Validate client certificate

Use the validate-client-certificate policy to enforce that a certificate presented by a client to an API Management instance matches specified validation rules and claims such as subject or issuer for one or more certificate identities.

To be considered valid, a client certificate must match all the validation rules defined by the attributes at the top-level element and match all defined claims for at least one of the defined identities.

Use this policy to check incoming certificate properties against desired properties. Also use this policy to override default validation of client certificates in these cases:

  • If you have uploaded custom CA certificates to validate client requests to the managed gateway
  • If you configured custom certificate authorities to validate client requests to a self-managed gateway

For more information about custom CA certificates and certificate authorities, see How to add a custom CA certificate in Azure API Management.


Set the policy's elements and child elements in the order provided in the policy statement. Learn more about how to set or edit API Management policies.

Policy statement

    validate-revocation="true | false"
    validate-trust="true | false" 
    validate-not-before="true | false" 
    validate-not-after="true | false" 
    ignore-error="true | false">
            thumbprint="certificate thumbprint"
            serial-number="certificate serial number"
            common-name="certificate common name"
            subject="certificate subject string"
            dns-name="certificate DNS name"
            issuer-subject="certificate issuer"
            issuer-thumbprint="certificate issuer thumbprint"
            issuer-certificate-id="certificate identifier" />


Name Description Required Default
validate-revocation  Boolean. Specifies whether certificate is validated against online revocation list. Policy expressions aren't allowed.  No true
validate-trust  Boolean. Specifies if validation should fail in case chain cannot be successfully built up to trusted CA. Policy expressions aren't allowed. No true
validate-not-before Boolean. Validates value against current time. Policy expressions aren't allowed. No  true
validate-not-after  Boolean. Validates value against current time. Policy expressions aren't allowed. No  true
ignore-error  Boolean. Specifies if policy should proceed to the next handler or jump to on-error upon failed validation. Policy expressions aren't allowed. No false


Element Description Required
identities Add this element to specify one or more identity elements with defined claims on the client certificate. No

identity attributes

Name Description Required Default
thumbprint Certificate thumbprint. No N/A
serial-number Certificate serial number. No N/A
common-name Certificate common name (part of Subject string). No N/A
subject Subject string. Must follow format of Distinguished Name. No N/A
dns-name Value of dnsName entry inside Subject Alternative Name claim. No N/A
issuer-subject Issuer's subject. Must follow format of Distinguished Name. No N/A
issuer-thumbprint Issuer thumbprint. No N/A
issuer-certificate-id Identifier of existing certificate entity representing the issuer's public key. Mutually exclusive with other issuer attributes. No N/A



The following example validates a client certificate to match the policy's default validation rules and checks whether the subject and issuer name match specified values.

            subject="C=US, ST=Illinois, L=Chicago, O=Contoso Corp., CN=*"
            issuer-subject="C=BE, O=FabrikamSign nv-sa, OU=Root CA, CN=FabrikamSign Root CA" />

Next steps

For more information about working with policies, see: