AWS CloudFormation Cheat Sheet

Updated 2026-04-28

AWS CloudFormation is Amazon's infrastructure as code (IaC) service for provisioning and managing AWS resources through declarative templates. Templates written in JSON or YAML define the desired state of resources, and CloudFormation handles creation, updates, and dependency management automatically. Unlike imperative scripting, CloudFormation's declarative approach lets you specify what infrastructure you need rather than how to build it, with built-in rollback on failure and drift detection to ensure deployed resources match the template definition. The AWS::LanguageExtensions transform (2022+), Git sync, Stack Refactoring, IaC Generator, and pre-deployment change set validation represent the latest capabilities that significantly improve the template authoring and deployment lifecycle.

What This Cheat Sheet Covers

This topic spans 18 focused tables and 127 indexed concepts. Below is a complete table-by-table outline of this topic, spanning foundational concepts through advanced details.

Table 1: Template SectionsTable 2: Resource AttributesTable 3: Intrinsic Functions — ReferencesTable 4: Intrinsic Functions — ConditionalsTable 5: Rule FunctionsTable 6: Pseudo ParametersTable 7: Parameter TypesTable 8: Dynamic ReferencesTable 9: Stack OperationsTable 10: Stack Policies and ProtectionTable 11: Nested, Cross-Stack, and Multi-Account FeaturesTable 12: Custom Resources and TransformsTable 13: Helper Scripts for EC2Table 14: Wait Conditions and SignalsTable 15: Template Validation and LintingTable 16: Registry and ExtensionsTable 17: Template FormatsTable 18: Stack States

Table 1: Template Sections

Every CloudFormation template is built from the same set of top-level blocks, and only Resources is actually required — the rest shape how a template takes input, makes decisions, and reports back. Getting comfortable with what each section is for is the foundation for reading or writing any template, so this is the right place to start.

Section	Example	Description
Resources	`Resources:` `MyBucket:` `Type: AWS::S3::Bucket`	• Required section — defines every AWS resource to create • each entry has a logical ID, Type, and Properties.
Parameters	`Parameters:` `InstanceType:` `Type: String` `Default: t3.micro`	• Input values passed at stack creation/update • supports validation constraints, defaults, and AWS-specific types for reusability.
Outputs	`Outputs:` `BucketName:` `Value: !Ref MyBucket` `Export:` `Name: MyBucketName`	• Values returned after stack creation • can be exported for cross-stack references via `!ImportValue`.
Mappings	`Mappings:` `RegionMap:` `us-east-1:` `AMI: ami-12345`	• Static key-value lookup tables for region-specific or environment-specific values • accessed with `Fn::FindInMap`.
Conditions	`Conditions:` `IsProd: !Equals [!Ref Env, prod]`	• Boolean logic evaluated at deployment time • used to conditionally create resources or set property values.

Table 1: Template Sections

Section	Example	Description
Resources	`Resources:` `MyBucket:` `Type: AWS::S3::Bucket`	• Required section — defines every AWS resource to create • each entry has a logical ID, Type, and Properties.
Parameters	`Parameters:` `InstanceType:` `Type: String` `Default: t3.micro`	• Input values passed at stack creation/update • supports validation constraints, defaults, and AWS-specific types for reusability.
Outputs	`Outputs:` `BucketName:` `Value: !Ref MyBucket` `Export:` `Name: MyBucketName`	• Values returned after stack creation • can be exported for cross-stack references via `!ImportValue`.
Mappings	`Mappings:` `RegionMap:` `us-east-1:` `AMI: ami-12345`	• Static key-value lookup tables for region-specific or environment-specific values • accessed with `Fn::FindInMap`.
Conditions	`Conditions:` `IsProd: !Equals [!Ref Env, prod]`	• Boolean logic evaluated at deployment time • used to conditionally create resources or set property values.