# WebID
**WebID** is a decentralized identifier standard that uses HTTP URIs to uniquely identify users on the web. It's a foundational component of [[Solid]] and the [[Solid Protocol]], enabling self-sovereign identity without relying on centralized providers.
## Key Characteristics
- **Globally Unique**: Each WebID is a unique HTTP URI (e.g., `https://alice.example.com/profile/card#me`)
- **Dereferenceable**: The URI resolves to a profile document containing the user's public data
- **Decentralized**: Users own their identifier; no central authority issues WebIDs
- **RDF-based**: Profile documents use RDF (typically Turtle) for semantic interoperability
- **Linked**: Profiles can reference other WebIDs, building a web of trust
## Profile Document
A WebID Profile contains:
- Public key information for cryptographic verification
- Personal metadata (name, friends, preferences)
- Storage locations (pod URLs)
- Authentication endpoints
- Extensible via RDF vocabularies (FOAF, Schema.org, etc.)
## Authentication Methods
- **WebID-OIDC** (now [[Solid OIDC]]): OpenID Connect-based authentication
- **WebID-TLS** (legacy): Client certificate-based authentication
## Use Cases
- User identification across [[Solid]] applications
- Authentication without passwords or centralized identity providers
- Building decentralized social networks
- Cross-platform data ownership
## Resources
- W3C WebID spec: https://www.w3.org/2005/Incubator/webid/spec/
- WebID at solidproject.org: https://solidproject.org/users/get-a-pod
- Developer guide: https://dev.solidproject.org/
## References
- https://www.w3.org/2005/Incubator/webid/spec/
## Related
- [[Solid]]
- [[Solid Protocol]]
- [[Solid OIDC]]
- [[Web Access Control (WAC)]]