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The Python asyncio client for the ACME protocol

Getting Started Source Code


Gufo ACME is a Python asyncio client for the ACME protocol.

The Automatic Certificate Management Environment (ACME) protocol defines a method for automated certificate signing, now widely used by services such as Let's Encrypt. Gufo ACME is a Python asyncio ACME client library that simplifies the protocol complexity with a straightforward and robust API.

Gufo ACME contains various clients which can be applied to your tasks:

Supported Certificate Authorities


Account Creation

Create an account and store state to the file.

client_key = AcmeClient.get_key()
async with AcmeClient(DIRECTORY, key=client_key) as client:
    await client.new_account(email)
    state = client.get_state()
with open(client_state_path, "wb") as fp:

Private Key Generation

To generate a private key in PEM format.

private_key = AcmeClient.get_domain_private_key()

Generate CSR

To generate a certificate signing request.

csr = AcmeClient.get_domain_csr(domain, private_key)

Sign Certificate

Sign the certificate using http-01 challenge:

CHALLENGE_DIR = "/www/acme/"

class SignAcmeClient(AcmeClient):
    async def fulfill_http_01(
        self, domain: str, challenge: AcmeChallenge
    ) -> bool:
        v = self.get_key_authorization(challenge)
        with open(os.path.join(CHALLENGE_DIR, challenge.token), "wb") as fp:
        return True

    async def clear_http_01(
        self: AcmeClient, domain: str, challenge: AcmeChallenge
    ) -> None:
        os.unlink(os.path.join(CHALLENGE_DIR, challenge.token))

async with SignAcmeClient.from_state(state) as client:
    cert = await client.sign(domain, csr)


  • Pure-Python implementation.
  • Asynchronous.
  • Fully typed.
  • Clean API.
  • Robust well-tested code.
  • 99+% test coverage.

On Gufo Stack

This product is a part of Gufo Stack - the collaborative effort led by Gufo Labs. Our goal is to create a robust and flexible set of tools to create network management software and automate routine administration tasks.

To do this, we extract the key technologies that have proven themselves in the NOC and bring them as separate packages. Then we work on API, performance tuning, documentation, and testing. The NOC uses the final result as the external dependencies.

Gufo Stack makes the NOC better, and this is our primary task. But other products can benefit from Gufo Stack too. So we believe that our effort will make the other network management products better.