Shieldly vs Cloud Custodian: PR-Time IAM Fixes vs Live-Account Governance

Cloud Custodian is an open-source governance-as-code engine. You write YAML policies that query live resources and take action — tag, notify, stop, or delete — on a schedule or in response to events, which makes it strong for ongoing cost and compliance enforcement across an account. Shieldly is an AI-Powered analyzer that explains why a specific AWS IAM, resource policy, or CloudFormation template is risky and hands back the tightened version — free, no signup, before the resource ever exists. One governs what is already running; the other reviews the policy at authoring time.

What Cloud Custodian Is Great At

Continuous, automated governance of live resources. Custodian shines at sweeping an account for resources that violate a rule and acting on them — enforcing tagging standards, stopping idle instances, or remediating drift — all defined as version-controlled YAML and run on a schedule or via event triggers. If you need ongoing enforcement and remediation against deployed infrastructure, that is its home turf.

Where Shieldly Fits

Custodian acts after a resource exists and a rule matches. Shieldly reviews the policy before it ships and explains the why in plain English, plus the corrected policy, for the engineer in the pull request. It also reasons about multi-step privilege-escalation chains inside a single policy — for example a trust policy that lets an unintended principal assume a powerful role — which a per-resource enforcement rule does not express. Paste a policy into the web app, or run the @shieldly/cli, VS Code extension, GitHub Action, or @shieldly/cdk-guard construct.

Side by Side

Use Both

They sit at different stages and reinforce each other.

• Use Cloud Custodian to continuously govern and remediate live resources against your org's rules.
• Use Shieldly at PR time to explain and fix risky IAM / CloudFormation before it becomes a deployed resource Custodian has to act on.
• When a Custodian rule flags an over-permissioned role, paste the policy into Shieldly for the reason and a tightened version.

AWS and CloudFormation are trademarks of Amazon.com, Inc. Cloud Custodian is a project of its respective owner. Shieldly is not affiliated with or endorsed by either. Comparisons reflect public information as of 2026 and general product categories.

Amazon Web Services (AWS) is a trademark of Amazon.com, Inc. Shieldly is not affiliated with, endorsed by, or sponsored by Amazon Web Services.