# Federation Contract
For a federation to work, all providers need to come up with a federation contract to agree on. See the overview about the existing federation concepts and issues.
This contract has 2 main goals:
- Agree on interfaces and harmonization rules to align the different services in the federation.
The platform aims to be inclusive towards onboarding new features and components, to stimulate growth and innovation. To allow this in an environment that also supports user-critical workflows such functionality needs to be clearly marked, for instance by setting an 'experimental' property on a process, collection or backend, and by indicating it in descriptions or the documentation.
We assume that most often, an implementor knows when a feature is mature enough. However, when there is doubt about indicating a feature as experimental:
- By default or if unsure, it is probably experimental.
- If a feature is new or it hasn't been used, it's experimental.
- If still in doubt, consult with partner providers.
If a non-experimental component exceeds the error budget (opens new window), for instance when downtime exceeds the objective, the provider is expected to stop working on new features and improve reliability, or to mark the component as experimental. Reverting a 'stable' feature to 'experimental' should be considered a backwards incompatible change, requiring communication towards the user and proper consideration of the impact.
To join the federation, it is required to (mostly) fulfill these requirements and document differences for users in the "Federation Aspects and Known Issues". Nevertheless, these requirements are negotiable if there are good arguments for a change as the current state of the "contract" is just the compromise that the existing providers have agreed upon and if a new back-end joins the federation new compromises may need to be made.