API versions
The API is offered as a single GraphQL endpoint at
https://data.bafu.admin.ch/api. There is no version segment in the URL
and no version request header; every client uses the current schema.
Notable changes to the schema are recorded in the version history below.
Versions follow Semantic Versioning (Major.Minor.Patch): the major
number increases on a breaking change, the minor on a new
backward-compatible feature, and the patch on a backward-compatible fix.
The version records how the schema has evolved and is not selected by
clients.
Version history
Legend: Major a breaking change that may require client updates. Minor a new, backward-compatible feature. Patch a backward-compatible fix.
| Version | Release date | Change | Description |
|---|---|---|---|
1.0.0 | 2026-07-03 | Major | Initial public release with the water.observations and water.nawa_trend datasets. |
Schema evolution
The schema is extended over time as new datasets are published. These changes are additive and backward-compatible:
- new namespaces, types and fields,
- new filter fields on existing types.
Additive changes do not affect existing queries. A query that selects an explicit set of fields continues to return those fields when new ones are added elsewhere in the schema.
The current schema can be inspected at any time through GraphQL introspection — for example via the GraphiQL Explorer.
Breaking changes
Changes that are not backward-compatible — such as renaming or removing a field or changing a field's type — are avoided wherever possible. Should such a change become unavoidable, it is announced in advance on this page so that affected clients can adapt.