[API reference](https://evolu.dev/docs/api-reference) › [@evolu/common](https://evolu.dev/docs/api-reference/common) › [Lookup](https://evolu.dev/docs/api-reference/common/Lookup) › StructuralLookupKey

```ts
type StructuralLookupKey = string & Brand<"StructuralLookupKey">;
```

Defined in: [packages/common/src/Lookup.ts:264](https://github.com/evoluhq/evolu/blob/037c390af081e9944d616ff298a729515c5c5ab7/packages/common/src/Lookup.ts#L264)

Branded native key produced by [structuralLookup](https://evolu.dev/docs/api-reference/common/Lookup/functions/structuralLookup).