Protocols
SAND is built on four open protocols. Each solves a different problem, and together they create a complete stack for the decentralized web.
The Four Protocols
| Protocol | Layer | Purpose | Status |
|---|---|---|---|
| Solid | Data | Decentralized storage with access control | W3C work ongoing |
| ActivityPub | Social | Federated social networking | W3C Recommendation |
| Nostr | Messaging | Censorship-resistant events | Active development |
| DID | Identity | Decentralized identifiers | W3C Recommendation |
How They Fit Together
Complementary Roles
- Solid stores your data — photos, documents, preferences
- ActivityPub shares social content — posts, follows, likes
- Nostr handles real-time events — messages, notifications
- DID identifies you — across all the above
Integration Points
| From | To | Integration |
|---|---|---|
| Nostr | DID | did:nostr uses Nostr keypairs as identifiers |
| Nostr | Solid | NIP-98 can authenticate to Solid pods |
| ActivityPub | Solid | Actors can have WebID profiles on pods |
| ActivityPub | Nostr | Ditto bridges the two networks |
Choosing Protocols
You don't have to use all four. Pick what you need:
Just Want Data Storage?
Use Solid. Store your data in pods, let apps access it.
Building a Social App?
Use ActivityPub for federation. Your users can interact with Mastodon, Pixelfed, etc.
Need Censorship Resistance?
Use Nostr. No single point of failure, no central authority.
Need Portable Identity?
Use DIDs. One identity across services.
Want It All?
Use SAND. The protocols enhance each other.
Open Standards
All four protocols are open:
- Solid — W3C Community Group, Solid Lite
- ActivityPub — W3C Recommendation (2018)
- Nostr — Open protocol, NIPs
- DID — W3C Recommendation (2022)
No company owns these protocols. Anyone can implement them.
Dive Deeper
- Solid — Linked Data pods with access control
- ActivityPub — Federation for social networks
- Nostr — Cryptographic events and relays
- DID — Decentralized identifiers