Why Terraform Feels Slow: Understanding Parallelism

Terraform can perform resource operations concurrently, which can dramatically reduce apply time — but parallelism is a tradeoff. Too low and runs drag; too high and you can hit provider API rate limits, timeouts, or flaky behavior that’s hard to debug.

In the full guide, we cover:

• What Terraform “parallelism” actually controls (and what it doesn’t)
• How the default behavior works during plan/apply
• When tuning -parallelism helps (and when it just increases failure rate)
• Practical strategies for reliability: rate-limit awareness, batching, and dependency shaping
• Tips for scaling large IaC codebases without turning applies into roulette

➡️ Read the full article on our blog:

https://spacelift.io/blog/terraform-parallelism