Skemaversionering

Skemaversionering is the process of managing versions of schemas that define the structure of data in information systems. A schema acts as a contract for how data is organized and validated across components such as databases, APIs, and message streams. As requirements change, schemas evolve while existing integrations must continue to operate. Skemaversionering aims to enable safe evolution through clear versioning, compatibility, and upgrade paths.

Versioning can apply at several levels, including database schemas, API payload schemas, and data formats. Versions are identified by metadata in the schema, within file namespaces, or in API paths and headers. Teams often maintain multiple versions concurrently to support legacy clients and new features.

Common approaches include backward compatibility, forward compatibility, and gradual migrations. Backward-compatible changes accept older data as well as new formats; forward-compatible changes tolerate older clients reading new data with defaults. Deprecation schedules help phase out older versions.

Governance and tooling are essential. A schema registry or repository tracks versions and metadata, while migration scripts update databases with minimal disruption. Documentation and automated tests help ensure predictable evolution.

Typical tools include OpenAPI and JSON Schema for API contracts, binary formats such as Protobuf, and database migration tools like Liquibase and Flyway. Schema registries in distributed systems enforce compatibility rules and coordinate changes.

Use cases include evolving REST APIs, event-driven architectures with versioned event schemas, and long-lived data stores that require stable data formats.