Top 5 Open Source Terraform Tools for 2025

HashiCorp Terraform lets you define both cloud and on-prem resources in human-readable configuration files that you can version, reuse, and share. You can then use a consistent workflow to provision and manage all of your infrastructure throughout its lifecycle.

However, when it comes to managing Terraform code, there are many tools that can help. In this post, we will review the top 5 open source Terraform tools for 2025.

Criteria#

1. Open Source: The tool must be open source.
2. Terraform: The tool must support Terraform. However, HashiCorp transitioned Terraform's license from MPL v2 to BSL, affecting versions beyond v1.5.7. These tools support Terraform v1.5.7 or earlier, and advocate to use OpenTofu instead.

Digger#

Digger is an open-source CI/CD orchestrator for Terraform. It spins up jobs in your existing CI (GitHub Actions, GitLab CI, etc.) instead of running its own CI-like infrastructure.

License: Open Source (Apache 2.0) - Digger is developed by DGGR LIMITED and is available under the Apache 2.0 license. While Digger itself is open source, the company offers an Enterprise Edition with additional features such as drift detection, role-based access control (RBAC) via Open Policy Agent (OPA), and audit log retention.

Features

• CI Integration: Runs Terraform within existing CI pipelines (GitHub Actions, GitLab CI, etc.)
• Multi-Cloud Support: Works with AWS, GCP, Azure, and integrates with various CI platforms
• PR Automation: Executes terraform commands based on pull requests with results posted as comments
• Locking & Concurrency: Prevents race conditions with PR-level locks
• Policy & Compliance: Enforces rules with Open Policy Agent and detects infrastructure drift
• Plan Management: Stores and persists plan outputs for review before application

Checkov#

Checkov is a static code analysis tool for scanning infrastructure as code (IaC) files for misconfigurations that may lead to security or compliance problems.

Checkov includes more than 750 predefined policies to check for common misconfiguration issues. Checkov also supports the creation and contribution of custom policies. It scans cloud infrastructure provisioned using Terraform/OpenTofu, Terraform plan as well as other IaC solutions such as Cloudformation, Helm charts, Kustomize, Dockerfile, and etc. It detects security and compliance misconfigurations using graph-based scanning.

License: Open Source (Apache 2.0) - Checkov is developed by Bridgecrew, which was acquired by Palo Alto Networks. While Checkov itself is open source, it powers the commercial Prisma Cloud Application Security platform.

Features

• Over 1000 built-in policies for AWS, Azure and Google Cloud security and compliance
• Multi-platform scanning: Terraform/OpenTofu, CloudFormation, Kubernetes, Dockerfile, and more
• CI/CD integration: Scans Argo Workflows, Azure Pipelines, GitHub Actions, GitLab CI and other pipeline files
• Context-aware policies with graph-based scanning
• Supports multiple policy formats (Python and YAML)
• Detects credentials and secrets using pattern matching and entropy detection
• Evaluates provider settings and variables
• Supports suppression of false positives
• Multiple output formats: CLI, JSON, CSV, SARIF, and more

Example

checkov -f tf.json
Check: CKV_AWS_21: "Ensure all data stored in the S3 bucket have versioning enabled"
	FAILED for resource: aws_s3_bucket.customer
	File: /tf/tf1.json:224-268
	Guide: https://docs.prismacloud.io/en/enterprise-edition/policy-reference/aws-policies/s3-policies/s3-16-enable-versioning

		225 |               "values": {
		226 |                 "acceleration_status": "",
		227 |                 "acl": "private",
		228 |                 "arn": "arn:aws:s3:::mybucket",

Infracost#

infracost.io is an open-source cost estimation tool for Terraform.

It enables a shift-left approach for cloud costs by providing cost estimates for Terraform before deployment. Additionally, it can check for FinOps best practices in accordance with the Well-Architected Frameworks of cloud vendors. Infracost works with AWS, Azure and Google Cloud.

License: Open Source (MIT) - Infracost is developed by Infracost Inc. and is available under the Apache 2.0 license. While the core Infracost CLI is open source, the company offers additional services through Infracost Cloud, which provides features like centralized management, budget enforcement, and policy automation.

Features

• Cost Estimation: Estimates the cost of your Terraform code before you run it
• Cloud Providers: Supports AWS, Azure, GCP, and Kubernetes
• CI/CD Integration: Works with GitHub Actions, GitLab CI, and more
• Custom Formats: Supports Terraform plan files and Terraform HCL
• Detailed Reports: Provides detailed reports with cost breakdowns

Terramate#

Terramate is an open-source Infrastructure as Code (IaC) orchestration and management platform that turns your IaC into a lightning-fast platform.

It enables teams to build, deploy, manage and observe cloud infrastructure with Infrastructure as Code (IaC) tools such as Terraform, OpenTofu, Terragrunt, Kubernetes and others.

License: Open Source (MPL 2.0) - Terramate is developed by Terramate GmbH and is available under the Mozilla Public License 2.0. While the core Terramate CLI is open source, the company offers Terramate Cloud, a commercial platform that provides additional features such as observability, drift detection, asset inventory management, and policy enforcement.

Features

• Stacks: Groups related infrastructure resources for better management and reduced risk.
• Code Generation: Automates config creation to ensure consistency and minimize duplication.
• Orchestration: Graph-based execution optimizes deployments by targeting only changed stacks.
• CI/CD Integration: Works with GitHub Actions, GitLab CI/CD, and more for automated workflows.
• Observability & Drift Detection: Monitors infrastructure changes and ensures alignment.
• Asset Management: Centralized inventory of resources across teams and environments.
• Developer Self-Service: Enables easy provisioning of production-grade infrastructure.

Terragrunt#

Terragrunt is a flexible orchestration tool that allows Infrastructure as Code to scale. It is a thin wrapper around Terraform that provides extra tools for working with multiple Terraform modules.

License: Open Source (MIT) - Terragrunt is developed by Gruntwork and is available under the MIT License. While Terragrunt itself is open source, Gruntwork offers commercial support and additional services through their platform, which provides a comprehensive suite of infrastructure as code (IaC) tools and modules.

Features

• DRY Code Management: Reuse Terraform/OpenTofu code across environments, reducing duplication.
• Simplified Backend Configs: Centralizes state management settings for easier maintenance.
• Multi-Module Execution: Runs commands across multiple modules for streamlined deployments.
• Hooks & Automation: Supports pre/post execution hooks for extended automation.
• Dependency Graph Execution: Ensures proper execution order for interdependent modules.
• Structured Logging & Telemetry: Supports JSON logs and OpenTelemetry for better observability.