limits": https://community.letsencrypt.org/t/quick-start-guide/1631

They really need to change the rate limits to something more reasonable. Both per domain and per ip.

That would be nice, but with it being so easy to get a certificate, you could just add a new SSL cert when you add the new subdomain.

If there only wasn't the limit of 5 certificates per domain per week [1].

[1] https://community.letsencrypt.org/t/rate-limits-for-lets-enc...

When it comes to rate-limiting, example.com and foobar.example.com are treated as completely separate domains.

That would be pretty awesome, but it's not how I interpret the following: "This limit measures certificates issued for a given combination of Public Suffix + Domain (a 'registered domain')."

Do you have a source?

I do not believe this is true. That rate limit applies to second-level domains and all subdomains.

This is not true. I know from experience.

See the first point in https://community.letsencrypt.org/t/rate-limits-for-lets-enc...