open-feature / open-feature/spec
Implement isolated API instances across SDKs
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@toddbaert is already working on this.
Since Apr 8, 2026.
- Dominant language
- Python
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Description
Context
The spec now supports isolated API instances; independent, non-singleton instances of the OpenFeature API, each with their own state (providers, context, hooks, events). This enables use cases like micro-frontends, dependency injection, and testing.
- Spec PR: https://github.com/open-feature/spec/pull/368
- Original issue: https://github.com/open-feature/spec/issues/359
Relevant spec sections
Requirements summary
| Requirement | Level | Description |
|---|---|---|
| 1.8.1 | MUST | Provide a factory function that creates independent API instances with their own state |
| 1.8.2 | MUST | Isolated instances conform to the same API contract as the singleton |
| 1.8.3 | SHOULD | Factory function lives in a distinct module for discoverability |
| 1.8.4 | SHOULD NOT | A provider instance should not be bound to multiple API instances simultaneously |
SDK implementation tracking
Child issues:
- Java: https://github.com/open-feature/java-sdk/issues/1925
- Go: https://github.com/open-feature/go-sdk/issues/486
- .NET: https://github.com/open-feature/dotnet-sdk/issues/734
- JS: https://github.com/open-feature/js-sdk/issues/1373
- PHP: https://github.com/open-feature/php-sdk/issues/170
- Python: https://github.com/open-feature/python-sdk/issues/584
- Swift: https://github.com/open-feature/swift-sdk/issues/115
- Kotlin: https://github.com/open-feature/kotlin-sdk/issues/229
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Assessment
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