Child pages
  • Guide to Third-Party AutoSSL Provider Modules
Skip to end of metadata
Go to start of metadata



Only advanced users should use this feature.


We added AutoSSL functionality to cPanel & WHM version 58, and custom AutoSSL provider modules in version 60.

AutoSSL provider modules allow your server's users to automatically secure locally-hosted domains on their accounts with certificates from that SSL certificate provider. We ship the cPanel (powered by Sectigo®) provider module with cPanel & WHM, and you can download a plugin to add the Let's Encrypt™ provider module. This document explains how to create your own provider module.

Module development work

When you develop your provider module, we recommend the following workflow:

  1. Research the supported parameters for your desired SSL certificate provider.
  2. Configure a module that subclasses the /usr/local/cpanel/Cpanel/SSL/Auto/ module with overrides that match the supported parameters for your certificate provider.


    We advise that you do not directly edit the /usr/local/cpanel/Cpanel/SSL/Auto/ file.

Authentication deployment workflow

After you develop and configure your provider module, we recommend the following workflow to deploy the module:

  1. Navigate to WHM's Manage AutoSSL interface (WHM >> Home >> SSL >> Manage AutoSSL).
  2. Select the provider module.
  3. Test the provider module with an account on a non-production server.
  4. Review the log files to confirm that an SSL certificate provided by the provider secures the account's domains.

AutoSSL provider workflow


AutoSSL provider modules reside in the following directories:

  • The /usr/local/cpanel/Cpanel/SSL/Auto/Provider/ directory — cPanel-provided modules.
  • The /var/cpanel/perl/Cpanel/SSL/Auto/Provider/ directory — Third-party modules. 

For example, a module for the third-party ExampleSSL's module would reside in the /var/cpanel/perl/Cpanel/SSL/Auto/Provider/ location.

Module function interfaces

The tables below contain the required, recommended, and inherited methods.



You must configure the following methods in the Cpanel::SSL::Auto::Provider class. If you do not configure a required method, it will fail with a Cpanel::Exception::NotImplemented exception.

Method nameDescriptionExample
renew_ssl_for_vhosts(USERNAME, VHOST1 => \@DOMAINS1, VHOST2 => DOMAINS2, ...)

Key-value pairs that declare each virtual host and which domains within those virtual hosts to secure.


The key represents the Apache server's name. However, this key may change in a future version.

'' => \@list1_of_domains_including_www_subdomains,

'' => \@list2_of_domains_including_www_subdomains

You can provide the following optional methods in your module:

Method nameDescriptionExample

This method declares when to begin the renewal process. If the certificate expires in this number of days or fewer, the system starts the renewal process.

If you do not set this value, the system waits until the certificate expires before it attempts to replace it.

return 15 ;

This method executes immediately after AutoSSL prints a provider name prints into the log file.

You can override the following optional methods in your module:

Method nameDescriptionExample


The maximum number of domains to request per certificate. This depends on the Certificate Authority's (CA) domain limits.

If you do not set this value, the system assumes that the CA does not limit the number of domains on a certificate.

return 100 ;

This method returns a list of additional key-value pairs that define additional properties for the provider module.

For example, terms_of_service defines the URL at which the API caller needs to accept in order to enable the module, which they do through the terms_of_service_accepted parameter.


This method sends information to the external provider, such as registration data.


This method resets the server's registration with the remote provider.



This method indicates whether the PEM-encoded certificate that you send to it comes from a valid AutoSSL provider and not a valid, non-AutoSSL provider. This method varies depending on the CA and the type of certificate that they issue.

If you do not define this method, the system assumes that nothing comes from this module.

return ( $parsed_certificate->{'issuer'}{'organizationalUnitName'} && $parsed_certificate->{'issuer'}{'organizationalUnitName'} eq $provider_name ) ? 1 : 0;

This method defines the provider's name that the interface displays.

return 'Bogus SSL Provider for Testing Purposes';

This method declares what to run when an administrator renames the account.

The OLDNAME value represents the previous domain, while the NEWNAME value represents the new domain.

return oldexample, newexample;

This method declares what to run when the administrator terminates the account.

The OLDNAME value represents the terminated account.

return oldexample ]

This method declares what to run when a user or administrator removes a domain from the account.

The OLDNAME value represents the username that you removed.

return oldexample ;

This method performs Domain Control Validation (DCV) as part of the AutoSSL vhost processing. The options for this method are:

  • username — A username.
  • domains — A list of domains.
  • dcv_method — A hash whose keys are entries in the domains argument. Each hash value displays the local DCV methods (for example, http) that succeeded for the associated domain.

With this method, AutoSSL will not pass domains to the renew_ssl_for_vhosts method that fail the provider’s DCV. This can mitigate certain issues that arise if cPanel & WHM’s local DCV succeeds but the provider or CA’s DCV fails.

username => 'username',
domains => [ '', ' ],
dcv_method => {
    '' => 'http',
    '' => 'http',


The following methods are inherited, and you should not override them:

Method nameDescriptionExample

start_logging (USERNAME)

This method starts the log for the declared user.

If you do not set the USERNAME value, the system notes that this is an AutoSSL run for all users.

resume_logging (START_TIME)

This method appends to an existing log. The START_TIME value is an ISO 8601 time value.

If a log does not exist for the START_TIME time value, the system throws an exception.



This method enters the MESSAGE text in to the log file. The LEVEL value can be one of the following:

  • success
  • info
  • warn
  • error
'success', 'I'm making a note here'
increase_log_indent_level()This method indents the entries in the log by one level. 
decrease_log_indent_level()This method outdents the entries in the log by one level. 
get_log_start_time()This method returns the time that this class instance started to log, in ISO 8601 time value. 

When AutoSSL finishes a check run, it sets that run's log to completed.

However, this method flags the log as in progress. This is useful when the module uses a separate queue to fetch the AutoSSL certificates, as the cPanel module does.

install_certificate (%OPTS)

This method installs an SSL certificate for Exim, Apache, and Dovecot®.


In cPanel & WHM version 60, this method also installs an SSL certificate for cpsrvd and cpdavd modules.

We may expand this method to install certificates for other services in future versions.

You must pass the following required arguments through this method:

  • web_vhost_name — The name of the virtual host on which to install the certificate. For more information about virtual host names, read our UAPI Functions - WebVhosts::list_domains documentation.
  • certificate_pem — The PEM-encoded certificate.
  • key_pem — The PEM-encoded key.

You can pass the following optional arguments:

  • cab_pem — The PEM-encoded CA-bundle, with newlines separating each certificate.
  • installing_user — The user for whom to install the certificate. This option attempts to install the certificate with the permission set of the user (instead of the root user). If the user does not possess the permission to install on the given virtual host, the system will display an exception. If you do not set this option, the system could install a certificate on the wrong user's account.


    We added the installing_user option in cPanel & WHM version 68


We strongly recommend that you use the install_certificate method instead of an API function to install certificates. This method improves speed and will not restart Apache and Dovecot for each certificate installation.

'web_vhost_name' => $vhost,  'certificate_pem' => $res->{ 'cert' },  'key_pem' => $key );


The following AutoSSL module outline demonstrates a minimal set of functionality.


This is not a fully-functional module. This only demonstrates basic workflow. Your implementation will require more internal logic. Also, this module does not demonstrate the necessary API calls that would allow your module to hook into your SSL certificate provider.

#Name your module properly to be a submodule of the parent referenced below:
package Cpanel::SSL::Auto::Provider::BogusSSLProvider;

use strict;
use warnings;

use parent qw( Cpanel::SSL::Auto::Provider );

# I use CPAN modules here as much as possible for clarity of examples, you can write your own custom parsers/requesters if you feel like it.
use HTTP::Tiny(); 

use JSON::MaybeXS();
use Crypt::X509();
use Crypt::OpenSSL::RSA();
use Crypt::OpenSSL::PKCS10();

# Set this value to whatever you think is a reasonable for the domain to begin requesting a new free certificate (as you may queue the DCV check). This is mostly to help ensure a seamless SSL coverage experience for users of your free certificates (instead of them having coverage gaps waiting on DCV).
sub DAYS_TO_REPLACE { return 15; }

# Set this to whatever maximum you allow within your signing infrastructure for DV certificates. For example, Let's Encrypt has a limit of 100 domains that can be on any given CSR they'll sign.

# Defines what your SSL Provider name will look like in the cPanel & WHM UIs and AutoSSL logs.
sub DISPLAY_NAME { return 'Bogus SSL Provider for Testing Purposes'; }

# The logic in this subroutine needs to accept an SSL certificate string (in PEM format) and be able to tell us if that certificate came from your provider.
# Retuns 1 if yes, 0 if no.
    my ( $self, $cert_pem ) = @_; 
	# To parse a PEM encoded certificate file, you may want to use a module like Crypt::X509 from CPAN. See

    my $parsed_certificate = Convert::X509->new($cert_pem);
    # It can be as simple as looking at what organization signed the cert, but whatever info you want to look at in the Certificate is acceptable.
    # Similarly, you may want to check that the *validity* period for your certificate matches the product type of your free certificate offering.
	# Convert::X509 has 'to' and 'from' subroutines that would be helpful in this regard.
    my $provider_name = "Internet Widget Signing Organizaton, pty";
    return ( $parsed_certificate->issuer =~ m/$provider_name/ ) ? 1 : 0;

# This optional method allows a provider to do Domain Control Validation (DCV) as part of the AutoSSL vhost processing. When this method is in place correctly, AutoSSL will forgo passing domains to {{renew_ssl_for_vhosts()}} that fail the provider’s DCV. This can mitigate certain issues that arise if, for some reason, cPanel & WHM’s local DCV succeeds but the provider/CA’s DCV fails.
sub get_dcv_errors {
    my ($self, %opts) = @_;
    my @dcv_errors;
    for my $domain ( @{ $opts{'domains'} } ) {
        my @these_dcv_errors = ...;    # “...” being whatever custom external DCV logic is needed
        push @dcv_errors, \@these_dcv_errors;
    return \@dcv_errors;

# This function is where the magic happens, as we actually make a request here to your servers, and then *do_something* with that.
# In this example, we're assuming that the DCV happens *instantaneously* and you are delivered a certificate in return (as with the Let's Encrypt provider).
# If your provider cannot do this, then I would suggest you make a companion script to this that references a queue of some sort for installing your SSL certs.

# Anyways, the autossl binary, when run, will pass in the account and a hash containing information on all vhosts and domains contained therein.
# The function can return anything, but should probably return undef, as nothing checks the return value. If something goes wrong here, we'd wan't you to throw an exception/die.
sub renew_ssl_for_vhosts {
    my ( $self, $account_name, %vh_domains ) = @_; 

    # Generate the key for the cPanel account. See for more information.
	# /dev/random exists on all supported platforms, so Crypt::OpenSSL::Random's random_seed function and then importing that seed should not be needed.
	my $key = Crypt::OpenSSL::RSA->generate_key(2048);

    my ( $csr, $cert, $payload, $res );

	# Each vhost on the account will need a separate CSR, as cPanel's Apache stack is setup to only allow one certificate per vhost.
    foreach my $vhost ( keys( %vh_domains ) ) { 
        # Create the CSR for the vhost
        $csr = _create_csr_for_vhost( $key,  @{( $vh_domains{$vhost} )} );

		# Generate any additional data you may want to send over to your HTTP cert requesting endpoint.
		# In this example, I'm making an assumption that you are going to POST over some data along with your CSR, but you can do whatever it is you need.
		_generate_dcv_files( $csr, @{( $vh_domains{$vhost} )} );

        # Request the signed Cert.
        $payload = { 'validation_type' => 'dcv', 'csr' => $csr };
        $res = HTTP::Tiny->new()->post_form( 'https://some.url.endpoint/my_ssl_api', $payload );
        $res = $res->{content} if length $res->{content};
        $res = JSON::MaybeXS::decode_json($res);
        # If we haven't thrown an exception by now, we've gotten a certificate. Hooray! Let's go ahead and install it.
        $res = eval { $self->install_certificate( 'web_vhost_name' => $vhost, 'certificate_pem' => $res->{'cert'}, 'key_pem' => $key->get_private_key_string() ); };
        warn $@ if $@;
    # If we've gotten here, we're groovy. The AutoSSL logger will report great success to the user regarding the AutoSSL check *for this account*.
    # Any exceptions/warnings thrown earlier will be presented to the administrator in the autossl log.

# A simple skeleton function for creating a CSR for a vhost.
# See for a CPAN module that can help here.
sub _create_csr_for_vhost {
    my ( $key, @domains ) = @_;
    my $req = Crypt::OpenSSL::PKCS10->new_from_rsa($key);

	# Add whatever extensions, etc. you'd need in general for your request

	foreach my $domain ( @domains ) {
		# Add whatever you might need to add per domain for your request

	# Get the CSR in PEM format for us to return.
	my $csr = $req->get_pem_req();
	return $csr;

# Do something here that would generate the DCV files in the places you would normally look for DCV files on a domain on your end.
# In this example, I'm iterating over the array of domains in a vhost we passed in above. I've also added the CSR text in case we wanna use that
# for some reason here. Pass in whatever you need here. If parsing the CSR is needed, use
# If you want a CPAN module that can help for writing your files, use File::Slurp::write_file -- see
sub _generate_dcv_files {
	my ( $csr, @domains ) = @_;
	my $something;
	foreach my $domain ( @domains ) {
		#Create your DCV files by whatever means you deem necessary
    # Presumably whatever you want to return gets populated within the loop if you need to consume this information later.
	return $something;