Pulumi takes the same approach as AWS CDK — use a real programming language to define infrastructure — but without the CloudFormation layer underneath. Pulumi talks directly to cloud APIs, maintains its own state, and supports multiple clouds from a single codebase.

Languages: TypeScript, Python, Go, Java, C#, and YAML. Same language across all supported clouds.

How it works

Write infrastructure as code in your language of choice. Pulumi runs the program, builds a desired-state graph, diffs against current state, and makes the API calls to converge.

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

const bucket = new aws.s3.Bucket("assets", {
    versioning: { enabled: true },
    tags: { Environment: "prod" },
});

export const bucketName = bucket.bucket;

pulumi preview   # show planned changes
pulumi up        # apply
pulumi destroy   # tear down

State

Pulumi manages state like Terraform — a backend stores what resources exist and their current configuration. Options:

• Pulumi Cloud — hosted, free tier available, adds secrets management and team features
• S3 / GCS / Azure Blob — self-managed, same pattern as Terraform’s remote backend

vs Terraform

The core tradeoff: Pulumi gives you a real programming language (real loops, real functions, real tests) at the cost of a smaller ecosystem and less community tooling than Terraform. HCL is a constraint but also a simplicity — Terraform configurations are declarative and readable without needing to understand the language runtime.

Pulumi is the better choice when infrastructure logic is genuinely complex enough to benefit from a real language. For straightforward cloud resources, Terraform’s declarative HCL is often simpler to read and maintain.

vs AWS CDK

Both use real languages. The difference: CDK generates CloudFormation and inherits all of CloudFormation’s limitations (see the CDK page). Pulumi talks directly to cloud APIs, which means better drift visibility, faster deploys, and support outside AWS.

Testing

Because infrastructure is code, it tests like code:

• Unit tests with Jest (TypeScript), pytest (Python), or Go test — test the resource graph without deploying
• Integration tests that deploy to an isolated stack and assert against live infrastructure

OpenTofu / Terraform note

After HashiCorp changed Terraform’s licence to BSL in 2023, the community forked it as OpenTofu. If the licence change matters to your organisation, OpenTofu is a drop-in replacement. Pulumi was not affected.

Only explored in POC and lab contexts, not production. The honest take: Pulumi feels like the Gradle of IaC. The real-language argument is compelling in theory — proper loops, functions, tests, abstractions — but in practice it is easy to get wrong, and HCL’s constraint is also its strength. A Terraform configuration is readable by anyone; a Pulumi TypeScript codebase requires understanding the language runtime and the person who wrote it.

The cases where Pulumi wins: complex infrastructure logic that genuinely benefits from a real language, or teams already deep in a single language who want infrastructure to live alongside application code. For standard cloud infrastructure, Terraform is the lower-friction choice.