[Home](./index.md) > [@firebase/storage-types](./storage-types.md) > [SettableMetadata](./storage-types.settablemetadata.md) > [customMetadata](./storage-types.settablemetadata.custommetadata.md) ## SettableMetadata.customMetadata property Additional user-defined custom metadata. Signature: ```typescript customMetadata?: | { [key: string]: string; } | undefined; ```