Due to the large number of requests to support DNS providers to resolve DNS challenges, it became impractical and infeasible to maintain and test all DNS providers in the main cert-manager repository.
For this reason, it was decided that new DNS providers should be supported out-of-tree by way of external webhooks.
To implement an external DNS provider webhook, it is recommended to base your implementation on the cert-manager webhook-example.
There's further information available in the configuration section:
If you're struggling with creating a new DNS webhook, reach out on Slack!