This is a Java client for the Automatic Certificate Management Environment (ACME) protocol.

ACME is a protocol that a certificate authority (CA) and an applicant can use to automate the process of verification and certificate issuance.

This Java client helps connecting to an ACME server, and performing all necessary steps to manage certificates.

It is an independent open source implementation that is not affiliated with or endorsed by Let's Encrypt.

• Fully supports the ACME v2 protocol up to draft 09
• Easy to use Java API
• Requires JRE 8 (update 101) or higher
• Built with maven, packages available at Maven Central
• Small, only requires jose4j and slf4j as dependencies
• Extensive unit and integration tests

There are two versions of the ACME specification, ACME v1 and ACME v2.

ACME v1 is currently in production. It is supported by acme4j < 2.0, so use acme4j < 2.0 for production purposes!

At the moment, Let's Encrypt only provides an ACME v2 staging server for testing purposes. An ACME v2 production server is planned to be launched on Feburary 27th, 2018. acme4j >= 2.0 supports the ACME v2 protocol.

Let's Encrypt has not announced a sunset date for ACME v1 yet, so there is plenty of time for migration. acme4j < 2.0 will be maintained in the acmev1 branch until sunset of the ACME v1 protocol.

• Let's Encrypt does not support the tls-sni-02 challenge yet, while acme4j does not provide tls-sni-01 support any more. If you use tls-sni, do not upgrade to acme4j v2 yet!
• The acme4j v2 API is still subject to change.
• Integration tests do not fully cover all functions. The standard methods for creating an account, ordering, and downloading a certificate are tested. Other methods are not tested yet, and may not work as expected.

• See the online documentation about how to use acme4j.
• For a quick start, have a look at the source code of an example.

• Fork the Source code at GitHub. Feel free to send pull requests.
• Found a bug? File a bug report!

acme4j is open source software. The source code is distributed under the terms of Apache License 2.0.

• I would like to thank Brian Campbell and all the other jose4j developers. acme4j would not exist without your excellent work.
• Thanks to Daniel McCarney for his help with the ACME protocol, Pebble, and Boulder.
• I also like to thank everyone who contributed to acme4j.