Pulumi vs CDK

Pulumi and AWS CDK both let you define infrastructure using general-purpose programming languages, but they take different approaches. CDK synthesizes to CloudFormation and is AWS-focused. Pulumi has its own engine and supports multiple cloud providers.

The Underlying Engine

CDK — CloudFormation Under the Hood

CDK code compiles into CloudFormation templates via a process called synthesis. This means you get all of CloudFormation's benefits: automatic rollback, drift detection, stack management, and no state file to manage. The downside is CloudFormation's limitations: 500-resource stack limit, slow deployments for large stacks, and sometimes confusing error messages from the synthesis layer.

Pulumi — Native Engine

Pulumi has its own deployment engine that communicates directly with cloud provider APIs. There is no intermediate template format. This means faster deployments, no resource limits per stack, and more direct error messages. The tradeoff is that you need to manage state (via Pulumi Cloud or self-hosted backends) and there is no automatic rollback.

Abstraction Levels

CDK's L1/L2/L3 construct model is one of its strongest features. L1 constructs map 1:1 to CloudFormation resources. L2 constructs add sensible defaults and convenience methods (e.g., bucket.grantRead(lambda) handles IAM permissions automatically). L3 constructs are opinionated patterns combining multiple resources. This layered abstraction significantly reduces boilerplate for AWS resources.

Pulumi has component resources for creating abstractions, but its standard library is more low-level than CDK's L2 constructs. Pulumi's multi-cloud support means it cannot provide the same depth of provider-specific convenience.

Multi-Cloud

If you need to manage infrastructure across AWS, GCP, Azure, and Kubernetes, Pulumi is the clear choice. CDK for Terraform exists but adds complexity. If you are AWS-only, CDK provides a richer, more integrated experience.

For IaC patterns, explore our concepts and system design interview guide. See interview questions and pricing.