What makes C3X different?

C3X ships with an independent open-source pricing API, fully offline mode, free budget guardrails, and built-in cost optimization recommendations. Everything is free and open source. No features locked behind a paid tier. We believe cost estimation is infrastructure, not a SaaS product.

Does it work without an API key?

Yes. You can self-host the pricing API or use fully offline mode with a local SQLite database. Run c3x pricing sync to download pricing data, then c3x estimate --offline for zero network calls.

How accurate are the estimates?

C3X uses the same pricing data published by AWS, Azure, and GCP through their official bulk pricing APIs. It supports over 1,100 Terraform resources including usage-based resources like Lambda, S3, and data transfer.

Which IaC tools are supported?

Terraform, Terragrunt, and AWS CloudFormation are fully supported. Pulumi and Azure Bicep support is on our roadmap.

Can I use it in CI/CD?

Yes. C3X integrates with GitHub Actions, GitLab CI, Bitbucket Pipelines, Azure Pipelines, Atlantis, and Spacelift. Use the c3x comment command to post cost estimates directly in pull requests.

Yes. C3X is Apache 2.0 open source. The CLI, pricing API, and all features including recommendations, budget guardrails, what-if scenarios, and offline mode are completely free. No paid tiers required. No rug pulls.

🔓Apache 2.0. Free forever, no feature gates

Cost Estimates for YourCloud Infrastructure

before you deploy

Open source CLI for Terraform, Terragrunt, and CloudFormation with optimization recommendations, budget guardrails, and fully offline mode. No API key required.

Get Started

View on GitHub

Works with your infrastructure stack

TerraformTerragruntCloudFormationAWSAzureGoogle Cloud

1,100+

Terraform resources supported

Cloud providers

Free and open source

Network calls in offline mode

See It In Action

Real Output, Not Mockups

What you actually see when you run C3X on a Terraform project.

terminal

Detected Terraform project at ./infrastructure

Name                                         Monthly Qty  Unit         Monthly Cost

aws_instance.web_server
├─ Instance usage (Linux/UNIX, on-demand, m5.xlarge)  730  hours             $140.16
├─ root_block_device
│  └─ Storage (general purpose SSD, gp2)               50  GB                  $5.00
└─ ebs_block_device[0]
   ├─ Storage (provisioned IOPS SSD, io1)            1,000  GB                $125.00
   └─ Provisioned IOPS                                800  IOPS               $52.00

aws_db_instance.main
├─ Database instance (on-demand, db.r5.large)          730  hours             $175.20
└─ Storage (general purpose SSD, gp2)                  100  GB                 $11.50

aws_nat_gateway.main
├─ NAT gateway                                         730  hours              $32.85
└─ Data processed                               10,000.00  GB                $45.00

PROJECT TOTAL                                                                $586.71

──────────────────────────────────────────────────────
1 project | 3 resources | $586.71/mo

How It Works

From Zero to Cost Visibility

Three steps. No account required. Works with any Terraform project.

Install

One command. Works on macOS, Linux, Windows, and Docker. No account required.

$brew install c3xdev/tap/c3x

Estimate

Point at your Terraform project. Get a full cost breakdown in seconds.

$c3x estimate --path .

Optimize

Get actionable suggestions: newer instance types, better storage, architecture improvements.

$c3x recommend --path .

Read the full quickstart guide

Features

Everything You Need to Manage Cloud Costs

From cost estimation to optimization recommendations, budget enforcement, and offline mode.

1,100+ Resources

AWS, Azure, and Google Cloud. Terraform, Terragrunt, and CloudFormation. Usage-based resources like Lambda and S3 supported via usage files.

Learn more

Cost Recommendations

Suggests newer instance generations, gp2 to gp3 migrations, VPC endpoints for NAT Gateway, and more. Runs locally, no cloud subscription.

Learn more

Budget Guardrails

Add --budget 1000 to your CI pipeline. Exits with code 1 if the estimate exceeds your limit. Free, no paid subscription required.

Learn more

What-If Scenarios

Test cost impact of changes without modifying Terraform code. --what-if lets you override any resource attribute on the fly.

Learn more

Fully Offline

Download pricing data once with c3x pricing sync. Then estimate without any network calls. Perfect for air-gapped environments.

Learn more

Self-Hosted Pricing

Independent pricing API that scrapes directly from AWS, Azure, and GCP. No vendor lock-in. Your data stays on your infrastructure.

Learn more

Comparison

How C3X Compares

An honest look at how C3X stacks up against other Terraform cost estimation tools.

Feature	C3X	Infracost	OpenInfra Quote	HCP Terraform
Open source CLI
No API key required
Fully offline mode
Self-hosted pricing API	Free	Paid	Built-in
Budget guardrails (CLI)	--budget flag	OPA/Rego	OPA
Cost recommendations	Free	Paid
What-if scenarios	--what-if flag
AWS resources	700+	700+	~50	~14
Azure resources	300+	300+		~24
GCP resources	100+	100+		~3
Terragrunt support
CloudFormation		Paid
PR comments	Free	Free		Built-in

Based on publicly available documentation as of April 2026. Suggest a correction

The Difference

Before & After C3X

See how teams transform their cloud cost management from reactive firefighting to proactive optimization.

Without C3X

Surprise cloud bills after deployment
Manual spreadsheet estimation
No cost gate in CI/CD pipelines
Vendor lock-in to proprietary pricing APIs

With C3X

Know exact costs before you merge
Automatic optimization suggestions
Budget guardrails in every pipeline
Fully offline, own your data

ROI Calculator

See Your Potential Savings

Drag the slider to estimate how much cost visibility and optimization recommendations could save.

Monthly Cloud Spend$500K

$10K$5M

Annual Savings

$688K

projected

Time to ROI

6.5 wks

average

vs. No Visibility

more efficient

Integrations

Fits Into Your Workflow

Works with the IaC tools and CI/CD platforms you already use.

TerraformIaC

TerragruntIaC

CloudFormationIaC

GitHub ActionsCI/CD

GitLab CICI/CD

Bitbucket PipelinesCI/CD

Azure PipelinesCI/CD

AtlantisPlatform

SpaceliftPlatform

Roadmap

Where We're Going

C3X is building toward full infrastructure simulation. Here's the journey.

Now

v1.0 Open Source CLI

Cost estimation for 1,100+ Terraform resources
Optimization recommendations
Budget guardrails for CI/CD
What-if cost scenarios
Fully offline mode
Self-hosted pricing API

Coming Soon

v2.0 C3X Cloud

Multi-project cost dashboard
Historical cost tracking over time
Team cost allocation views
Compare estimates to real cloud bills
Scheduled cost reports

Future

v3.0 Cloud Digital Twin

Simulate infrastructure changes before deploying
Predict cost + performance impact together
Replay millions of what-if scenarios
Confidence-backed deployment recommendations

FAQ

Frequently Asked Questions

Everything you need to know about C3X.

Start Estimating in
30 Seconds

One command to install. Point at your Terraform project. See costs instantly.

$brew install c3xdev/tap/c3x

Also available via Docker:

docker pull c3xdev/c3x

Read the Docs Star on GitHub

Cost Estimates for YourCloud Infrastructure

Real Output, Not Mockups

From Zero to Cost Visibility

Install

Estimate

Optimize

Everything You Need to Manage Cloud Costs

1,100+ Resources

Cost Recommendations

Budget Guardrails

What-If Scenarios

Fully Offline

Self-Hosted Pricing

How C3X Compares

Before & After C3X

Without C3X

With C3X

See Your Potential Savings

Fits Into Your Workflow

Where We're Going

v1.0 Open Source CLI

v2.0 C3X Cloud

v3.0 Cloud Digital Twin

Frequently Asked Questions

Start Estimating in 30 Seconds

Start Estimating in
30 Seconds