Inline Policy vs Managed Policy in AWS: Key Differences and Usage

In AWS, a managed policy is a standalone policy that you can attach to multiple users, groups, or roles, while an inline policy is embedded directly into a single user, group, or role. Managed policies are reusable and easier to manage, whereas inline policies are tightly coupled to one identity and deleted if that identity is removed.

Quick Comparison

Here is a quick side-by-side comparison of inline policies and managed policies in AWS IAM.

Factor	Inline Policy	Managed Policy
Definition	Policy embedded directly into one user, group, or role	Standalone policy that can be attached to multiple identities
Reusability	No, tied to a single identity	Yes, reusable across many identities
Management	Managed within the identity	Managed independently in IAM
Deletion Impact	Deleted if the identity is deleted	Remains even if detached from identities
Use Case	Specific, one-off permissions	Common, shared permissions
Versioning & Updates	No versioning, update affects only one identity	Supports versioning and centralized updates

Key Differences

Inline policies are policies that exist only as part of a single IAM user, group, or role. They are tightly bound to that identity and cannot be reused elsewhere. If you delete the identity, the inline policy is also deleted. This makes inline policies useful for very specific permissions that should not be shared.

On the other hand, managed policies are standalone IAM policies that exist independently of any user, group, or role. You can attach the same managed policy to multiple identities, making it easier to manage permissions consistently across your AWS environment. Managed policies support versioning, so you can update permissions centrally and have those changes apply to all attached identities.

Managed policies are generally preferred for common permission sets because they simplify management and auditing. Inline policies are best for unique, tightly scoped permissions that should not be reused or shared.

Code Comparison

Here is an example of an inline policy attached directly to an IAM user to allow listing S3 buckets.

json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:ListAllMyBuckets",
      "Resource": "*"
    }
  ]
}

Output

This policy allows the user to list all S3 buckets in the AWS account.

Managed Policy Equivalent

The same permission as a managed policy JSON document that can be attached to multiple users, groups, or roles.

json

{
  "Version": "2012-10-17",
  "Statement": [
    {
      "Effect": "Allow",
      "Action": "s3:ListAllMyBuckets",
      "Resource": "*"
    }
  ]
}

Output

This managed policy can be attached to any number of identities to allow listing all S3 buckets.

When to Use Which

Choose managed policies when you want to apply the same permissions to multiple users, groups, or roles and want easier management and updates. Managed policies are best for common or shared permissions.

Choose inline policies when you need very specific permissions for a single identity that should not be reused or shared. Inline policies are useful for one-off, tightly scoped access control.

Key Takeaways

Managed policies are reusable and easier to manage across multiple identities.

Inline policies are embedded in a single identity and deleted with it.

Use managed policies for common permissions and inline policies for unique cases.

Managed policies support versioning and centralized updates.

Inline policies provide tight, one-off permission control.