diff --git a/README.md b/README.md
index 62cef07..d3566b0 100644
--- a/README.md
+++ b/README.md
@@ -151,59 +151,7 @@ The _Tailwind CSS IntelliSense_ extension is a must-have companion in all projec
 
 ## Configuration
 
-The application is configured using Environment Variables. Because single-page applications are static, environment variable values are injected into the application during the build. The environment variables may be sourced from the environment or `.env` files as described in the [Vite documentation](https://vitejs.dev/guide/env-and-mode.html).
-
-### `.env` files
-
-> **NOTE:** Because they may contain sensitive information, `.env` files are not committed to the repository.
-
-After project installation and before running the application locally, create the following `.env` files in the project base directory. Copy the `.env.example` file to get started. Learn more in the official [Vite guide for environment variables and modes](https://vitejs.dev/guide/env-and-mode.html).
-
-#### `.env.local`
-
-The `.env.local` configuration file provides the configuration values when the application is started on a developer's local machine.
-
-```
-# Provided by Pipeline (Simulated)
-VITE_BUILD_DATE=1970-01-01
-VITE_BUILD_TIME=00:00:00
-VITE_BUILD_TS=1970-01-01T00:00:00+0000
-VITE_BUILD_COMMIT_SHA=local
-VITE_BUILD_ENV_CODE=local
-VITE_BUILD_WORKFLOW_NAME=local
-VITE_BUILD_WORKFLOW_RUN_NUMBER=1
-VITE_BUILD_WORKFLOW_RUN_ATTEMPT=1
-
-# API Configuration
-VITE_BASE_URL_API=https://jsonplaceholder.typicode.com
-
-# Toasts Configuration
-VITE_TOAST_AUTO_DISMISS_MILLIS=5000
-```
-
-#### `.env.test.local`
-
-The `.env.test.local` configuration file provides configuration values used when unit tests are executed on a developer's local machine.
-
-> **NOTE:** Use the same values when running tests in a CI/CD pipeline.
-
-```
-# Provided by Pipeline (Simulated)
-VITE_BUILD_DATE=1970-01-01
-VITE_BUILD_TIME=00:00:00
-VITE_BUILD_TS=1970-01-01T00:00:00+0000
-VITE_BUILD_COMMIT_SHA=test
-VITE_BUILD_ENV_CODE=test
-VITE_BUILD_WORKFLOW_NAME=test
-VITE_BUILD_WORKFLOW_RUN_NUMBER=1
-VITE_BUILD_WORKFLOW_RUN_ATTEMPT=1
-
-# API Configuration
-VITE_BASE_URL_API=https://jsonplaceholder.typicode.com
-
-# Toasts Configuration
-VITE_TOAST_AUTO_DISMISS_MILLIS=1500
-```
+See the [Configuration Guide](./docs/CONFIGURATION_GUIDE.md) in the [project docs](./docs/README.md) for detailed information about application and infrastructure configuration.
 
 ## Available Scripts
 
diff --git a/docs/CONFIGURATION_GUIDE.md b/docs/CONFIGURATION_GUIDE.md
new file mode 100644
index 0000000..f67a1d5
--- /dev/null
+++ b/docs/CONFIGURATION_GUIDE.md
@@ -0,0 +1,493 @@
+# Configuration Guide
+
+This guide provides comprehensive information about configuring the React Starter application and its AWS CDK infrastructure.
+
+## Application Configuration
+
+The React application configuration is managed through environment variables prefixed with `VITE_`. These variables are available at build time and runtime in your React components.
+
+### Environment Variables
+
+The following environment variables are available for configuring the React application:
+
+| Variable                          | Type   | Description                                          | Default | Required |
+| --------------------------------- | ------ | ---------------------------------------------------- | ------- | -------- |
+| `VITE_BASE_URL_API`               | string | Base URL for API requests                            | -       | Yes      |
+| `VITE_TOAST_AUTO_DISMISS_MILLIS`  | number | Auto-dismiss duration for toast notifications (ms)   | `5000`  | No       |
+| `VITE_BUILD_DATE`                 | string | Build date (YYYY-MM-DD format)                       | -       | No       |
+| `VITE_BUILD_TIME`                 | string | Build time (HH:MM:SS format)                         | -       | No       |
+| `VITE_BUILD_TS`                   | string | Build timestamp (ISO 8601 format)                    | -       | No       |
+| `VITE_BUILD_COMMIT_SHA`           | string | Git commit SHA of the build                          | -       | No       |
+| `VITE_BUILD_ENV_CODE`             | string | Environment code (e.g., `local`, `dev`, `qa`, `prd`) | -       | No       |
+| `VITE_BUILD_WORKFLOW_NAME`        | string | CI/CD workflow name                                  | -       | No       |
+| `VITE_BUILD_WORKFLOW_RUN_NUMBER`  | string | CI/CD workflow run number                            | -       | No       |
+| `VITE_BUILD_WORKFLOW_RUN_ATTEMPT` | string | CI/CD workflow run attempt number                    | -       | No       |
+
+### Setup
+
+1. **Copy the example configuration file:**
+
+   ```bash
+   cp .env.example .env
+   ```
+
+2. **Update variables for your environment:**
+
+   ```env
+   VITE_BASE_URL_API=https://your-api.example.com
+   VITE_TOAST_AUTO_DISMISS_MILLIS=5000
+   ```
+
+3. **Build information** (typically set by CI/CD pipeline):
+   ```env
+   VITE_BUILD_DATE=2026-02-10
+   VITE_BUILD_TIME=14:30:00
+   VITE_BUILD_TS=2026-02-10T14:30:00+0000
+   VITE_BUILD_COMMIT_SHA=abc123def456
+   VITE_BUILD_ENV_CODE=dev
+   VITE_BUILD_WORKFLOW_NAME=Build
+   VITE_BUILD_WORKFLOW_RUN_NUMBER=42
+   VITE_BUILD_WORKFLOW_RUN_ATTEMPT=1
+   ```
+
+### Accessing Configuration
+
+Application configuration values are accessible directly in your React components since Vite automatically injects them:
+
+```typescript
+// API base URL
+const apiUrl = import.meta.env.VITE_BASE_URL_API;
+
+// Toast settings
+const toastDuration = import.meta.env.VITE_TOAST_AUTO_DISMISS_MILLIS;
+
+// Build information
+const buildDate = import.meta.env.VITE_BUILD_DATE;
+const buildCommit = import.meta.env.VITE_BUILD_COMMIT_SHA;
+```
+
+### Local Development
+
+For local development, create a `.env` file in the root directory with local values:
+
+```env
+VITE_BASE_URL_API=http://localhost:3000
+VITE_TOAST_AUTO_DISMISS_MILLIS=5000
+VITE_BUILD_DATE=1970-01-01
+VITE_BUILD_TIME=00:00:00
+VITE_BUILD_TS=1970-01-01T00:00:00+0000
+VITE_BUILD_COMMIT_SHA=local
+VITE_BUILD_ENV_CODE=local
+VITE_BUILD_WORKFLOW_NAME=local
+VITE_BUILD_WORKFLOW_RUN_NUMBER=1
+VITE_BUILD_WORKFLOW_RUN_ATTEMPT=1
+```
+
+### Unit Testing
+
+For running unit tests, create a `.env.test.local` file in the root directory with values optimized for the test environment. This configuration is used by Vitest when running unit tests.
+
+1. **Copy the example configuration file:**
+
+   ```bash
+   cp .env.example .env.test.local
+   ```
+
+2. **Update with test-specific values:**
+
+   ```env
+   # Provided by Pipeline (Simulated)
+   VITE_BUILD_DATE=1970-01-01
+   VITE_BUILD_TIME=00:00:00
+   VITE_BUILD_TS=1970-01-01T00:00:00+0000
+   VITE_BUILD_COMMIT_SHA=test
+   VITE_BUILD_ENV_CODE=test
+   VITE_BUILD_WORKFLOW_NAME=test
+   VITE_BUILD_WORKFLOW_RUN_NUMBER=1
+   VITE_BUILD_WORKFLOW_RUN_ATTEMPT=1
+
+   # API Configuration
+   # Use JSONPlaceholder for mock API testing
+   VITE_BASE_URL_API=https://jsonplaceholder.typicode.com
+
+   # Toasts Configuration
+   # Use shorter duration in tests for faster test execution
+   VITE_TOAST_AUTO_DISMISS_MILLIS=1500
+   ```
+
+#### Test Configuration Notes
+
+- **API Base URL**: Uses [JSONPlaceholder](https://jsonplaceholder.typicode.com/) - a free fake REST API for testing. In actual test environments, API calls are typically mocked using MSW (Mock Service Worker).
+- **Toast Duration**: Reduced to 1500ms for faster test execution while still allowing time for async operations.
+- **Build Information**: All build-related variables are set to static test values, ensuring consistent snapshots and reproducible test results.
+- **Environment Code**: Set to `test` to distinguish test runs from development and production.
+
+#### Usage with MSW
+
+The test configuration works seamlessly with [MSW](https://mswjs.io/) (Mock Service Worker), which intercepts HTTP requests in tests. The `VITE_BASE_URL_API` can point to a test server, and MSW handlers will intercept and mock responses:
+
+```typescript
+// Example MSW handler in tests
+import { http, HttpResponse } from 'msw';
+import { setupServer } from 'msw/node';
+
+const server = setupServer(
+  http.get('https://jsonplaceholder.typicode.com/users', () => {
+    return HttpResponse.json([{ id: 1, name: 'Test User' }]);
+  }),
+);
+
+beforeAll(() => server.listen());
+afterEach(() => server.resetHandlers());
+afterAll(() => server.close());
+```
+
+---
+
+## Infrastructure Configuration
+
+The infrastructure configuration is managed through environment variables prefixed with `CDK_`. These variables control how AWS resources are provisioned and deployed using the AWS CDK.
+
+### Environment Variables
+
+The following environment variables are available for configuring the infrastructure:
+
+| Variable                         | Type   | Description                                                                   | Default                    | Required |
+| -------------------------------- | ------ | ----------------------------------------------------------------------------- | -------------------------- | -------- |
+| `CDK_APP_NAME`                   | string | Application name used in resource naming and tagging                          | `react-starter`            | No       |
+| `CDK_ENV`                        | enum   | Deployment environment: `dev`, `qa`, `prd`                                    | -                          | Yes      |
+| `CDK_ACCOUNT`                    | string | AWS account ID for deployment                                                 | Auto-detected from AWS CLI | No       |
+| `CDK_REGION`                     | string | AWS region for deployment (e.g., `us-east-1`)                                 | Auto-detected from AWS CLI | No       |
+| `CDK_OU`                         | string | Organizational Unit for resource tagging                                      | `unknown`                  | No       |
+| `CDK_OWNER`                      | string | Owner tag for resource tracking                                               | `unknown`                  | No       |
+| `CDK_ASSET_PATH`                 | string | Path to application build artifacts (relative to infrastructure directory)    | `../dist`                  | No       |
+| `CDK_DOMAIN_NAME`                | string | Custom domain name for the application CDN (e.g., `app.example.com`)          | -                          | No       |
+| `CDK_CERTIFICATE_ARN`            | string | ACM certificate ARN for custom domain (must be in `us-east-1` for CloudFront) | -                          | No       |
+| `CDK_HOSTED_ZONE_ID`             | string | Route53 hosted zone ID for DNS records                                        | -                          | No       |
+| `CDK_HOSTED_ZONE_NAME`           | string | Route53 hosted zone name (e.g., `example.com`)                                | -                          | No       |
+| `CDK_STORYBOOK_ASSET_PATH`       | string | Path to Storybook build artifacts (relative to infrastructure directory)      | `../storybook-static`      | No       |
+| `CDK_STORYBOOK_DOMAIN_NAME`      | string | Custom domain name for Storybook CDN                                          | -                          | No       |
+| `CDK_STORYBOOK_CERTIFICATE_ARN`  | string | ACM certificate ARN for Storybook custom domain                               | -                          | No       |
+| `CDK_STORYBOOK_HOSTED_ZONE_ID`   | string | Route53 hosted zone ID for Storybook DNS records                              | -                          | No       |
+| `CDK_STORYBOOK_HOSTED_ZONE_NAME` | string | Route53 hosted zone name for Storybook                                        | -                          | No       |
+
+### Setup
+
+1. **Navigate to the infrastructure directory:**
+
+   ```bash
+   cd infrastructure
+   ```
+
+2. **Copy the example configuration file:**
+
+   ```bash
+   cp .env.example .env
+   ```
+
+3. **Update variables for your environment:**
+   ```env
+   CDK_ENV=dev
+   CDK_APP_NAME=react-starter
+   CDK_ACCOUNT=123456789012
+   CDK_REGION=us-east-1
+   CDK_OU=software-engineering
+   CDK_OWNER=your-team
+   ```
+
+### Usage
+
+Infrastructure configuration is loaded and validated through the `getConfig()` function in `infrastructure/utils/config.ts`:
+
+```typescript
+import { getConfig, getTags, getEnvironmentConfig } from './utils/config';
+
+const config = getConfig();
+const tags = getTags(config);
+const envConfig = getEnvironmentConfig(config);
+
+console.log(`Environment: ${config.CDK_ENV}`);
+console.log(`App name: ${config.CDK_APP_NAME}`);
+console.log(`Tags:`, tags);
+```
+
+### Configuration Files
+
+Infrastructure configuration can be provided through:
+
+1. **Environment variables** - Set directly in your shell or CI/CD pipeline (highest priority)
+2. **.env file** - Create a `.env` file in the `infrastructure/` directory for local development
+3. **Default values** - Specified in the Zod schema (lowest priority)
+
+### Resource Tagging
+
+All AWS resources created by the CDK are automatically tagged with the following tags:
+
+| Tag     | Description                      | Source         |
+| ------- | -------------------------------- | -------------- |
+| `App`   | Application name                 | `CDK_APP_NAME` |
+| `Env`   | Environment (`dev`, `qa`, `prd`) | `CDK_ENV`      |
+| `OU`    | Organizational Unit              | `CDK_OU`       |
+| `Owner` | Team or individual responsible   | `CDK_OWNER`    |
+
+These tags are used for cost allocation, resource management, and identifying resources in AWS.
+
+### Example Configurations
+
+#### Development Environment
+
+Create `infrastructure/.env` for development deployment:
+
+```env
+###############################################
+## Development Environment Configuration
+###############################################
+
+CDK_APP_NAME=react-starter
+CDK_ENV=dev
+CDK_ACCOUNT=123456789012
+CDK_REGION=us-east-1
+
+### Resource Tagging ###
+CDK_OU=software-engineering
+CDK_OWNER=frontend-team
+
+### CDN Configuration ###
+CDK_ASSET_PATH=../dist
+CDK_DOMAIN_NAME=react-starter.dev.example.com
+CDK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+CDK_HOSTED_ZONE_ID=Z1234567890ABC
+CDK_HOSTED_ZONE_NAME=dev.example.com
+
+### Storybook CDN Configuration ###
+CDK_STORYBOOK_ASSET_PATH=../storybook-static
+CDK_STORYBOOK_DOMAIN_NAME=react-starter-storybook.dev.example.com
+CDK_STORYBOOK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+CDK_STORYBOOK_HOSTED_ZONE_ID=Z1234567890ABC
+CDK_STORYBOOK_HOSTED_ZONE_NAME=dev.example.com
+```
+
+#### QA Environment
+
+```env
+###############################################
+## QA Environment Configuration
+###############################################
+
+CDK_APP_NAME=react-starter
+CDK_ENV=qa
+CDK_ACCOUNT=123456789012
+CDK_REGION=us-east-1
+
+CDK_OU=software-engineering
+CDK_OWNER=frontend-team
+
+CDK_ASSET_PATH=../dist
+CDK_DOMAIN_NAME=react-starter.qa.example.com
+CDK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+CDK_HOSTED_ZONE_ID=Z1234567890ABC
+CDK_HOSTED_ZONE_NAME=qa.example.com
+
+CDK_STORYBOOK_ASSET_PATH=../storybook-static
+CDK_STORYBOOK_DOMAIN_NAME=react-starter-storybook.qa.example.com
+CDK_STORYBOOK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+CDK_STORYBOOK_HOSTED_ZONE_ID=Z1234567890ABC
+CDK_STORYBOOK_HOSTED_ZONE_NAME=qa.example.com
+```
+
+#### Production Environment
+
+```env
+###############################################
+## Production Environment Configuration
+###############################################
+
+CDK_APP_NAME=react-starter
+CDK_ENV=prd
+CDK_ACCOUNT=123456789012
+CDK_REGION=us-east-1
+
+CDK_OU=software-engineering
+CDK_OWNER=frontend-team
+
+CDK_ASSET_PATH=../dist
+CDK_DOMAIN_NAME=react-starter.example.com
+CDK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+CDK_HOSTED_ZONE_ID=Z1234567890ABC
+CDK_HOSTED_ZONE_NAME=example.com
+
+CDK_STORYBOOK_ASSET_PATH=../storybook-static
+CDK_STORYBOOK_DOMAIN_NAME=react-starter-storybook.example.com
+CDK_STORYBOOK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx
+CDK_STORYBOOK_HOSTED_ZONE_ID=Z1234567890ABC
+CDK_STORYBOOK_HOSTED_ZONE_NAME=example.com
+```
+
+### AWS Account and Region
+
+The CDK uses the following precedence for account and region:
+
+1. **Explicit CDK variables** (highest priority)
+   - `CDK_ACCOUNT` - AWS account ID
+   - `CDK_REGION` - AWS region
+
+2. **AWS CDK environment defaults**
+   - `CDK_DEFAULT_ACCOUNT` - Auto-detected from AWS credentials
+   - `CDK_DEFAULT_REGION` - Auto-detected from AWS profile
+
+3. **AWS CLI configuration**
+   - Uses the configured AWS profile and region
+
+If neither explicit CDK variables nor CDK_DEFAULT environment variables are set, the CDK will fail with an error requesting explicit account and region configuration.
+
+### Custom Domain and SSL/TLS
+
+To use a custom domain for your application:
+
+1. **Create an ACM certificate** in `us-east-1` (required for CloudFront):
+
+   ```bash
+   aws acm request-certificate \
+     --domain-name react-starter.example.com \
+     --region us-east-1
+   ```
+
+2. **Verify the certificate** in the ACM console
+
+3. **Configure in `.env`:**
+
+   ```env
+   CDK_DOMAIN_NAME=react-starter.example.com
+   CDK_CERTIFICATE_ARN=arn:aws:acm:us-east-1:123456789012:certificate/xxxxx
+   CDK_HOSTED_ZONE_ID=Z1234567890ABC
+   CDK_HOSTED_ZONE_NAME=example.com
+   ```
+
+4. **Deploy** the CDK stack
+
+---
+
+## Configuration Validation
+
+Both application and infrastructure configurations are validated at runtime:
+
+- **Application**: Environment variables are available in Vite at build time
+- **Infrastructure**: Configuration is validated using Zod schema when `getConfig()` is called
+
+If validation fails, you'll see detailed error messages indicating which variables are missing or invalid.
+
+### Common Validation Errors
+
+```
+CDK_ENV must be one of: dev, qa, prd
+```
+
+Ensure `CDK_ENV` is set to one of the allowed values.
+
+```
+CDK configuration validation failed: CDK_ASSET_PATH: Invalid type. Expected string
+```
+
+Ensure all required configuration variables are set as the correct type.
+
+---
+
+## Environment-Specific Recommendations
+
+### Development
+
+- Use auto-detected AWS account and region from AWS CLI
+- Deploy to a development AWS account
+- Enable detailed logging in your application
+- Use minimal resource sizes
+- Consider using S3 + CloudFront for cost-effective hosting
+
+### QA
+
+- Use dedicated QA AWS account
+- Configure proper domain names for testing
+- Use production-like configurations
+- Enable monitoring and alerting
+
+### Production
+
+- Use dedicated production AWS account
+- Configure custom domains with SSL/TLS certificates
+- Use appropriate resource sizes
+- Enable comprehensive monitoring, logging, and alerting
+- Implement backup and disaster recovery plans
+- Consider using CloudFront with WAF for protection
+
+---
+
+## Troubleshooting
+
+### CDK Deployment Fails with "Account/Region" Error
+
+**Problem**: CDK deployment fails with an error about missing account or region.
+
+**Solution**:
+
+1. Set `CDK_ACCOUNT` and `CDK_REGION` explicitly in `.env`
+2. Ensure AWS CLI is configured with `aws configure`
+3. Verify with: `aws sts get-caller-identity`
+
+### Application Build Variables Not Available
+
+**Problem**: `import.meta.env.VITE_*` variables are undefined at runtime.
+
+**Solution**:
+
+1. Ensure variables in `.env` are prefixed with `VITE_`
+2. Restart the development server after changing `.env`
+3. Verify with: `echo $VITE_BASE_URL_API`
+
+### CDK Configuration Validation Errors
+
+**Problem**: CDK fails to load configuration with validation errors.
+
+**Solution**:
+
+1. Check `.env` file syntax (no quotes around values unless necessary)
+2. Verify required variables are set
+3. Check for typos in variable names
+4. Ensure enum values match allowed options
+
+### AWS Credentials Issues
+
+**Problem**: CDK cannot access AWS account.
+
+**Solution**:
+
+1. Configure AWS credentials: `aws configure`
+2. Verify access: `aws sts get-caller-identity`
+3. Use AWS SSO if available: `aws sso login --profile YOUR_PROFILE`
+4. Ensure IAM user/role has CDK permissions
+
+---
+
+## Best Practices
+
+1. **Never commit `.env` files** - Use `.gitignore` to exclude them
+2. **Use environment-specific `.env` files** - Keep configurations separate per environment
+3. **Document configuration changes** - Update this guide when adding new variables
+4. **Validate early** - Run CDK synthesis before deployment: `cdk synth`
+5. **Use AWS CDK best practices**:
+   - Always tag resources for cost allocation
+   - Use stack outputs for important values
+   - Implement proper error handling
+   - Test in lower environments first
+6. **Secure sensitive data**:
+   - Use AWS Secrets Manager for secrets
+   - Never commit credentials to version control
+   - Use IAM roles instead of access keys when possible
+7. **Monitor and log**:
+   - Enable CloudWatch logging for CDN and application
+   - Set up CloudWatch alarms for critical metrics
+   - Review logs regularly for issues
+
+<br/>
+
+---
+
+For more information about this project, see the main [README](../README.md) or visit the [documentation](./README.md).
diff --git a/docs/README.md b/docs/README.md
index 3093b25..833628d 100644
--- a/docs/README.md
+++ b/docs/README.md
@@ -5,6 +5,7 @@ Welcome to the project documentation for the React Starter project. This directo
 ## Table of Contents
 
 - [DevOps Guide](./DEVOPS_GUIDE.md): GitHub Actions workflows, CI/CD, and automation.
+- [Configuration Guide](./CONFIGURATION_GUIDE.md): Application and infrastructure configuration, environment variables, and validation.
 - [Infrastructure Guide](./INFRASTRUCTURE_GUIDE.md): AWS CDK Infrastructure as Code.
 
 <br/>