Policy

An Identity and Access Management (IAM) policy, which specifies access controls for Google Cloud resources.

APolicy is a collection ofbindings. Abinding binds one or moremembers, or principals, to a singlerole. Principals can be user accounts, service accounts, Google groups, and domains (such as G Suite). Arole is a named list of permissions; eachrole can be an IAM predefined role or a user-created custom role.

For some types of Google Cloud resources, abinding can also specify acondition, which is a logical expression that allows access to a resource only if the expression evaluates totrue. A condition can add constraints based on attributes of the request, the resource, or both. To learn which resources support conditions in their IAM policies, see theIAM documentation.

JSON example:

    {      "bindings": [        {          "role": "roles/resourcemanager.organizationAdmin",          "members": [            "user:mike@example.com",            "group:admins@example.com",            "domain:google.com",            "serviceAccount:my-project-id@appspot.gserviceaccount.com"          ]        },        {          "role": "roles/resourcemanager.organizationViewer",          "members": [            "user:eve@example.com"          ],          "condition": {            "title": "expirable access",            "description": "Does not grant access after Sep 2020",            "expression": "request.time < timestamp('2020-10-01T00:00:00.000Z')",          }        }      ],      "etag": "BwWWja0YfJA=",      "version": 3    }

YAML example:

    bindings:    - members:      - user:mike@example.com      - group:admins@example.com      - domain:google.com      - serviceAccount:my-project-id@appspot.gserviceaccount.com      role: roles/resourcemanager.organizationAdmin    - members:      - user:eve@example.com      role: roles/resourcemanager.organizationViewer      condition:        title: expirable access        description: Does not grant access after Sep 2020        expression: request.time < timestamp('2020-10-01T00:00:00.000Z')    etag: BwWWja0YfJA=    version: 3

For a description of IAM and its features, see theIAM documentation.

JSON representation
{"version":integer,"bindings":[{object (Binding)}],"etag":string}
Fields
version

integer

Specifies the format of the policy.

Valid values are0,1, and3. Requests that specify an invalid value are rejected.

Any operation that affects conditional role bindings must specify version3. This requirement applies to the following operations:

  • Getting a policy that includes a conditional role binding
  • Adding a conditional role binding to a policy
  • Changing a conditional role binding in a policy
  • Removing any role binding, with or without a condition, from a policy that includes conditions

Important: If you use IAM Conditions, you must include theetag field whenever you callsetIamPolicy. If you omit this field, then IAM allows you to overwrite a version3 policy with a version1 policy, and all of the conditions in the version3 policy are lost.

If a policy does not include any conditions, operations on that policy may specify any valid version or leave the field unset.

To learn which resources support conditions in their IAM policies, see theIAM documentation.

bindings[]

object (Binding)

Associates a list ofmembers, or principals, with arole. Optionally, may specify acondition that determines how and when thebindings are applied. Each of thebindings must contain at least one principal.

Thebindings in aPolicy can refer to up to 1,500 principals; up to 250 of these principals can be Google groups. Each occurrence of a principal counts towards these limits. For example, if thebindings grant 50 different roles touser:alice@example.com, and not to any other principal, then you can add another 1,450 principals to thebindings in thePolicy.

etag

string (bytes format)

etag is used for optimistic concurrency control as a way to help prevent simultaneous updates of a policy from overwriting each other. It is strongly suggested that systems make use of theetag in the read-modify-write cycle to perform policy updates in order to avoid race conditions: Anetag is returned in the response togetIamPolicy, and systems are expected to put that etag in the request tosetIamPolicy to ensure that their change will be applied to the same version of the policy.

Important: If you use IAM Conditions, you must include theetag field whenever you callsetIamPolicy. If you omit this field, then IAM allows you to overwrite a version3 policy with a version1 policy, and all of the conditions in the version3 policy are lost.

A base64-encoded string.

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Last updated 2025-06-13 UTC.