What is Terraform's provider development and custom providers?

Custom Terraform providers let you manage any API as Terraform resources. Providers are written in Go using the Terraform Plugin Framework (current) or the legacy Plugin SDK. A provider implements: Provider schema: configuration (credentials, endpoints). Resources: CRUD operations (Create, Read, Update, Delete) as Go functions that call the target API. Data sources: Read-only operations. The framework uses resource.Schema to define attribute types and validation. Publish to the Terraform Registry with a GitHub release and GPG-signed binary. Use cases: internal company APIs, third-party SaaS tools without community providers, on-premises systems. The CDKTF (CDK for Terraform) is an alternative — write providers and configurations in TypeScript, Python, Java, or C#, compiled to HCL JSON. The terraform-provider-scaffolding-framework template is the starting point for new providers.