How To Choose Between Terraform, Pulumi, And OpenTofu

Discover the differences, strengths, and ideal use cases of Terraform, Pulumi, and OpenTofu in the Infrastructure as Code landscape.

Infrastructure as Code (IaC) enables DevOps and cloud teams to manage infrastructure through code instead of manual processes. It ensures consistency, repeatability, and automation in infrastructure provisioning. In the IaC landscape, Terraform, Pulumi, and the open source OpenTofu stand out as the most talked-about tools.

Programming model and language support

Terraform uses a declarative approach through HCL (HashiCorp Configuration Language). It’s purpose-built for defining infrastructure and is relatively easy to learn for infrastructure teams. However, it’s not ideal for complex logic or abstractions.

Pulumi, on the other hand, uses general-purpose programming languages such as Python, JavaScript, TypeScript, Go, and C#, combining both declarative and imperative models. This flexibility empowers developers to reuse existing libraries, implement logic, and write unit tests.

OpenTofu, a fork of Terraform, retains the HCL-based declarative style but focuses on staying fully open source and community-driven.

• Pulumi is ideal for developers; Terraform and OpenTofu suit infrastructure-centric teams.

Ecosystem, providers, and modules

Terraform has the largest ecosystem with an enormous provider registry covering AWS, Azure, GCP, Kubernetes, and more. Thousands of modules are available for reuse on the Terraform Registry.

Pulumi reuses Terraform’s provider plugins under the hood, giving it broad compatibility. It also provides its own registry with examples and native SDKs.

OpenTofu maintains provider compatibility with Terraform and supports all Terraform providers.

• Terraform leads in maturity and breadth. Pulumi is catching up with developer-first extensions.

State management and backend support

State files track the current state of infrastructure. Terraform and OpenTofu use .tfstate files, which can be stored locally or remotely (e.g., S3, Terraform Cloud).

Pulumi manages state as ‘stacks’, stored either in Pulumi Service, local files, or remote backends (AWS S3, Azure Blob, etc). It includes built-in encryption and access control when using the Pulumi cloud.

All tools support state locking, drift detection, and remote state sharing across teams.

• Pulumi offers a developer-friendly model; Terraform and OpenTofu offer more traditional ops-style state management.

Community, governance, and licensing

HashiCorp, the creator of Terraform, changed its licence to Business Source License (BSL) in 2023, limiting commercial use in SaaS environments. This move led to the creation of OpenTofu, which is governed by the Linux Foundation and licensed under the open source MPL 2.0.

Pulumi remains open core, offering a cloud service for premium features but keeping the SDK open source.

OpenTofu is driven entirely by community contributions and is fully open source, making it ideal for those concerned about vendor lock-in.

• For open governance, OpenTofu is best. For established enterprise features, Terraform still dominates.

Testing, CI/CD integration, and automation

Pulumi’s use of programming languages allows seamless integration with standard testing frameworks like unittest or pytest. You can write tests to validate infrastructure logic before deployment.

Terraform supports testing through tools like Terratest, which use Go to test modules. It’s powerful but adds extra complexity.

OpenTofu supports the same ecosystem as Terraform and integrates well with CI/CD tools like Jenkins, GitHub Actions, and GitLab CI.

• Pulumi excels in automated testing; Terraform and OpenTofu are battle-tested in CI/CD.

Secrets, policies, and security

All three tools support secure secret storage via tools like Vault, AWS KMS, or environment variables.

Pulumi provides native secrets management in its service, encrypting secrets automatically.

Terraform Enterprise supports Sentinel, a policy-as-code framework (proprietary), while OpenTofu encourages using Open Policy Agent (OPA) as a community-friendly alternative.

• Pulumi simplifies secrets. OpenTofu promotes openness with tools like OPA.

Performance and scalability

All tools support parallel execution and scalable plans. Pulumi may experience a slight overhead due to the runtime of general-purpose languages, especially during cold starts.

Terraform and OpenTofu are leaner for large-scale infrastructure with hundreds of modules, due to their simpler execution model.

• Terraform and OpenTofu are leaner at scale; Pulumi trades some speed for flexibility.

Use case suitability

Pros and cons at a glance

Terraform

√ Mature, stable, large ecosystem

√ Many providers and integrations

× BSL licensing limits use

× Less flexible for complex logic

Pulumi

√ Uses real programming language

√ Easy testing and logic abstraction

√ Friendly for developers

× Smaller community

× Slightly steeper learning curve for non-devs

OpenTofu

√ Fully open source and transparent

√ No licensing restrictions

√ Terraform-compatible

× Younger project, evolving ecosystem

× Fewer commercial tools (for now)

How Terraform, Pulumi and OpenTofu compare with each other

Final recommendation

The right IaC tool depends on your team’s structure, values, and technical needs:

• Choose Terraform if you want a stable and mature tool backed by years of adoption (and you’re okay with BSL restrictions).
• Choose Pulumi if you’re a developer-first team looking to build infrastructure with the power of familiar languages.
• Choose OpenTofu if you want the freedom of open source with Terraform compatibility and community-driven innovation.