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Overview

FOKS is federated: many independent servers can exist, each administered separately, but they speak the same protocol. Like email, a user on foks.app can be a member of a team hosted on corp.example.com. Users are identified as user@host pairs — e.g. alice@foks.app — so identity is scoped to the server, not globally unique. This mirrors how email works and avoids any central naming authority.

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Host Discovery

Each FOKS server has a permanent HostID — the hash of its initial public signing key. There are two ways to look up a host:
DirectionMethod
DNS name → HostIDConnect to the probe service at the DNS name; it returns the host chain and HostID
HostID → DNS nameQuery the beacon service (currently beacon.foks.pub) with the HostID to get the DNS name
This two-way lookup means a client can find a server by name or by its cryptographic identity.

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Host Chains

A host chain is an append-only signed log of key operations for a server. It establishes the authoritative history of:
  • The initial HostKey
  • Delegated keys (TLS CA, Merkle signer, Metadata signer)
  • Key rotations over time
Clients verify the host chain on first connect and check for consistency on subsequent connects. This prevents a compromised server from substituting a different key after the fact.

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Cross-Server Teams

When Alice on foks.app invites Bob from corp.example.com to her team:
  1. Alice’s client fetches and verifies Bob’s host chain from corp.example.com
  2. Bob’s public key is added to Alice’s team with the appropriate role
  3. When Bob’s client later accesses the team, it probes foks.app to verify Alice’s host chain
Servers probe each other when needed for team operations — this is handled automatically by the agent.

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Virtual Hosts

A single physical FOKS server can host multiple virtual hosts — separate FOKS instances that each have their own HostID, users, and data, but share the same underlying infrastructure. This is how foks.app works: users get their own isolated FOKS instance without needing to operate their own hardware. Virtual hosts are configured at the platform level. See Virtual Hosts for details.

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Running Your Own Server

Because FOKS is open-source and federated, you can run your own server and remain fully interoperable with foks.app and any other FOKS server. See Self-Hosting.