Gatsby Logo

ARC42 Architecture


Arc42 is a template for architecture communication and documentation.

"Arc" is for Architecture, and "42" is based on the book "Hitchhikers Guide to the Galaxy", by Douglas Adams, where "42" is the

“answer to the meaning of life, the universe, and everything”

While Arc42 may not have the “answer to the meaning of life, the universe, and everything”, it does answer the following two questions in a pragmatic way

  • What should we document/communicate about our architecture?
  • How should we document/communicate?

And it can be tailored to your specific needs.



The Template architecture doduments are available for download in many formats.

The template is guided documentation with tips.


The arc42 documentation template aligns with the C4 model. The diagrams map as follows:

Arc42 C4
Context and Scope System Context diagram
Building Block View (level 1) Container diagram
Building Block View (level 2) Component diagram
Building Block View (level 3) Class diagram


Cover Title
[ARC42 by example]( arc42 Software Architecture Documentation in Practice: Real software architectures, documented with the arc42 template. Helps you jumpstart your own documentation.


Related material:

Item Details
Documenting Software Architectures Book: Documenting Software Architectures: Views and Beyond (2nd Edition) 2nd Edition
docToolchain Tool: docToolchain is an implementation of the docs-as-code approach for software architecture plus some additional automation. The basis of docToolchain is the philosophy that software documentation should be treated in the same way as code together with the arc42 template for software architecture.