Backstage

Backstage is Spotify's open-source developer portal framework providing a service catalog, software templates, TechDocs (docs-as-code), and a plugin architecture for building comprehensive internal developer platforms. Its Catalog API gives agents programmatic access to the organization's service inventory — ownership, dependencies, APIs, and metadata — making it a valuable integration point for agents that need to understand the software landscape. For platform engineering teams, Backstage is becoming the standard internal developer portal that agents can query for organizational context.

The Catalog API (REST) provides access to entities (services, APIs, resources, users, groups) with their metadata, ownership, and relationships. Agents can query the catalog to find service owners, discover API dependencies, retrieve TechDocs content, and create new services from software templates. The Scaffolder API enables programmatic service creation from templates — agents can spin up new microservices with standard configurations.

Authentication supports multiple identity providers (GitHub, Google, Okta, custom) and the permission framework provides fine-grained access control for catalog entities and plugin features. Self-hosted Backstage instances manage authentication configuration. The permission system enables different agent roles (read-only catalog access vs. template execution).

Reliability for self-hosted Backstage is the team's operational responsibility. Backstage runs on Node.js with PostgreSQL and requires appropriate production hosting. The catalog ingestion pipeline (reading entity definitions from Git repositories) needs monitoring for freshness. The plugin architecture means reliability depends on the specific plugins deployed.

Documentation is extensive and covers the catalog, scaffolder, TechDocs, and plugin development. The catalog entity model documentation is the most important reference for teams building catalog integrations. Teams adopting Backstage should invest in understanding the entity model and relationship types — the catalog is most valuable when it accurately reflects the organization's software landscape.