ACME Go client library and a command line tool without 3rd party deps!

go get



ACME-complient Go client library and a command line tool. Neither has 3rd party dependencies. Also, see

Contents of this repo:

  • / - ACME client Go package. See godoc for acme package. The package has been imported to I will keep package mirroring crypto/acme/internal/acme until it becomes exported as
  • /cmd/acme/ - cli tool, similar to the official letsencrypt.

This package is a work in progress and makes no API stability promises.

command line tool usage

Quick install with go get -u

  1. You need to have a user account, registered with the CA. This is represented by an RSA private key.

    The easiest is to let acme tool generate it for you:

      acme reg

    If you already have a key or want to generate one manually:

      mkdir -p ~/config/acme
      openssl genrsa -out ~/config/acme/account.pem 2048
      acme reg

    The latter version assumes that default acme config dir is ~/config/acme. Yours may vary. Check with acme help reg.

    The "" in the example above is a contact argument. While some ACME CA may let you register without providing any contact info, it is recommended to use one. For instance a CA might need to notify cert owners with an update.

  2. Agree with the ACME CA Terms of Service.

    Before requesting your first certificate, you may need to agree with the terms of the CA. You can check the status of our account with:

      acme whoami

    and look for "Accepted: ..." line. If it says "no", check CA's terms document provided as a link in "Terms: ..." field and agree by executing:

      acme update -update
  3. Request a new certificate for your domain.

    The easiest way to do this is:

      acme cert

    The above command will generate a new certificate key (unless one already exists), and send a certifcate request. The location of the output files is ~/.config.acme, but depends on your environment. Check with acme help cert.

    If you don't want auto-generated cert key, one can always be generated upfront:

      openssl genrsa -out cert.key 2048

    in which case the cert command will look something like this:

      acme cert -k cert.key

    Note that for certificate request command to succeed, it needs to be executed in a way allowing for resolving authorization challenges (domain ownership proof). This typically means the command should be executed on the same host the domain is served from.

    If the latter is not possible, use -manual flag and follow the instructions:

      acme cert -manual


(c) Google, 2015. Licensed under Apache-2 license.