The Linux Foundation fork of Terraform, created in 2023 after HashiCorp relicensed Terraform under the BSL. OpenTofu is a drop-in replacement at the CLI level — your existing .tf files, providers, and state work without modification — but governance has shifted to a foundation, and the community has shipped features Terraform has not, notably state encryption at rest, early variables in backend configuration, and provider iteration improvements.
High fit for teams that need a permissive open-source license for compliance or competitive reasons (SaaS vendors offering Terraform-compatible runners, internal platforms that ship IaC to customers), and for engineering organizations philosophically opposed to vendor lock-in. Most users notice no day-to-day difference; the drop-in promise has held through several major releases.
Watch out for: provider compatibility is excellent but not perfect — a small number of HashiCorp-maintained providers occasionally lag on OpenTofu releases. The ecosystem of CI integrations, IDE plugins, and stack frameworks (Terragrunt, Atmos, Atlantis) supports OpenTofu but the experience is sometimes a few weeks behind Terraform's, and community velocity, while real, is smaller than HashiCorp's headcount on Terraform itself.
