Top Open-Source Tools for Cloud Architecture Diagrams

Quick Comparison

Category 1: Diagram as Code

These tools are ideal for teams that treat diagrams as code—enabling version control, code reviews, and automation in CI/CD pipelines.

Diagrams (Python)

A Python library that lets you draw cloud system architecture diagrams using code. It's one of the most popular open-source diagramming tools.

Key Features:

• Code-based diagramming: Define your architecture in Python
• 17+ cloud providers: Supports AWS, Azure, GCP, Kubernetes, and more
• Version control: Diagrams can be stored and diffed in Git
• CI/CD integration: Generate diagrams as part of your pipeline

Best for: Developers who prefer coding over manual drawing and want to version-control their diagrams.

Example code:

from diagrams import Diagram
from diagrams.aws.compute import EC2
from diagrams.aws.database import RDS

with Diagram("Simple Web Service", show=False):
    EC2("Web Server") >> RDS("Database")

Mermaid

Mermaid is a JavaScript-based diagramming tool that uses markdown-style text to define diagrams. It's integrated into GitHub, GitLab, and many other platforms.

Key Features:

• Markdown-style syntax: Easy to write and read
• Native rendering in GitHub/GitLab: Diagrams appear directly in READMEs
• Supports cloud architecture: Since v11.1.0, native architecture-beta syntax
• Multiple diagram types: Flowcharts, sequence diagrams, class diagrams

Best for: Embedding diagrams directly in documentation, READMEs, and wikis.

Example:

architecture-beta
    group api[API Gateway]
    group db[Database]
    service web[Web Server] in api
    service db_service[Database] in db
    web --> db_service

PlantUML

PlantUML is a versatile tool that uses simple text to create UML diagrams. With official AWS icon libraries, it's excellent for cloud architecture diagrams.

Key Features:

• UML and more: Class diagrams, sequence diagrams, and architecture diagrams
• Official AWS icons: Via awslabs/aws-icons-for-plantuml
• C4 model support: Document architectures using the C4 model
• Integration: Works with many documentation platforms

Best for: Teams that need precise, standardized diagrams and already use UML or the C4 model.

Structurizr

Structurizr is purpose-built for the C4 model (Context, Containers, Components, Code) using a DSL (Domain-Specific Language).

Key Features:

• C4 model focused: Designed for documenting software architecture
• DSL-based: Define architecture in a simple language
• Multiple views: Generate different diagrams from the same model
• Self-hosted option: Can be self-hosted

Best for: Teams that follow the C4 model for documenting software architecture.

Category 2: Drag-and-Drop & Manual Tools

These tools offer flexibility and control, with visual interfaces that make it easy to create, edit, and collaborate on diagrams.

draw.io (diagrams.net)

The most popular open-source diagramming tool—free, flexible, and widely used.

Key Features:

• Completely free: Open-source, no account required
• Offline capable: Desktop app available
• Extensive shape libraries: AWS, Azure, GCP, Kubernetes, and more
• Multiple storage options: Local, Google Drive, OneDrive, GitHub
• Real-time collaboration: Yes, with comment and edit features
• Export: PNG, SVG, PDF, XML

Best for: Quick, one-off diagrams, design docs, RFCs, and anything that needs a flexible manual tool.

Archibald

An open-source tool specifically designed for creating, editing, and sharing cloud architecture diagrams.

Key Features:

• Multi-cloud support: AWS, GCP, OpenShift, and more
• Drag-and-drop interface: Easy to use
• Real-time collaboration: Multiple team members can work together
• Self-hosted: Can be self-hosted for data privacy

Best for: Teams looking for a dedicated, self-hosted diagramming tool for multi-cloud architectures.

Excalidraw

A virtual whiteboard tool known for its hand-drawn style, perfect for brainstorming and early-stage design.

Key Features:

• Hand-drawn aesthetic: Great for workshops and brainstorming
• Open-source: Free and privacy-focused
• Real-time collaboration: Link sharing for team sessions
• Local-first: Data stays in your browser

Best for: Collaborative brainstorming, quick sketches, and workshops.

Category 3: Infrastructure-Aware Automation

These tools auto-generate diagrams from your live cloud infrastructure or IaC code, solving the problem of outdated diagrams.

terraformgraph

Generates interactive architecture diagrams from your Terraform configurations.

Key Features:

• Parses HCL: Analyzes Terraform configuration files
• Automatic service grouping: Groups resources by service type
• Relationship detection: Shows resource connections
• SVG/HTML output: Interactive, clickable diagrams

Best for: Terraform users who want automatic diagrams from their IaC.

StackMap

A powerful CLI-first tool that generates interactive architecture maps from live infrastructure or IaC.

Key Features:

• Multiple inputs: Live AWS accounts, Terraform state, CloudFormation templates
• Cost forecasting: Estimates cloud costs
• Drift detection: Identifies differences between code and live infrastructure
• Step Functions workflow views: Visualize Step Functions workflows
• Interactive maps: Zoomable, filterable visualizations

Best for: Platform engineers and architects needing accurate, always-current visibility.

Terramaid

Converts Terraform resources to Mermaid diagrams, enabling easy embedding in documentation.

Key Features:

• Terraform → Mermaid: Converts Terraform to Mermaid syntax
• Easy embedding: Paste into any Markdown document
• Supports multiple providers: AWS, Azure, GCP

Best for: Developers who want to embed Terraform diagrams in PRs and documentation.

KubeDiagrams

An academic project that automatically converts Kubernetes manifest files into architecture diagrams.

Key Features:

• Kubernetes → diagrams: Parses YAML manifests
• Visualizes K8s architecture: Shows pods, services, ingresses
• Simplifies complex setups: Makes K8s architecture understandable

Best for: Kubernetes developers and operators who need to understand complex deployments.

diagrams-mcp / diagram-ai-generator

AI-powered diagram generation with MCP server integration, enabling natural language diagram creation.

Key Features:

• Natural language → diagrams: Describe your architecture and get a diagram
• MCP server: Integrates with Claude Desktop and other AI assistants
• Multi-cloud support: AWS, Azure, GCP, Kubernetes
• Official icons: Uses real provider icons

Best for: Teams using AI assistants like Claude who want to generate diagrams from descriptions.

Diagrams (Python) — also covered above

diagrams-js

A TypeScript/JavaScript port of the Python Diagrams library, allowing you to define cloud architecture diagrams in code.

Key Features:

• TypeScript/JavaScript: Define diagrams in JavaScript
• 17+ cloud providers: AWS, Azure, GCP, Kubernetes, and more
• npm package: Easy to integrate into Node.js workflows

Best for: JavaScript/TypeScript developers who want code-based diagrams.

Comparison Table

How to Choose

External Resources

• Diagrams (Python) GitHub — Python library for cloud architecture diagrams
• Mermaid Documentation — Markdown-style diagram generation
• PlantUML — UML diagram generation from text
• Structurizr — C4 model diagramming
• draw.io — Free, open-source diagramming
• Terraformgraph GitHub — Terraform to diagrams
• StackMap GitHub — Interactive infrastructure maps
• AI Line Studio — $19/month for 200 diagram generations

Final Thoughts

Open-source tools for cloud architecture diagrams have become incredibly powerful. They offer everything from code-based diagramming to automated generation from live infrastructure. Each category serves a different workflow—choose the one that matches how you work.

If you prioritize automation, version control, and IaC integration, open-source tools like Terraformgraph, StackMap, and Diagrams are excellent choices. If you need a free, flexible manual tool, draw.io remains the gold standard. If you want the fastest path from idea to diagram with official cloud icons and animated exports, AI Line Studio at $19/month for 200 generations is the most cost-effective option on the market.

The key is choosing the tool that fits your workflow, not the one with the most features. And remember: with automation, your diagrams can stay current—so actually keep them that way.