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Certes is an ACME client runs on .NET 4.5+ and .NET Standard 2.0+, supports ACME v2 and wildcard certificates. It is aimed to provide an easy to use API for managing certificates during deployment processes.


Install Certes nuget package into your project:

Install-Package Certes

or using .NET CLI:

dotnet add package Certes

Let's Encrypt is the primary CA we supported. It's recommend testing against staging environment before using production environment, to avoid hitting the rate limits.


Creating new ACME account:

var acme = new AcmeContext(WellKnownServers.LetsEncryptStagingV2);
var account = await acme.NewAccount("", true);

// Save the account key for later use
var pemKey = acme.AccountKey.ToPem();

Use an existing ACME account:

// Load the saved account key
var accountKey = KeyFactory.FromPem(pemKey);
var acme = new AcmeContext(WellKnownServers.LetsEncryptStagingV2, accountKey);
var account = await acme.Account();

See API doc for additional operations.


Place a wildcard certificate order (DNS validation is required for wildcard certificates)

var order = await acme.NewOrder(new[] { "*" });

Generate the value for DNS TXT record

var authz = (await order.Authorizations()).First();
var dnsChallenge = await authz.Dns();
var dnsTxt = acme.AccountKey.DnsTxt(dnsChallenge.Token);

Add a DNS TXT record to with dnsTxt value.

For non-wildcard certificate, HTTP challenge is also available

var order = await acme.NewOrder(new[] { "" });


Get the token and key authorization string

var authz = (await order.Authorizations()).First();
var httpChallenge = await authz.Http();
var keyAuthz = httpChallenge.KeyAuthz;

Save the key authorization string in a text file, and upload it to<token>


Ask the ACME server to validate our domain ownership

await challenge.Validate();


Download the certificate once validation is done

var privateKey = KeyFactory.NewKey(KeyAlgorithm.ES256);
var cert = await order.Generate(new CsrInfo
    CountryName = "CA",
    State = "Ontario",
    Locality = "Toronto",
    Organization = "Certes",
    OrganizationUnit = "Dev",
    CommonName = "",
}, privateKey);

Export full chain certification

var certPem = cert.ToPem();

Export PFX

var pfxBuilder = cert.ToPfx(privateKey);
var pfx = pfxBuilder.Build("my-cert", "abcd1234");

Check the APIs for more details.

For ACME v1, please see the doc here.


The CLI is available as a dotnet global tool. .NET Core Runtime 2.1+ is required to use dotnet tools.

To install Certes CLI (you may need to restart the console session if this is the first dotnet tool installed)

dotnet tool install --global dotnet-certes

See CLI usage, or simply use the --help option to get started

certes --help

Also check this AppVeyor script for renewing certificates on Azure apps.


We use SemVer for versioning. For the versions available, see the tags on this repository.

Also check the changelog to see what's we are working on.

CI Status

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