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Simple Let’s Encrypt client.

simp_le --email -f account_key.json \
  -f account_reg.json \
  -f fullchain.pem -f key.pem \
  -d -d --default_root /var/www/html \

For more info see simp_le --help.

N.B. this was originally a fork of, which is unmaintained and has some breakage due to bitrot. Thanks to @kuba for the original implementation.


  1. UNIX philosophy: Do one thing and do it well!
  2. simp_le --valid_min ${seconds?} -f cert.pem implies that cert.pem is valid for at at least valid_min (defaults to 2592000 seconds / 30 days). Register new ACME CA account if necessary. Issue new certificate if no previous key/certificate/chain found. Renew only if necessary.
  3. (Sophisticated) “manager” for ${webroot?}/.well-known/acme-challenge only. No challenges other than http-01. Existing web-server must be running already.
  4. No magical webserver auto-configuration.
  5. Owner of ${webroot?}/.well-known/acme-challenge must be able to run the script, without privilege escalation (sudo, root, etc.).
  6. crontab friendly: fully automatable - no prompts, etc.
  7. No configuration files. CLI flags as the sole interface! Users should write their own wrapper scripts or use shell aliases if necessary.
  8. Support multiple domains with multiple roots. Always create single SAN certificate per simp_le run.
  9. Flexible storage capabilities. Built-in simp_le -f fullchain.pem -f key.pem, simp_le -f chain.pem -f cert.pem -f key.pem, etc.
  10. Do not allow specifying output file paths. Users should symlink if necessary!
  11. No need to allow specifying an arbitrary command when renewal has happened, just check the exit code:
    • 0 if certificate data was created or updated;
    • 1 if renewal not necessary;
    • 2 in case of errors.
  12. --server (support multiple ACME v2 CAs).
  13. Support for revocation.
  14. Implicit agreement to the selected ACME CA's terms of service.


sudo ./
export PATH=$PWD/venv/bin:$PATH

Usage with Docker

If you want to use simp_le with Docker, have a look at simp_le for Docker.


Have a look at for some examples.

If you’re having problems feel free to open an issue to ask questions.

Change Log

Below is a summary of changes introduced in each release. Any user-visible changes must be recorded here. Note that the topmost entry sometimes represents the next (i.e. not yet released) version.

Releases occur approximately every two months, unless there is a pressing need to do otherwise (e.g. security & serious bug fixes), or no changes have been made since the last release.


  • Fix a minor standards conformance issue, see #155


  • Add missing dependency on the six package.


  • Add --use_alt_chain flag.


  • Fix a minor protocol conformance issue.
  • Fix some bitrot in the script (not applicable unless installing from the git repo).


  • Upgrade acme to 1.3 or later.
  • Fix a bug where simp_le failed to obtain a cert from BuyPass ACME.


  • Upgrade acme to 1.x


  • Fix an ACME v2 protocol non-conformity
  • Upgrade acme to 0.39.x


Please read these carefully, as this release includes a couple changes that may require changes when upgrading

  • Switch from ACME v1 to ACME v2 endpoints support. Support for ACME v1 endpoints has been dropped entirely. If you were previously passing the server endpoint via the --server flag, you will need to update it to point to a v2 endpoint (or simply remove it, to use Let's Encrypt's default v2 endpoint).
  • Persist account_reg.json in addition to account_key.json, and recover missing registration info if needed. You will now need to pass a ``-f account_reg.json`` option to simp_le
  • Remove the -f feature.
  • Drop official support for Python 2 and 3.4.
  • Add official support for Python 3.7 (in theory it should have worked before, but we are now testing with it).
  • Upgrade acme to 0.35.x


  • Upgrade acme to 0.33.x


  • Upgrade acme to 0.31.x


  • Upgrade acme to 0.29.x


  • Upgrade acme to 0.27.x


  • Upgrade acme to 0.25.x


  • Upgrade acme to 0.24.x


  • Add a workaround for some installation problems caused by a bug in pip.


  • Drop official support for Python 2.6
  • Upgrade acme to 0.22.x


  • Remove the ToS hash comparison, implicitly agree to CA's ToS if present
  • Add check for empty or corrupt cert/key files
  • Add some sanity checks for email syntax
  • Upgrade acme to 0.20.x


  • Implement the future-proofing mentioned in the 0.6.1 release notes. Future TOS changes should not break simp_le >= 0.6.2


  • Update the hash for the letsencrypt TOS. The TOS changed on November 15th, which broke previous releases. Future releases will not hard-code the hash, which should avoid this sort of problem in the future.


  • Drop official support for Python 3.3.
  • Disable self-verification; this was highly unreliable and resulted in spurrious warnings.
  • Improve argument sanity-checks and error messages.
  • Save account_key.json, even on failures
  • Clean temporary challenge files.
  • Upgrade acme to 0.19.x


  • Add a workaround for some installation problems caused by a bug in pip


  • Upgrade acme to 0.17.x


  • Upgrade acme to 0.16.x


  • Fix a bug where the version number was incorrectly reported
  • Upgrade acme to 0.15.x


  • Upgrade to acme 0.11.x


  • Change the package name; the original maintainer owns the simp_le PyPI package, and hasn't responded to requests to transfer it, so the package name is now 'simp_le-client'.


  • First release