This extension help you author AWS CloudFormation templates with ease.
It uses JSON schema validation features of VSCode to validate your template files against a schema for AWS CloudFormation (currently uses cloudformation-jsonschema)
Capabilities
Supports authoring of CloudFormation templates in JSON
Highlights errors with a helpful error message (in the "Problems" pane, and as a pop-up message visible on hover)
Highlights errors when JSON is malformed
Highlights errors for required elements, required properties, invalid document structure, etc.
Suggests top-level elements (such as Parameters, Resources, etc.)
Auto-completes known elements (such as AWSTemplateFormatVersion)
Auto-completes structure of elements, intrinsic functions, etc.
Suggests supported properties for elements in Parameters, Resources, Outputs, etc.
Suggests supported Type information for Parameters and Resources
Suggests required and supported properties for each resource (by Type)