Model your software

Published on April 23rd, 2022


Backstage, the open source project upon which Roadie is built, has an opinionated stance on the structure of a software catalog. We’ve built some flexibility into that model, but at it’s core we still maintain concepts of: entities, kinds, relations and types, all stored in metadata about a given entity.

Catalog Entities

Each catalog item in Roadie is referred to as an “entity”.


Roadie supports a few main kinds of entity:

Business or ‘ecosystem’ kinds, which model the organisational context in which software is created:

  • Domains - a collection of entities and Systems that form some distinct part of your organisation;
  • Systems - a collection of different entities that have a set function.

Software kinds, which model the individual elements of your software:

  • Components - for example a website or a data pipeline. Components can be traced in source control or represent some open source or commercial product.
  • APIs - attached to components but a first-class citizen of the data model, APIs form the boundaries between Components.
  • Resources - pieces of infrastructure required by Components.
  • Repositories - source code representations of other entities, often created automatically when a source code management tool like GitHub is connected to Roadie.

And ownership kinds, which model

  • Users - a person
  • Groups - a team, an interest group, or a part of the organisation that you wish to demarcate.

There is also a special kind called Locations which provides a reference by which Backstage looks for catalog data.


Entity kinds are associated with one another using entity relations.

System Model

Relations are relatively flexible and Kinds can relat to other kinds if you so wish. For example, if you have want to represent Domains that are children of other Domains that is possible.

Relations are represented in the catalog-info.yaml files for a given entity

  // ...
  relations: [
      type: ownedBy
      targetRef: group:default/developers


You can also assign types to each entity as you see fit. Types are user-defined and can be used as you see fit.

Types may include:

  • Website;
  • Database;
  • or Library.

Other metadata

Reserved fields

A number of fields are reserved with special meaning:

  • name
  • namespace
  • uid
  • title
  • description
  • labels
  • annotations
  • tags
  • links

More details can be found in the Backstage docs.

Adding your own data

The metadata object is currently left open for extension. This often allows the storing of useful information about a given entity that can then be rendered in the Roadie UI. For example,

  // ...
  metadata: {
    name: teachers,
    purple-monkey: dishwasher
    // ...