Atlantis is an open-source DevOps tool for automating Terraform workflows through pull requests. It enables teams to run terraform plan, review output, and execute apply directly from GitHub, GitLab, Bitbucket, or Azure DevOps PRs instead of running Terraform locally.

At its core, Atlantis listens for version control system webhooks and executes Terraform commands on a server-side environment. When a pull request is opened or updated, it automatically runs a plan and posts the output back as a comment, allowing reviewers to see exactly what infrastructure changes will occur before anything is applied.

The tool is designed to improve collaboration between developers and operations teams by removing the need for shared cloud credentials and manual CLI usage. Developers can propose infrastructure changes through code, while approvals and applies are managed through pull request workflows with optional review gates.

Atlantis is self-hosted and written in Go, typically deployed on Kubernetes, VMs, or container platforms. It does not require a database, instead storing temporary plan state locally during workflows.

It has become a widely adopted “Terraform collaboration layer,” helping organizations standardize infrastructure-as-code workflows while maintaining auditability and control over changes.

Key features include:

• Terraform plan/apply automation via pull requests
• Comments PRs with plan output automatically
• Webhook-driven integration with GitHub, GitLab, Bitbucket, Azure DevOps
• Approval-based apply workflow for safety
• Self-hosted deployment (Docker, Kubernetes, VMs)
• No shared cloud credentials required for developers
• Built-in audit trail through version control history
• Supports multi-repo and team-based Terraform workflows

Common use cases include:

• Managing infrastructure changes via GitOps workflows
• Enabling safe self-service Terraform for developers
• Standardizing Terraform review and approval processes
• Reducing manual infrastructure operations overhead
• Improving auditability of cloud infrastructure changes
• Coordinating multi-team infrastructure management

Atlantis is positioned as a “Terraform pull request automation” system that brings structured, reviewable workflows to infrastructure provisioning, making it easier for teams to collaborate safely on cloud infrastructure at scale.