OpenTofu vs Terraform : Key Differences and Comparison

In the infrastructure-as-code (IaC) world, Terraform and OpenTofu are the most popular projects. Understanding how they work, their features, similarities, and differences can help you decide which best suits your needs.

What we will cover:

1. What is OpenTofu?
2. What is Terraform?
3. OpenTofu vs. Terraform — Similarities
4. Differences between OpenTofu and Terraform
5. Table comparison
6. Which should I choose: Terraform or OpenTofu?

OpenTofu is an open-source IaC tool designed to help engineers define, provision, and manage the overall lifecycle of their infrastructure. It is stateful, enabling reliable and predictable changes. Initially, OpenTofu was created as an initiative to keep Terraform open-source, but it became a fork of Terraform from the latest open-source version.

Key features of OpenTofu:

• Modularity – encourages modular design, making it easy to reuse code.
• Declarative configuration – define the end state of the infrastructure and OpenTofu will take care of it.
• State management and encryption – maintains and gives the ability to encrypt the state.
• Community-driven – developed and maintained by a community of contributors that listens to people’s needs and prioritizes new features based on a ranking system that users can directly influence.

Developed by HashiCorp, Terraform was open-source until August 2023. Now, it is a BSL IaC tool that also allows engineers to define, provision, and manage the overall lifecycle of their infrastructure.

Key features of Terraform:

Terraform shares the same key features as OpenTofu. From a key features standpoint, the biggest difference is that Terraform is not community-driven and does not support state encryption.

• Modularity – You can divide your infrastructure into multiple reusable modules.
• Declarative configuration – Users describe the desired state of their infrastructure, and Terraform manages it.
• State management – Terraform tracks resources and their configuration in a state file.
• Widely adopted – Terraform supports over 3k providers.

Because OpenTofu started as a Terraform fork, they share many similarities:

• Declarative language – You define the desired state of the infrastructure and OpenTofu/Terraform takes care of the heavy lifting.
• Provider agnostic – Both work with many providers (AWS, Microsoft Azure, Google Cloud, Kubernetes, Helm, etc.).
• Modularity – Both support creating reusable modules and easy-to-maintain configurations.
• Stateful management – Both use a state file to track your infrastructure.
• Versioning – Configurations can be easily bundled into modules and versioned.
• CI/CD integrations – Both integrate seamlessly with CI/CD tools.
• Ecosystem – They both offer excellent integration ecosystems.

The biggest and most important difference between OpenTofu and Terraform is the licensing. OpenTofu is open-source under the MPL 2.0, and Terraform is under the BSL. Being open-source makes OpenTofu community-driven, and this enables the community to influence the implementation of certain features without being directly influenced by any vendor. However, Terraform is influenced directly by its vendor, HashiCorp, when developing new features.

OpenTofu also offers state encryption, a feature the Terraform community has requested for the last five years but has never received.  This article explains how to encrypt your state using OpenTofu.

In addition to this, with OpenTofu 1.8, you can leverage early variable evaluation, meaning that you can take advantage of variables and locals inside your terraform block and inside your module sources and versions.

As OpenTofu and Terraform continue to evolve, they will probably diverge, meaning that more key differences will emerge in the future.

The table below summarizes the comparison between OpenTofu and Terraform.

Terraform might be the better choice if you are deeply invested in the HashiCorp ecosystem. Otherwise, OpenTofu is a better choice for those who want community-driven development and influence over decisions about the features that get implemented.

Spacelift is an infrastructure orchestration platform that supports both OpenTofu and Terraform, as well as other tools such as Pulumi, CloudFormation, Terragrunt, Ansible, and Kubernetes. Spacelift offers a variety of features that map easily to your OpenTofu and Terraform workflow.

Spacelift stacks enable you to plug in the VCS repository containing your Terraform and OpenTofu configuration files and do a GitOps workflow for them. 

At the stack level, you can add a variety of other components that will influence this GitOps workflow, such as:

• Policies – Control the kind of resources engineers can create, their parameters, the number of approvals you need for runs, where to send notifications, and more.

• Stack dependencies –  Build dependencies between your configurations, and even share outputs between them. There are no constraints on creating dependencies between multiple tools or the number of dependencies you can have.

• Cloud integrations – Dynamic credentials for major cloud providers (AWS, Microsoft Azure, Google Cloud).

• Contexts – Shareable containers for your environment variables, mounted files, and lifecycle hooks.

• Drift detection – Easily detect infrastructure drift and optionally remediate it.

Resources view – Enhanced observability of all resources deployed with your Spacelift account.

OpenTofu and Terraform are currently similar, but as time passes, they will increasingly diverge. The key difference between them remains the fact that OpenTofu is community-driven and people can directly influence what can be implemented, whereas Terraform is subject to HashiCorp’s development objectives. 

Spacelift can greatly enhance workflows for both OpenTofu and Terraform. To learn more about it, create an account today or book a demo with one of our engineers.