Configure mTLS Authentication for a Client

Learn how to configure mTLS authentication for a client with the Management API and Auth0 Dashboard.

Auth0 Dashboard
Management API

You can use the Auth0 Dashboard to configure mTLS for a client to enable mTLS client authentication to the Authorization Server.

Navigate to Auth0 Dashboard > Applications > Applications.
Select the application you want to use with mTLS or create a new application.
Select the Credentials tab.
Choose the required Authentication Method, which can be either:
- mTLS with a self-signed certificate
- mTLS with a certificate authority signed certificate
Once you select your preferred type of certificate, you can:
- Assign an existing credential (certificate) to the client application
- Add a new credential by uploading a certificate

Use the Auth0 Management API to configure mTLS for a client.

The following examples specify $management_access_token, or a Management API access token. This must be replaced with an access token that contains at least the following scopes:

create:custom_domains
read:custom_domains
create:clients
update:clients
update:client_credentials
update:client_keys
update:tenant_settings

To learn more about retrieving an access token with the required scopes, read Get Access Tokens.

Self-signed certificates

Use self-signed certificates to verify the client’s identity during mTLS authentication. However, self-signed certificates have the following limitations:

Self-signed certificates are not accepted by some cloud providers such as Amazon.
To ensure the stability of our platform, Auth0 limits customers to two registered certificates.

Generate a certificate

To authenticate using self-signed mTLS, you must create a new self-signed client certificate.The following code sample generates a new self-signed certificate:

openssl req -x509 -newkey rsa:2048 -keyout key.pem -out cert.pem -sha256 -days 365 -nodes -subj "/C=XX/ST=StateName/L=CityName/O=CompanyName/OU=CompanySectionName/CN=CommonNameOrHostname"

Because the certificate must be sent as a single-line JSON string value, every literal newline character in the PEM file must be JSON-escaped before you pass it to Auth0. Replace each line break with \n (or \r\n if the file uses Windows-style line endings). Many HTTP tools and libraries do not do this conversion for you, so verify the escaping before sending the request. For example:

Create a new client

To create a new client, make a POST call to the /clients endpoint with the following payload:

$client_name: the name for the new client
$credential_name: the name for the public key
$credential_certificate: the content of the cert.pem file generated in the previous step

Auth0 CLI
cURL

Using the Auth0 CLI? If you haven’t already, set up and authenticate your CLI session before running this command.

auth0 api post "clients" \
  --data '{
    "name": "$client_name",
    "app_type": "non_interactive",
    "client_authentication_methods": {
      "self_signed_tls_client_auth": {
        "credentials": [{
          "name": "$credential_name",
          "credential_type": "x509_cert",
          "pem": "$credential_certificate"
        }]
      }
    },
    "jwt_configuration": {
      "alg": "RS256"
    }
  }'

curl --location --request POST 'https://$tenant/api/v2/clients' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "name": "$client_name",
  "app_type": "non_interactive",
  "client_authentication_methods": {
    "self_signed_tls_client_auth": {
      "credentials": [{ 
        "name": "$credential_name", 
        "credential_type": "x509_cert", 
        "pem": "$credential_certificate"
      }]
    }
  },
  "jwt_configuration": {
    "alg": "RS256"
  }
}'

For more information, see the Create a client API documentation.

Patch an existing client

You can update an existing client to accept mTLS client authentication by removing any value in the token_endpoint_auth_method field and creating values in the client_authentication_methods field.

Once you have configured your client for mTLS, you won’t be able to authenticate using the Client Secret unless you configure the token_endpoint_auth_method to stop using mTLS. To learn more, read Revert a client to use a Client Secret.

Create the credential resource

After you generate a certificate, create the credential resource:

Auth0 CLI
cURL

auth0 api post "clients/$client_id/credentials" \
  --data '{
    "name": "$credential_name",
    "credential_type": "x509_cert",
    "pem": "$credential_certificate"
  }'

curl --location --request POST 'https://$tenant/api/v2/clients/$client_id/credentials' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "name": "$credential_name", 
  "credential_type": "x509_cert", 
  "pem": "$credential_certificate"
}'

Auth0 returns a credential ID in the response that you will need to associate the credential with the client.For more information, see the Create a client credential API documentation.

Associate the credential with the client and disable `token_endpoint_auth_method`

Uploaded credentials are not automatically enabled for client authentication. You need to update the client authentication to use the new self-signed client certificate.The following PATCH request sets the token_endpoint_auth_method to null, thus disabling Client Secret authentication. It also updates client_authentication_methods with the credential ID:

Auth0 CLI
cURL

auth0 api patch "clients/$client_id" \
  --data '{
    "token_endpoint_auth_method": null,
    "client_authentication_methods": {
      "self_signed_tls_client_auth": {
        "credentials": [{ "id": $credential.id }]
      }
    }
  }'

curl --location --request PATCH 'https://$tenant/api/v2/clients/$client_id' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "token_endpoint_auth_method": null, 
  "client_authentication_methods": {
    "self_signed_tls_client_auth": {
      "credentials": [{ "id": $credential.id }]
    }
  }
}'

Once this request has completed, a Client Secret will no longer be accepted and clients must authenticate using mTLS.For more information, see the Update a client API documentation.

Certificate authority signed certificates

Unlike self-signed certificates that are generated by the client and have no trust chain, certificate authority (CA) signed certificates are considered more trustworthy since they are issued by a trusted third party. CA-signed certificates are the only type of certificate accepted by some cloud providers such as Amazon.CA-signed certificates have embedded in their identity information the notion of a Distinguished Name (DN). While each individual certificate created by a given CA is unique, they can share a common DN. When using CA-signed certificates, Auth0 stores the DN and compares forwarded client certificates with registered DNs.

Generate a certificate

The method of generating a CA-signed client certificate is highly dependent on the Public Key Infrastructure and outside of the scope of this document. We recommend generating at least a 2048-bit RSA key pair.

Create a new client

To create a client, make a POST call to the /clients endpoint with the following payload:

$client_name: the name for the new client
$credential_name: the name for the public key
$credential_certificate: the content of the PEM file generated by the CA

Auth0 CLI
cURL

auth0 api post "clients" \
  --data '{
    "name": "$client_name",
    "app_type": "non_interactive",
    "client_authentication_methods": {
      "tls_client_auth": {
        "credentials": [{
          "name": "$credential_name",
          "credential_type": "cert_subject_dn",
          "pem": "$credential_certificate"
        }]
      }
    },
    "jwt_configuration": {
      "alg": "RS256"
    }
  }'

curl --location --request POST 'https://$tenant/api/v2/clients' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "name": "$client_name",
  "app_type": "non_interactive",
  "client_authentication_methods": {
    "tls_client_auth": {
      "credentials": [{ 
        "name": "$credential_name", 
        "credential_type": "cert_subject_dn", 
        "pem": "$credential_certificate"
      }]
    }
  },
  "jwt_configuration": {
    "alg": "RS256"
  }
}'

Instead of passing the full PEM file, you can also pass the subject DN. The subject DN must match the extracted Distinguished Name (DN) of the client certificates sent during the mTLS handshake.

Subject DN extraction may differ between different ecosystems. The most reliable way to guarantee that the authorization server will match the subject DN is to upload the whole PEM file.

The following POST request creates a new client with the subject DN:

Auth0 CLI
cURL

auth0 api post "clients" \
  --data '{
    "name": "$client_name",
    "app_type": "non_interactive",
    "client_authentication_methods": {
      "tls_client_auth": {
        "credentials": [{
          "name": "$credential_name",
          "credential_type": "cert_subject_dn",
          "subject_dn": "C=XX\nST=StateName\nL=CityName\nO=CompanyName\nOU=CompanySectionName\nCN=CommonNameOrHostname"
        }]
      }
    },
    "jwt_configuration": {
      "alg": "RS256"
    }
  }'

curl --location --request POST 'https://$tenant/api/v2/clients' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "name": "$client_name",
  "app_type": "non_interactive",
  "client_authentication_methods": {
    "tls_client_auth": {
      "credentials": [{ 
        "name": "$credential_name", 
        "credential_type": "cert_subject_dn", 
        "subject_dn": "C=XX\nST=StateName\nL=CityName\nO=CompanyName\nOU=CompanySectionName\nCN=CommonNameOrHostname"
      }]
    }
  },
  "jwt_configuration": {
    "alg": "RS256"
  }
}'

For more information, see the Create a client API documentation.

Patch an existing client

If you don’t want to create a new client to use mTLS, you can update an existing client to accept mTLS client authentication. This involves removing any value in the token_endpoint_auth_method field and creating values in the client_authentication_methods field.

Create the credential resource

Once you have generated a key pair exclusively for mTLS, create the credential resource. Make the following POST request to the /clients/$client_id/credentials endpoint:

Auth0 CLI
cURL

auth0 api post "clients/$client_id/credentials" \
  --data '{
    "name": "$credential_name",
    "credential_type": "cert_subject_dn",
    "pem": "$credential_certificate"
  }'

curl --location --request POST 'https://$tenant/api/v2/clients/$client_id/credentials' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "name": "$credential_name", 
  "credential_type": "cert_subject_dn", 
  "pem": "$credential_certificate"
}'

Instead of passing the full PEM file, you can pass the subject DN. The subject DN must match the extracted Distinguished Name (DN) of the client certificates sent during the mTLS handshake.The following code sample creates the credential resource using the Subject DN:

Auth0 CLI
cURL

auth0 api post "clients/$client_id/credentials" \
  --data '{
    "name": "$credential_name",
    "credential_type": "cert_subject_dn",
    "subject_dn": "C=XX\nST=StateName\nL=CityName\nO=CompanyName\nOU=CompanySectionName\nCN=CommonNameOrHostname"
  }'

curl --location --request POST 'https://$tenant/api/v2/clients/$client_id/credentials' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "name": "$credential_name", 
  "credential_type": "cert_subject_dn", 
  "subject_dn": "C=XX\nST=StateName\nL=CityName\nO=CompanyName\nOU=CompanySectionName\nCN=CommonNameOrHostname"
}'

When using either method, remember that the credential ID that gets returned in the response is needed to associate the credential with the client.For more information, see the Create a client credential API documentation.

Associate the credential with the client and disable `token_endpoint_auth_method`

Although we have created the credential, we have not yet associated the credential with the client.To do so, update client_authentication_methods by making the following PATCH request to the /clients endpoint. In the same request, set token_endpoint_auth_method to null:

Auth0 CLI
cURL

auth0 api patch "clients/$client_id" \
  --data '{
    "token_endpoint_auth_method": null,
    "client_authentication_methods": {
      "tls_client_auth": {
        "credentials": [{ "id": $credential.id }]
      }
    }
  }'

curl --location --request PATCH 'https://$tenant/api/v2/clients/$client_id' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "token_endpoint_auth_method": null, 
  "client_authentication_methods": {
    "tls_client_auth": {
      "credentials": [{ "id": $credential.id }]
    }
  }
}'

Once this request has completed, the client can only be authenticated using mTLS.For more information, see the Update a client API documentation.

Revert a client to use a Client Secret

To restore your client’s configuration to authenticate using a Client Secret, disable client_authentication_methods and re-enable token_endpoint_auth_method with your desired authentication method.In the following PATCH request, set token_endpoint_auth_method to client_secret_post to re-enable Client Secret authentication:

Auth0 CLI
cURL

auth0 api patch "clients/$client_id" \
  --data '{
    "token_endpoint_auth_method": "client_secret_post",
    "client_authentication_methods": null
  }'

curl --location --request PATCH 'https://$tenant/api/v2/clients/$client_id' \
  --header 'Authorization: Bearer $management_access_token' \
  --header 'Content-Type: application/json' \
  --data-raw '{
  "token_endpoint_auth_method": "client_secret_post",
  "client_authentication_methods": null
}'

For more information, see the Update a client API documentation.

Quickstarts

Applications

Configure mTLS Authentication for a Client

Self-signed certificates

Generate a certificate

Create a new client

Patch an existing client

Create the credential resource

Associate the credential with the client and disable `token_endpoint_auth_method`

Certificate authority signed certificates

Generate a certificate

Create a new client

Patch an existing client

Create the credential resource

Associate the credential with the client and disable `token_endpoint_auth_method`

Revert a client to use a Client Secret

Learn more

​Self-signed certificates

Generate a certificate

Create a new client

Patch an existing client

Create the credential resource

Associate the credential with the client and disable token_endpoint_auth_method

​Certificate authority signed certificates

Generate a certificate

Create a new client

Patch an existing client

Create the credential resource

Associate the credential with the client and disable token_endpoint_auth_method

​Revert a client to use a Client Secret

​Learn more

Self-signed certificates

Associate the credential with the client and disable `token_endpoint_auth_method`

Certificate authority signed certificates

Associate the credential with the client and disable `token_endpoint_auth_method`

Revert a client to use a Client Secret

Learn more