In July 2014, HashiCorp released Terraform, the leading infrastructure-as-code (IaC) solution. Terraform’s extensive provider ecosystem spans major cloud platforms, and developers can create custom providers to manage any API-driven service.
In March 2021, Microsoft released Bicep, a domain-specific language designed for deploying Azure resources. This marked a significant shift for Azure users for two key reasons: It simplified the complex JSON syntax of ARM templates, and it provided native integration with Azure’s tooling and security features.
Despite the existence of long-established IaC tools such as Puppet, Chef, and Ansible, Terraform and Bicep have gained strong support from the community.
The main difference between them is that Terraform is cloud-agnostic and supports multiple providers, whereas Bicep is designed specifically for deploying resources in Microsoft Azure.
In this post, we will examine both solutions and help you determine which best suits your use case.
Bicep is Microsoft’s dedicated IaC language for Azure resource deployment. It provides a declarative way to define Azure infrastructure with built-in dependency management and resource visualization.
Bicep files use the .bicep extension and provide type safety through automatic resource property validation and IntelliSense support in popular IDEs, helping catch configuration errors before deployment.
In practice, a Bicep configuration looks like this:
resource storageAccount 'Microsoft.Storage/storageAccounts@2021-06-01' = {
name: 'mystorageaccount'
location: 'eastus'
sku: {
name: 'Standard_LRS'
}
kind: 'StorageV2'
properties: {
supportsHttpsTrafficOnly: true
minimumTlsVersion: 'TLS1_2'
}
}In the above example, we’re creating an Azure storage account with a standard performance tier and locally redundant storage (LRS). The configuration specifies basic security settings, including HTTPS-only traffic and minimum TLS version 1.2. Each Bicep resource begins with the keyword resource followed by the resource type and API version, making it clear what’s being deployed.
It is important to note that Bicep files are modular by design, allowing you to break down complex infrastructure into reusable components.
Key features of Bicep
- Built-in modularity: Bicep’s module system allows you to create reusable components that can be shared across projects. These modules can accept parameters and return outputs, making them flexible building blocks for complex infrastructure.
- Stateless operations: State files are used for resource tracking and building a model of your infrastructure’s current state. Unlike other IaC tools, Bicep doesn’t require state file management. Azure Resource Manager tracks all resource states directly in Azure, simplifying deployment workflows and reducing operational complexity.
- Native Azure integration: Bicep integrates with Azure RBAC, Key Vault, and other Azure services. This native integration means you can leverage Azure’s security features and access controls without additional configuration.
- IDE support: Because Microsoft developed both Bicep and Visual Studio Code, the integration between them is exceptional. VS Code provides rich IntelliSense support, real-time validation, and syntax highlighting for Bicep files. This tight integration significantly improves the developer experience and helps catch errors early in the development process.
Why use Bicep over ARM Templates?
ARM templates (Azure Resource Manager templates) are a JSON-based configuration format used to interact with the ARM. These templates provide a consistent structure for defining Azure resources and can be pinned to specific API versions, ensuring deployment stability across update cycles.
JSON works well for small configurations, but as your infrastructure grows, you can quickly find yourself lost in nested brackets and what can only be described as indentation hell. Debugging becomes tedious, and making changes requires careful attention to maintain valid JSON syntax.
Bicep solves this by providing a developer-friendly DSL (domain-specific language). Here is a side-by-side comparison of the storageAccount resource snippet from earlier:
Terraform is an IaC, that HashiCorp developed. Terraform uses HashiCorp Configuration Language(HCL), a domain-specific language designed to describe infrastructure in a concise, readable format.
In practice, a Terraform configuration looks like this:
resource "azurerm_storage_account" "example" {
name = "mystorageaccount"
resource_group_name = "example-resources"
location = "eastus"
account_tier = "Standard"
account_replication_type = "LRS"
enable_https_traffic_only = true
min_tls_version = "TLS1_2"
}Similar to the Bicep configuration, this Terraform code creates an Azure storage account. The key difference in syntax is Terraform’s use of quotation marks around property names and the explicit resource provider prefix azurerm_storage_account. The configuration sets up the same standard tier storage with LRS replication and basic security settings.
Key features of Terraform
- Plugin ecosystem: Terraform has a rich plugin ecosystem it calls providers. These modular components enable interaction with various cloud platforms and services. Each provider, including the Azure provider, acts as a translation layer between Terraform’s configuration and the respective platform’s API, such as the ARM.
- State management: State management is at the core of Terraform’s operation. Terraform maintains a state file tracking all resources it manages, including their configurations and dependencies. This state allows Terraform to determine what needs to be created, updated, or deleted when configurations change.
- Workspaces: Terraform’s workspace feature allows you to create isolated environments for the same code. This is useful for creating separate environments that need different variables, such as pre-prod and production environments.
- Remote backend support: Terraform can store its state files in remote backends like Azure Storage, AWS S3, or HashiCorp’s Terraform Cloud. This enables team collaboration and state locking to prevent concurrent modifications and secure storage of sensitive infrastructure data.
Terraform and Bicep share a few similarities in their approach to IaC, making them both powerful tools for modern cloud deployment.
1. Developer-friendly DSL
Both tools provide a developer-friendly domain-specific language. At a glance, Terraform’s HCL and Bicep’s syntax share similarities in their declarative nature and resource definition structure — although Bicep opts for a more concise syntax by eliminating quotation marks around property names.
2. Open source community
Both Bicep and Terraform have strong open-source communities. Bicep is available under the MIT License, while Terraform recently moved to the BUSL (Business Source License).
This license change in August 2023 sparked debate in the IaC community, leading to the creation of OpenTofu — a community-driven, fully open-source fork of Terraform maintained by the Linux Foundation.
3. Strong Azure integration
Bicep and Terraform offer robust Azure support. Terraform has Azure as a first-party provider and is maintained as one of the core Terraform plugins.
Terraform and Bicep differ in a number of ways; here are a few of them:
1. State management
Terraform uses a state file to track resources and can store this state in multiple locations like Azure Storage, AWS S3, or HashiCorp’s Terraform Cloud. In contrast, Bicep requires no state management because Azure Resource Manager handles this directly, simplifying the deployment process but limiting state storage options to Azure.
2. Cross compatibility
Bicep is fully compatible with ARM templates, allowing you to compile Bicep code into them for existing codebases or deployment pipelines. Terraform doesn’t compile into other formats; instead, it uses its own deployment workflow through providers.
3. Multicloud support
Terraform supports multicloud environments, whereas Bicep is specifically designed for ARM deployments.
Terraform is cloud-agnostic, allowing users to provision and manage infrastructure across multiple cloud providers including AWS, Azure, and Google Cloud using a unified workflow. By contrast, Bicep is a domain-specific language (DSL) developed by Microsoft for deploying Azure resources, and it does not natively support provisioning resources on other cloud platforms.
4. Tooling and ecosystem
Terraform has a broad ecosystem with strong community support, a centralized registry, and integrations with many CI/CD tools. It supports multicloud environments and offers enterprise-grade tools like Terraform Cloud for collaboration and governance.
Because Bicep is Azure-specific, it is tightly integrated into Azure CLI and Visual Studio Code. Although its ecosystem is smaller and newer, it benefits from direct alignment with Azure services, ensuring fast support for new features.
5. Security and policies
Terraform offers flexible, provider-agnostic policy tooling, whereas Bicep benefits from tight integration with Azure’s built-in security and governance capabilities.
Terraform supports policy enforcement through tools like Sentinel and Open Policy Agent (OPA), allowing flexible, code-driven governance across multicloud environments. It also includes features like secure state storage, encryption, and secret management.
Bicep, designed specifically for Azure, integrates deeply with Azure Policy and Azure Blueprints, providing native enforcement of security standards and compliance rules at the platform level.
Both tools offer unique strengths for IaC deployments. For a clearer understanding of their capabilities, here is a side-by-side comparison of key features:
| Feature | Bicep | Terraform |
| State management | No state files – managed by Azure Resource Manager | Requires state file management, supports multiple backend storage options |
| Cloud support | Azure only | Multicloud through provider ecosystem |
| Cross compatibility | Compiles to ARM templates | Uses its own workflow, no cross-compilation |
| Language | Concise DSL with no quotation marks for property names | HCL with required quotation marks for property names |
| IDE support | Native integration with VS Code, strong IntelliSense | Community plugins available for multiple IDEs |
| Learning curve | Simpler for Azure-focused teams | Steeper due to broader concepts and multi-cloud support |
| Authentication | Uses existing Azure credentials | Requires separate provider authentication |
| Dependency management | Automatically handles dependencies | Requires explicit dependency declarations |
| Modularity | Built-in module system | Module support with remote module registry |
| Community size | Growing Azure-focused community | Large, established multi-cloud community |
Terraform is often preferred in multicloud or hybrid environments due to its broad provider support and mature ecosystem.
However, before you decide, a better question to ask is: what is your use case? If you’re an Azure-focused team already leveraging ARM templates, you can embrace Bicep as a better and more human-readable approach to your IaC while maintaining compatibility with your existing stack.
Terraform shines when you need to provision resources outside of Azure. Its concise syntax and community of providers and users are key benefits if Azure isn’t your only cloud.
Infrastructure automation tools in IaC, CM, and container orchestration are powerful on their own, but to leverage them, you need a CI/CD platform. While CI/CD platforms can be used to implement powerful workflows for your infrastructure, these workflows can become hard to scale, maintain, and configure beyond a certain point.
This is where an infrastructure management platform such as Spacelift comes in. Spacelift supports Terraform, OpenTofu, Terragrunt, Pulumi, CloudFormation, Ansible, and Kubernetes and enables you to see a plan of what will change after you run your infrastructure automation either via Spacelift’s UI or directly through your VCS provider.
Picnic Technologies wanted to empower its developers to create the infrastructure they needed while taking the pain out of manual Terraform processes. By using Spacelift, they have achieved this, freeing up the infrastructure team to focus significantly more on impactful work.
With Spacelift, you not only elevate the workflows for your infrastructure automation tools, but you can easily implement guardrails using policies. You can control:
- What kind of resources engineers can create, what parameters they have, and even define policies for third-party tools using plan policies
- How many approvals you need for a run and what tasks can run using approval policies
- Where to send notifications and integrate with monitoring tools using notification policies
- What happens when a PR is open or the code is merged using push policies
You can also build a multi-infrastructure automation workflow by leveraging stack dependencies and their ability to share outputs:
If your developers need to deploy infrastructure in a familiar environment, Spacelift offers self-service infrastructure via:
- Kubernetes Operator — define CRDs that deploy Spacelift resources
- Blueprints — define a YAML file that configures all the aspects related to your workflow. Developers will just need to fill in a form to provision their infrastructure.
Other features that take infrastructure management to the next level include contexts (the ability to share environment variables, files, and lifecycle hooks within your configurations), private module and provider registry for Terraform, private workers, and a resource view that shows all the resources that have been deployed with your Spacelift account.
If you want to learn more about Spacelift, create a free account today or book a demo with one of our engineers.
IaC has certainly changed how we manage cloud resources, with Terraform and Bicep emerging as powerful solutions in this space. Both tools excel in their respective domains — Bicep with its native Azure integration and Terraform with its multicloud capabilities.
For Azure-native teams, Bicep offers a streamlined path. Its compatibility with ARM templates, paired with its excellent IDE support and automatic dependency management, makes it a great choice for teams heavily invested in the Azure ecosystem.
Terraform’s strength lies in its flexibility. Its provider ecosystem and state management make it ideal for organizations managing resources across multiple cloud providers or requiring complex infrastructure orchestration beyond Azure’s boundaries.
Ultimately, the choice between Bicep and Terraform is less about which tool is superior and more about which most closely aligns with your team’s needs and infrastructure goals. Whether you choose Bicep’s Azure-focused approach or Terraform’s multicloud flexibility, both tools provide robust solutions for modern infrastructure management.
Achieve Terraform at scale with Spacelift
Spacelift takes managing infrastructure at scale to a whole new level, offering a more open, more customizable, and more extensible product. It’s a better, more flexible CI/CD for Terraform, offering maximum security without sacrificing functionality.
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