ACME and EAB: Support for Web Servers (Status as of 10/2025)

14 Oct 2025 | Jindřich Zechmeister

Learn how to use ACME and EAB to automate TLS certificates. We compare support on Nginx, Apache, LiteSpeed, and others, tips for DigiCert, and hassle-free implementation.

ACME serves to manage the lifecycle of certificates - from request and installation to renewal. You have been able to use ACME on SSLmarket for several years. Let's take a look at the state of ACME support for individual web servers.

ACME protocol and web servers

The ACME protocol was originally used independently through clients, where you would issue a TLS certificate via some program and this "ACME client" would also install it on the web server. The most well-known ACME client is Certbot, and the initial support for the Apache web server gradually expanded, even to Windows Server and IIS.

The current trend is the integration of the ACME client directly into the web server to obtain and deploy the certificate in a compatible way without needing additional software or interventions. You have "all-in-one". An example of a web server with a built-in ACME client is Caddy or OpenLiteSpeed. Recently, Nginx also gained native ACME support, but it still does not support EAB, so it cannot be used for DigiCert.

What is EAB in ACME

EAB (External Account Binding) is a mechanism in ACME that assigns your ACME client to a specific account at the certification authority. When creating an ACME account, the client uses a pair of data from the CA - the KID identifier and a secret HMAC key - to "pair" with your organization's account. Thanks to this, the CA knows who is requesting the certificate and can apply internal rules and issue even enterprise or paid certificates according to the account settings. EAB does not replace domain verification (HTTP-01/DNS-01); it only ensures that the request comes from an authorized account.

SSLmarket offers a completely unique feature - an overview of all certificates issued via ACME, which we will import to your user account with all metadata and information.

Current ACME support on web servers

The table below shows an overview of ACME protocol integration for individual web servers. Most already have ACME integrated and if they also support EAB, you can use certificates from DigiCert and automate them. You can easily and freely get ACME access in your SSLmarket account.

Conclusion

You can use ACME to automate certificates practically anywhere. Basic instructions can be found in our help. If you encounter any difficulties or have questions, do not hesitate to contact our customer support.