Ask HN: CDK vs. Terraform – which one do you prefer and why?

Depends on the project.

Terraform is for when you are doing large projects in company, and want to have additional management features that CDK doesn't have.

On the flip side, for personal projects, you can get away with using boto3 library with the api it provides to create infrastructure, considering infrastructure probably won't change much, and its free. You pretty much just have to write a little wrapper to create the resource if it doesn't exist, then modify its attributes whether its just been created or if it already exists.

CDK, and pure cloudformation, and others are somewhere in between

Terraform, because the tooling around it is just much better for things like drift detection, showing planned changes, pipelines, etc.

That isn't vendor agnostic.

Our team uses CDK or CFN for building aws "platform level" infra (ie is go to for infra roles who build / maintain kube clusters or account level stuff), but terraform as the iac for devs who manage their own app-level resources eg rds, queues, hsms etc.

The rationale is that CDK/CFN seems to work more reliably "at scale" for commonly used stacks due to low drama rollbacks etc. Roles that are primarily infra tend to not mind using aws focused tooling.

For devs, the documentation and usability of terraform is just better, plus the wide range of 3rd party integrations is handy. While it can be fiddly / not as scalable it's also a lot easier to adopt resources or refactor stuff which you tend to need more with "precious" long lived app resources.

Pulumi.