stackprice

AWS CDK infrastructure pricing estimation CLI — know what it costs before you deploy.

stackprice is an open source CLI tool that reads your synthesized CDK output and returns an itemized monthly cost estimate — per resource, per stack, and in total — before a single dollar is spent.

This implementation is written by vibe-coding.

cdk synth
stackprice breakdown --dir ./cdk.out

Stack: ApiStack   Region: us-east-1
┌───────────────┬──────────────────────┬──────────────┐
│ Resource ID   │ Type                 │ Monthly Cost │
├───────────────┼──────────────────────┼──────────────┤
│ WebServer     │ AWS::EC2::Instance   │ $140.16      │
│ Database      │ AWS::RDS::DBInstance │ $12.41       │
│ NATGateway    │ AWS::EC2::NatGateway │ $32.85       │
├───────────────┴──────────────────────┼──────────────┤
│ Stack Subtotal                       │ $185.42      │
└──────────────────────────────────────┴──────────────┘
┌────────────┬───────────────────────┬─────────────────┬──────────────────────────────────────┐
│ Resource ID│ Type                  │ Unit Price      │ Note                                 │
├────────────┼───────────────────────┼─────────────────┼──────────────────────────────────────┤
│ NATGateway │ AWS::EC2::NatGateway  │ $0.04/unit      │ Usage-based — provide via --usage-file│
│ ApiHandler │ AWS::Lambda::Function │ $0.0000167/unit │ Usage-based — provide via --usage-file│
└────────────┴───────────────────────┴─────────────────┴──────────────────────────────────────┘

TOTAL ESTIMATED MONTHLY COST: $185.42 + usage-based

Why stackprice

AWS CDK engineers have no open source way to estimate infrastructure costs before deployment. You write CDK code, deploy, and discover the financial impact only when the bill arrives.

stackprice fixes that. It plugs directly into your existing CDK workflow — no registration, no external services, no changes to how you write CDK. Just run cdk synth as you normally would, then point stackprice at the output.

Installation

# Via npm (requires Node.js >= 20)
npm install -g stackprice

# Via npx (no install required)
npx stackprice breakdown --dir ./cdk.out

Quick Start

# Synthesize your CDK app first
cdk synth

# Estimate all stacks
stackprice breakdown --dir ./cdk.out

# Estimate a specific stack only
stackprice breakdown --dir ./cdk.out --stack MyApiStack

# Output as JSON for CI/CD pipelines
stackprice breakdown --dir ./cdk.out --output json --out-file estimate.json

# One-line summary
stackprice breakdown --dir ./cdk.out --output summary

# Compare two cost estimates
stackprice diff before.json after.json
stackprice diff before.json after.json --format summary

# Provide usage estimates for Lambda, S3, NAT Gateway, etc.
stackprice breakdown --dir ./cdk.out --usage-file ./stackprice-usage.yml

# Generate a usage estimates file (no AWS credentials needed)
stackprice generate usage-file --dir ./cdk.out

Credentials

stackprice uses the AWS Price List API to fetch pricing data. This API is free to call and requires only one read-only permission.

Minimum IAM permission required:

{
  "Effect": "Allow",
  "Action": ["pricing:GetProducts"],
  "Resource": "*"
}

stackprice uses the standard AWS credential chain. If you can run cdk deploy, your credentials already work. No extra setup needed.

aws configure

Or: aws login (IAM Identity Center / SSO)

Region resolution order:

1. Region declared in the CDK template
2. --region flag
3. AWS_DEFAULT_REGION environment variable
4. AWS_REGION environment variable
5. Active AWS CLI profile region (~/.aws/config)
6. Falls back to us-east-1 with a visible warning

CLI Reference

stackprice breakdown

Analyze a CDK cloud assembly and output pricing estimates.

| Flag | Type | Default | Description | | --- | --- | --- | --- | | --dir | string | cdk.out | Path to CDK cloud assembly directory | | --stack | string | all | Name of specific stack to analyze | | --region | string | from template | AWS region for pricing lookup | | --output | enum | table | Output format: table, json, summary | | --out-file | string | — | Write output to file instead of stdout | | --usage-file | string | — | Path to YAML or JSON file with usage estimates | | --no-cache | bool | false | Skip cache, always fetch fresh pricing | | --no-color | bool | false | Disable color output | | --verbose | bool | false | Show pricing API queries and resolution details |

stackprice diff

Compare two breakdown JSON outputs and show cost delta per resource and in total.

| Flag | Type | Default | Description | | --- | --- | --- | --- | | --format | enum | table | Output format: table, json, summary | | --out-file | string | — | Write output to file instead of stdout | | --no-color | bool | false | Disable color output |

stackprice generate usage-file

Generate a pre-populated usage estimates file from your CDK cloud assembly. Does not require AWS credentials.

| Flag | Type | Default | Description | | --- | --- | --- | --- | | --dir | string | cdk.out | Path to CDK cloud assembly directory | | --stack | string | all | Filter to a specific stack | | --format | enum | yaml | Output format: yaml or json | | --out-file | string | auto | Output file path | | --force | bool | false | Overwrite existing file | | --types | string | all | Comma-separated types: Lambda,S3,SQS,SNS,ApiGateway,NatGateway,CloudFront |

Usage File

Usage-based resources (Lambda, S3, SQS, SNS, API Gateway, NAT Gateway, CloudFront) show unit prices only by default. Provide a usage file to get estimated monthly costs.

Generate a starter file (easiest approach):

stackprice generate usage-file --dir ./cdk.out
# Creates stackprice-usage.yml with all usage-based resources pre-populated

Or write it manually (YAML):

# stackprice-usage.yml
ApiHandler5E7490E8:
  requests_per_month: 5000000   # Lambda invocations per month
  avg_duration_ms: 200          # average duration in milliseconds
  memory_mb: 256                # memory in MB (optional, defaults to 128)

DataBucketE3889A50:
  storage_gb: 500               # GB stored per month

VPCPublicSubnet1NATGateway:
  data_transfer_gb: 1000        # GB processed per month
  # Fixed hourly cost ($32.85/month) included automatically

MyApi49610EDF:
  requests_per_month: 2000000   # API Gateway REST API calls per month

MyDistribution:
  monthly_requests: 10000000    # CloudFront requests per month
  monthly_transfer_gb: 100      # GB transferred to users (US zone pricing)

JSON format is also supported:

{
  "ApiHandler5E7490E8": {
    "requests_per_month": 5000000,
    "avg_duration_ms": 200,
    "memory_mb": 256
  },
  "DataBucketE3889A50": {
    "storage_gb": 500
  }
}

Usage file keys can use either the full logical ID (ApiHandler5E7490E8) or the display name without the CDK hash suffix (ApiHandler) — both work.

Run with:

stackprice breakdown --dir ./cdk.out --usage-file ./stackprice-usage.yml

Estimates use Tier 1 pricing. Actual costs may be lower at high volume due to AWS tiered pricing discounts.

CI Integration

Add cost estimates or cost diffs as comments on every pull request using GitHub Actions — no extra services or accounts required.

# .github/workflows/cost.yml
- name: Estimate cost
  run: stackprice breakdown --dir ./cdk.out --output json --out-file estimate.json

See CI Integration for complete workflow recipes including cost diff on PRs.

Supported AWS Resources

| Resource Type | Pricing Model | | --- | --- | | AWS::EC2::Instance | Fixed (on-demand hourly × 730 hrs/month) | | AWS::RDS::DBInstance | Fixed (instance hourly × 730 hrs/month + storage per GB-month †) | | AWS::ECS::TaskDefinition | Fixed (Fargate vCPU + memory × 730 hrs/month) | | AWS::DynamoDB::Table | Fixed (provisioned) or Usage-based (on-demand) | | AWS::ElastiCache::CacheCluster | Fixed (on-demand hourly × 730 hrs/month) | | AWS::EKS::Cluster | Fixed (control plane $0.10/hr × 730 hrs/month) | | AWS::SecretsManager::Secret | Fixed ($0.40/secret/month) | | AWS::EC2::NatGateway | Mixed — Fixed ($0.045/hr) + Usage-based ($0.045/GB processed) | | AWS::Lambda::Function | Usage-based (invocations × duration × memory) | | AWS::S3::Bucket | Usage-based (storage per GB) | | AWS::SQS::Queue | Usage-based (requests) | | AWS::SNS::Topic | Usage-based (notifications) | | AWS::ApiGateway::RestApi | Usage-based (REST API calls, Tier 1 rate) | | AWS::CloudFront::Distribution | Usage-based (requests + data transfer, US zone) | | AWS::Kinesis::Stream | Fixed (provisioned: $0.015/shard-hour × shards × 730; on-demand: $0.04/stream-hour × 730) | | AWS::Logs::LogGroup | Usage-based (ingestion $0.50/GB + storage $0.03/GB-month †) | | AWS::KinesisFirehose::DeliveryStream | Usage-based (Direct PUT ingestion $0.08/GB) | | AWS::StepFunctions::StateMachine | Usage-based (Standard: $0.000025/transition; Express: per-request + duration) |

† RDS storage cost uses hardcoded rates verified 2026-04-24. See AWS RDS Pricing for current rates.

† CloudWatch Logs storage rate ($0.03/GB-month) uses a hardcoded rate verified 2026-04-24. See AWS CloudWatch Pricing for current rates.

Unsupported resource types are skipped with a warning and listed at the end of output. They never cause the tool to fail.

CloudFormation Conditions

If your CDK app uses CloudFormation Conditions to toggle resources on or off, stackprice handles them safely:

• Conditioned resources are excluded from the cost total
• They are shown in a separate section with their condition name
• Condition evaluation is planned for a future release

How It Works

1. Reads cdk.out/manifest.json to discover all stacks in your app
2. Parses each CloudFormation template JSON file
3. Resolves the AWS region using the standard credential chain
4. Queries the AWS Price List API in parallel for each resource type
5. Caches responses locally for 24 hours to avoid redundant API calls
6. Outputs a cost breakdown sorted by monthly cost (highest first)

stackprice never reads your deployed resources, never modifies your infrastructure, and never sends your template data to any external service. All processing is local.

Roadmap

Shipped: see CHANGELOG for the full history of v0.1.0 through v0.7.0.

Planned:

| Version | Feature | | --- | --- | | v0.8.0 | GitHub Action — suneelsristi/stackprice-action for PR comments | | v0.8.0 | RDS IOPS pricing (io1/io2) | | v0.8.0 | AWS::EC2::EIP — pending Pricing API availability | | v1.0.0 | Native CloudFormation template support (outside CDK) | | v1.0.0 | VS Code extension with inline cost annotations |

Contributing

Contributions are welcome. For significant changes, open an issue first to discuss the approach.

Branch workflow:

• main — stable, protected
• feature/xxx — new features
• bugfix/xxx — bug fixes
• chore/xxx — tooling and config

License

MIT — free for personal and commercial use.

Built with AWS SDK for JavaScript v3, commander.js, cli-table3, and chalk. Implementation written with Claude Code.