Backstage vs PF4J

Backstage is a free, open-source framework for building and deploying developer portals. Its software catalog records ownership and metadata for services, websites, libraries and data pipelines, for teams managing a small set of services or company catalogs of thousands. Software Templates can fill code skeletons with variables and publish generated projects to destinations such as GitHub or GitLab. TechDocs keeps documentation in a docs-like-code workflow close to code. Integrations can read or publish data through GitHub, GitLab, Bitbucket, LDAP and cloud providers. Teams can extend a portal with existing open-source plugins or build their own; Backstage Search can index sources such as TechDocs, Confluence and Stack Overflow. Its Kubernetes feature aggregates a service’s deployments through the Kubernetes API. Backstage is self-hosted. The standalone installation guide creates a local demo with an in-memory SQLite database and says this setup is not production-ready. It lists minimum requirements of 20 GB disk and 6 GB memory, with more disk needed as modules and plugins are added. Its threat model describes only rudimentary denial-of-service protection and recommends a protected deployment environment.

PF4J has no write-up on Specifiction yet; its figures are above.