Hidde de Smet offers an expert comparison of Azure Bicep, Terraform, and OpenTofu for Infrastructure as Code. This comprehensive post supports infrastructure and DevOps professionals in selecting tools for Azure, multi-cloud, and open-source strategies.

Bicep vs Terraform vs OpenTofu: Your Infrastructure as Code Options in 2025

Written by Hidde de Smet

Overview

This comprehensive article analyzes and compares three key Infrastructure as Code (IaC) tools: Azure Bicep, HashiCorp Terraform, and OpenTofu (an open-source Terraform fork governed by the Linux Foundation). The post offers practical guidance based on hands-on experience, thoughtful feature analysis, best practices, and the impact of industry changes, like IBM’s acquisition of HashiCorp and resulting ecosystem shifts.

Table of Contents

  1. Quick comparison overview
  2. Core differences
  3. Syntax and developer experience
  4. Cloud coverage: scope and depth
  5. State management
  6. Performance and reliability
  7. Best practices
  8. Learning curve
  9. Cost factors
  10. Team and organizational impact
  11. Advanced use cases
  12. Recommendation framework
  13. Future developments
  14. IBM acquisition impact
  15. OpenTofu as an alternative
  16. Other IaC tools
  17. Key takeaways

1. Quick Comparison Overview

Aspect Bicep Terraform OpenTofu
Cloud Support Azure only Multi-cloud Multi-cloud (same as Terraform)
Learning Curve Gentle for Azure Moderate Identical to Terraform
State Management Azure-managed Manual/Remote Manual/Remote (same as Terraform)
Syntax Clean, intuitive Verbose Identical to Terraform
Features Azure-focused Full/Cloud Same feature set as Terraform
Community Growing Large Emerging (Terraform-compatible)
Vendor Microsoft IBM Linux Foundation
License MIT MPL 2.0 MPL 2.0
Best For Azure-first teams Multi-cloud Open-source Terraform advocates

2. Core Philosophical Differences

Bicep: Azure-native and tightly integrated with Azure Resource Manager (ARM), intended specifically for Azure cloud management.

Terraform: Multicloud-agnostic, serving as a universal language for many cloud and on-premises providers through its provider ecosystem.

OpenTofu: Open-source fork of Terraform, governed by the Linux Foundation, with a focus on community-driven development and vendor-independence. Nearly 100% compatible with Terraform syntax and features.

3. Syntax and Developer Experience

Bicep: Clarity through Simplicity

Bicep, designed as a friendlier ARM template alternative, feels natural for Azure developers and provides strong coding support (IntelliSense, type checking, symbolic references).

param location string = resourceGroup().location
param storageAccountName string = 'mystorageacct${uniqueString(resourceGroup().id)}'

resource storageAccount 'Microsoft.Storage/storageAccounts@2024-01-01' = {
  name: storageAccountName
  location: location
  sku: { name: 'Standard_LRS' }
  kind: 'StorageV2'
  properties: { accessTier: 'Hot' }
}

output storageAccountKey string = storageAccount.listKeys().keys[0].value

Terraform: Consistency Across Clouds

Terraform’s HCL provides a consistent, if verbose, framework usable for Azure, AWS, GCP, and many more.

variable "location" {
  description = "Azure region for resources"
  default     = "West Europe"
}
resource "azurerm_storage_account" "example" {
  name                     = "mystorageacct${random_string.suffix.result}"
  resource_group_name      = var.resource_group_name
  location                 = var.location
  account_tier             = "Standard"
  account_replication_type = "LRS"
  account_kind             = "StorageV2"
  access_tier              = "Hot"
}
resource "random_string" "suffix" { length = 8 }
output "storage_account_key" { value = azurerm_storage_account.example.primary_access_key }

4. Cloud Coverage: Scope vs. Depth

Bicep: Azure Excellence

  • Supports all Azure services—immediate with public preview
  • Latest Azure API versions available instantly
  • Azure features such as managed identities, native Key Vault integration
  • Direct ARM compatibility

Terraform: Multi-Cloud Mastery

  • 3,000+ providers for cloud and third-party services
  • Consistent workflow for AWS, GCP, Azure, Kubernetes, and more
  • Hybrid and on-premises resource support

5. State Management

Bicep

  • Uses Azure Resource Manager for state (no local files)
  • Simplifies team collaboration, removes state file conflicts

Terraform/OpenTofu

  • Explicit state files (local or remote)
  • Supports import, fine-grained state control, but requires careful management and locking
Bicep Advantages Bicep Limitations
No state conflicts Tied to Azure paradigm
Team collaboration Less flexible for complex
Auto orphan cleanup Azure only
What-if operations No cross-tenant resource

6. Performance and Reliability

  • Bicep: Faster Azure deployments via direct ARM, optimized orchestration, and better Azure error messages.
  • Terraform: Improved performance lately, plan outputs are more detailed, but some provider-specific errors are cryptic.

7. Best Practices

When Bicep Excels

  • Azure-centric organizations
  • Immediate use of new Azure services/versions
  • Integrated Microsoft development experiences
  • Reduced complexity for ARM transitions

Example: Bicep modules structure

param environmentName string
module networking 'modules/networking.bicep' = {
  name: 'networking-deployment'
  params: { environmentName: environmentName }
}

When Terraform Excels

  • Multi-cloud, hybrid cloud, or edge environments
  • Teams leveraging a broad provider and module ecosystem
  • Advanced state, migration, or resource import use cases

Example: Terraform modules and backend

terraform {
  required_providers { azurerm = { source = "hashicorp/azurerm" version = "~> 4.34.0" } }
  backend "azurerm" {
    resource_group_name  = "terraform-state-rg"
    storage_account_name = "terraformstatestorage"
    container_name       = "tfstate"
    key                  = "prod.terraform.tfstate"
  }
}

8. Learning Curve Considerations

  • Bicep: Quick for Azure developers (1–2 weeks for basic skills)
  • Terraform: Steeper, especially for cross-cloud concepts (2–4 weeks for basics)

9. Cost Considerations Beyond Licensing

  • Bicep minimizes operational and training costs for Azure-focused teams
  • Terraform requires more initial investment but pays off in multi-cloud flexibility
  • Consider vendor lock-in: Bicep ties you to Azure; Terraform/OpenTofu are provider-agnostic

10. Team and Organizational Factors

  • Bicep: Best for Microsoft-standardized organizations and teams
  • Terraform/OpenTofu: Favored for diversity, large/complex teams, and career flexibility

11. Advanced Use Cases

  • Large enterprise deployments benefit from either tool, based on scope
  • CI/CD and GitOps: Both have strong DevOps integrations (GitHub Actions, Azure DevOps)
  • Real hybrid approaches: Terraform for foundational/shared infra, Bicep for application-layer Azure resources

12. Recommendation Framework

Choose Bicep if

  • Azure-focused (80%+)
  • Simplicity and low maintenance desired
  • Migrating from ARM
  • Need immediate Azure feature access

Choose Terraform if

  • Multi-cloud/hybrid infrastructure
  • Broad community or provider ecosystem needed
  • Complex state management required

Choose OpenTofu if

  • Open-source governance is a priority
  • Avoiding corporate/vendor dependency
  • Need drop-in Terraform compatibility

Hybrid Approach: Use Terraform for foundational layers; Bicep for application resources in Azure.

13. Future Developments

Bicep

  • More robust module ecosystem
  • Cross-subscription deployment improvements
  • Enhanced validation and testing

Terraform

  • Faster performance
  • Improved provider integrations

14. IBM Acquisition Impact

The 2024 IBM acquisition of HashiCorp introduces uncertainty about Terraform’s open source future and possible licensing change risks.

  • Opportunities: Greater enterprise integration, increased resources, improved hybrid focus.
  • Risks: Potential future licensing restrictions, community drift, vendor lock-in.

OpenTofu emerged to preserve open governance and avoid vendor tie-in, offering drop-in compatibility.

15. OpenTofu: The True Open-Source Terraform Alternative

  • Same syntax, modules, and state as Terraform
  • No vendor lock-in
  • Community-led under Linux Foundation
  • Slightly smaller ecosystem but growing fast

16. Other IaC Tools

  • Pulumi, AWS/Azure CDK, etc.: Use general-purpose programming languages for IaC. Not the core focus of this comparison but worth considering for imperative/IaC programming use cases.

17. Key Takeaways

Tool Best for Key Advantage Main Concern
Bicep Azure-focused teams Native, no state files Azure only
Terraform Multi-cloud environments Large ecosystem IBM acquisition uncertainty
OpenTofu Open-source advocates Community governance, no vendor Smaller ecosystem

Bottom line:

Choose Bicep for Azure-native simplicity, Terraform for multi-cloud maturity, and OpenTofu for open-source assurance. Each is best within its intended zone—align your tool to your team and business strategy.

This post appeared first on “Hidde de Smet’s Blog”. Read the entire article here