Can I automatically enable APIs when using GCP cloud with terraform?

There is a Terraform resource definition called "google_project_service" that allows one to enable a service (API). This is documented at google_project_service.

An example of usage appears to be:

resource "google_project_service" "project" {
  project = "your-project-id"
  service = "iam.googleapis.com"
}

instead of using count as suggested by @pradeep you may also loop over the services in question:

variable "gcp_service_list" {
  description ="The list of apis necessary for the project"
  type = list(string)
  default = [
    "cloudresourcemanager.googleapis.com",
    "serviceusage.googleapis.com"
  ]
}

resource "google_project_service" "gcp_services" {
  for_each = toset(var.gcp_service_list)
  project = "your-project-id"
  service = each.key
}

Yes , you can use google_project_service resource to enable one API at a time. You can use count or other loop methods to enable multiple APIs. You would need project editor/owner role to do this.

# Enable services in newly created GCP Project.
resource "google_project_service" "gcp_services" {
  count   = length(var.gcp_service_list)
  project = google_project.demo_project.project_id
  service = var.gcp_service_list[count.index]

  disable_dependent_services = true
}

You can find the complete example here.

For those reading this in 2022, enabling serviceusage and cloudresourcesmanager automatically from Terraform doesn't work as enabling those APIs through the API has a dependency on them being already enabled...

The solution is to do it through the gcloud command line:

# Use `gcloud` to enable:
# - serviceusage.googleapis.com
# - cloudresourcemanager.googleapis.com
resource "null_resource" "enable_service_usage_api" {
  provisioner "local-exec" {
    command = "gcloud services enable serviceusage.googleapis.com cloudresourcemanager.googleapis.com --project ${var.project_id}"
  }

  depends_on = [google_project.project]
}

# Wait for the new configuration to propagate
# (might be redundant)
resource "time_sleep" "wait_project_init" {
  create_duration = "60s"

  depends_on = [null_resource.enable_service_usage_api]
}

More details on https://medium.com/rockedscience/how-to-fully-automate-the-deployment-of-google-cloud-platform-projects-with-terraform-16c33f1fb31f