Manage GCP Identity-Aware Proxy IAM Permissions

The gcp:iap/webBackendServiceIamMember:WebBackendServiceIamMember resource, part of the Pulumi GCP provider, grants IAM permissions to individual members for IAP-protected backend services without affecting other role assignments. This guide focuses on three capabilities: single-member access grants, time-limited access with IAM Conditions, and multi-member role bindings.

Identity-Aware Proxy (IAP) controls access to backend services by verifying user identity before allowing requests through. This resource manages who can access specific backend services. The examples are intentionally small. Combine them with your own backend service infrastructure and organizational identity management.

Grant access to a single user

Most access control starts by granting IAP permissions to individual users without modifying existing role assignments.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const member = new gcp.iap.WebBackendServiceIamMember("member", {
    project: _default.project,
    webBackendService: _default.name,
    role: "roles/iap.httpsResourceAccessor",
    member: "user:jane@example.com",
});

import pulumi
import pulumi_gcp as gcp

member = gcp.iap.WebBackendServiceIamMember("member",
    project=default["project"],
    web_backend_service=default["name"],
    role="roles/iap.httpsResourceAccessor",
    member="user:jane@example.com")

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/iap"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := iap.NewWebBackendServiceIamMember(ctx, "member", &iap.WebBackendServiceIamMemberArgs{
			Project:           pulumi.Any(_default.Project),
			WebBackendService: pulumi.Any(_default.Name),
			Role:              pulumi.String("roles/iap.httpsResourceAccessor"),
			Member:            pulumi.String("user:jane@example.com"),
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var member = new Gcp.Iap.WebBackendServiceIamMember("member", new()
    {
        Project = @default.Project,
        WebBackendService = @default.Name,
        Role = "roles/iap.httpsResourceAccessor",
        Member = "user:jane@example.com",
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.iap.WebBackendServiceIamMember;
import com.pulumi.gcp.iap.WebBackendServiceIamMemberArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var member = new WebBackendServiceIamMember("member", WebBackendServiceIamMemberArgs.builder()
            .project(default_.project())
            .webBackendService(default_.name())
            .role("roles/iap.httpsResourceAccessor")
            .member("user:jane@example.com")
            .build());

    }
}

resources:
  member:
    type: gcp:iap:WebBackendServiceIamMember
    properties:
      project: ${default.project}
      webBackendService: ${default.name}
      role: roles/iap.httpsResourceAccessor
      member: user:jane@example.com

The member property specifies the identity receiving access, using formats like “user:email@example.com” for Google accounts or “serviceAccount:name@project.iam.gserviceaccount.com” for service accounts. The role property sets the permission level; “roles/iap.httpsResourceAccessor” allows HTTPS access to the backend service. The webBackendService property identifies which backend service to grant access to. This resource is non-authoritative, meaning it adds this member without removing other members who already have access.

Grant time-limited access with IAM Conditions

Organizations implementing temporary access use IAM Conditions to automatically expire permissions.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const member = new gcp.iap.WebBackendServiceIamMember("member", {
    project: _default.project,
    webBackendService: _default.name,
    role: "roles/iap.httpsResourceAccessor",
    member: "user:jane@example.com",
    condition: {
        title: "expires_after_2019_12_31",
        description: "Expiring at midnight of 2019-12-31",
        expression: "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
    },
});

import pulumi
import pulumi_gcp as gcp

member = gcp.iap.WebBackendServiceIamMember("member",
    project=default["project"],
    web_backend_service=default["name"],
    role="roles/iap.httpsResourceAccessor",
    member="user:jane@example.com",
    condition={
        "title": "expires_after_2019_12_31",
        "description": "Expiring at midnight of 2019-12-31",
        "expression": "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
    })

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/iap"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := iap.NewWebBackendServiceIamMember(ctx, "member", &iap.WebBackendServiceIamMemberArgs{
			Project:           pulumi.Any(_default.Project),
			WebBackendService: pulumi.Any(_default.Name),
			Role:              pulumi.String("roles/iap.httpsResourceAccessor"),
			Member:            pulumi.String("user:jane@example.com"),
			Condition: &iap.WebBackendServiceIamMemberConditionArgs{
				Title:       pulumi.String("expires_after_2019_12_31"),
				Description: pulumi.String("Expiring at midnight of 2019-12-31"),
				Expression:  pulumi.String("request.time < timestamp(\"2020-01-01T00:00:00Z\")"),
			},
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var member = new Gcp.Iap.WebBackendServiceIamMember("member", new()
    {
        Project = @default.Project,
        WebBackendService = @default.Name,
        Role = "roles/iap.httpsResourceAccessor",
        Member = "user:jane@example.com",
        Condition = new Gcp.Iap.Inputs.WebBackendServiceIamMemberConditionArgs
        {
            Title = "expires_after_2019_12_31",
            Description = "Expiring at midnight of 2019-12-31",
            Expression = "request.time < timestamp(\"2020-01-01T00:00:00Z\")",
        },
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.iap.WebBackendServiceIamMember;
import com.pulumi.gcp.iap.WebBackendServiceIamMemberArgs;
import com.pulumi.gcp.iap.inputs.WebBackendServiceIamMemberConditionArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var member = new WebBackendServiceIamMember("member", WebBackendServiceIamMemberArgs.builder()
            .project(default_.project())
            .webBackendService(default_.name())
            .role("roles/iap.httpsResourceAccessor")
            .member("user:jane@example.com")
            .condition(WebBackendServiceIamMemberConditionArgs.builder()
                .title("expires_after_2019_12_31")
                .description("Expiring at midnight of 2019-12-31")
                .expression("request.time < timestamp(\"2020-01-01T00:00:00Z\")")
                .build())
            .build());

    }
}

resources:
  member:
    type: gcp:iap:WebBackendServiceIamMember
    properties:
      project: ${default.project}
      webBackendService: ${default.name}
      role: roles/iap.httpsResourceAccessor
      member: user:jane@example.com
      condition:
        title: expires_after_2019_12_31
        description: Expiring at midnight of 2019-12-31
        expression: request.time < timestamp("2020-01-01T00:00:00Z")

The condition block adds temporal constraints to the permission grant. The expression property uses Common Expression Language (CEL) to define when access is valid; here, “request.time < timestamp(…)” expires access at midnight on 2020-01-01. The title and description properties document the condition’s purpose. IAM evaluates conditions on every request, automatically denying access once the timestamp passes without requiring manual revocation.

Grant a role to multiple users at once

When multiple users need identical permissions, binding a role to a list of members is more efficient than individual grants.

import * as pulumi from "@pulumi/pulumi";
import * as gcp from "@pulumi/gcp";

const binding = new gcp.iap.WebBackendServiceIamBinding("binding", {
    project: _default.project,
    webBackendService: _default.name,
    role: "roles/iap.httpsResourceAccessor",
    members: ["user:jane@example.com"],
});

import pulumi
import pulumi_gcp as gcp

binding = gcp.iap.WebBackendServiceIamBinding("binding",
    project=default["project"],
    web_backend_service=default["name"],
    role="roles/iap.httpsResourceAccessor",
    members=["user:jane@example.com"])

package main

import (
	"github.com/pulumi/pulumi-gcp/sdk/v9/go/gcp/iap"
	"github.com/pulumi/pulumi/sdk/v3/go/pulumi"
)

func main() {
	pulumi.Run(func(ctx *pulumi.Context) error {
		_, err := iap.NewWebBackendServiceIamBinding(ctx, "binding", &iap.WebBackendServiceIamBindingArgs{
			Project:           pulumi.Any(_default.Project),
			WebBackendService: pulumi.Any(_default.Name),
			Role:              pulumi.String("roles/iap.httpsResourceAccessor"),
			Members: pulumi.StringArray{
				pulumi.String("user:jane@example.com"),
			},
		})
		if err != nil {
			return err
		}
		return nil
	})
}

using System.Collections.Generic;
using System.Linq;
using Pulumi;
using Gcp = Pulumi.Gcp;

return await Deployment.RunAsync(() => 
{
    var binding = new Gcp.Iap.WebBackendServiceIamBinding("binding", new()
    {
        Project = @default.Project,
        WebBackendService = @default.Name,
        Role = "roles/iap.httpsResourceAccessor",
        Members = new[]
        {
            "user:jane@example.com",
        },
    });

});

package generated_program;

import com.pulumi.Context;
import com.pulumi.Pulumi;
import com.pulumi.core.Output;
import com.pulumi.gcp.iap.WebBackendServiceIamBinding;
import com.pulumi.gcp.iap.WebBackendServiceIamBindingArgs;
import java.util.List;
import java.util.ArrayList;
import java.util.Map;
import java.io.File;
import java.nio.file.Files;
import java.nio.file.Paths;

public class App {
    public static void main(String[] args) {
        Pulumi.run(App::stack);
    }

    public static void stack(Context ctx) {
        var binding = new WebBackendServiceIamBinding("binding", WebBackendServiceIamBindingArgs.builder()
            .project(default_.project())
            .webBackendService(default_.name())
            .role("roles/iap.httpsResourceAccessor")
            .members("user:jane@example.com")
            .build());

    }
}

resources:
  binding:
    type: gcp:iap:WebBackendServiceIamBinding
    properties:
      project: ${default.project}
      webBackendService: ${default.name}
      role: roles/iap.httpsResourceAccessor
      members:
        - user:jane@example.com

The members property accepts an array of identities, all receiving the same role. This uses WebBackendServiceIamBinding instead of WebBackendServiceIamMember; the binding resource is authoritative for the specified role, meaning it replaces any existing members for that role. Use binding when you want to define the complete member list for a role; use member when you want to add individuals without affecting others.

Beyond these examples

These snippets focus on specific IAM member features: single-member and multi-member grants, and IAM Conditions for time-based access. They’re intentionally minimal rather than full access control policies.

The examples reference pre-existing infrastructure such as IAP-protected backend services and GCP projects with IAP enabled. They focus on granting permissions rather than provisioning the backend services themselves.

To keep things focused, common IAM patterns are omitted, including:

Policy-level management (WebBackendServiceIamPolicy)
Service account and group identities
Custom role definitions
Federated identity principals

These omissions are intentional: the goal is to illustrate how each IAM grant is wired, not provide drop-in access control modules. See the WebBackendServiceIamMember resource reference for all available configuration options.

Let's manage GCP Identity-Aware Proxy IAM Permissions

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Frequently Asked Questions

Resource Selection & Conflicts

Which IAM resource should I use to manage access to my backend service?

Choose based on your needs: WebBackendServiceIamPolicy for full policy control (replaces existing policy), WebBackendServiceIamBinding for managing all members of a specific role, or WebBackendServiceIamMember for adding individual members without affecting others.

Can I use multiple IAM resources together?

WebBackendServiceIamPolicy cannot be used with WebBackendServiceIamBinding or WebBackendServiceIamMember, as they’ll conflict over policy management. However, WebBackendServiceIamBinding and WebBackendServiceIamMember can coexist if they manage different roles.

IAM Configuration

What member identity formats are supported?

You can use: allUsers, allAuthenticatedUsers, user:{email}, serviceAccount:{email}, group:{email}, domain:{domain}, projectOwner/Editor/Viewer:{projectid}, or federated identities like principal://iam.googleapis.com/....

How do I specify a custom IAM role?

Custom roles must use the format [projects|organizations]/{parent-name}/roles/{role-name}. For example: projects/my-project/roles/customRole.

How do I add time-based or conditional access?

Use the condition property with title, description, and expression fields. For example, to expire access: expression: "request.time < timestamp(\"2020-01-01T00:00:00Z\")".

What are the limitations of IAM Conditions?

IAM Conditions are supported but have known limitations. Review the GCP documentation on IAM Conditions limitations if you encounter issues.

Resource Properties & Immutability

What properties can't be changed after creation?

All properties are immutable: member, role, condition, webBackendService, and project. Changes require recreating the resource.

Using a different cloud?

Explore iam guides for other cloud providers:

AWS Guides Azure Guides