Glossary
Terms used throughout this documentation, for readers coming from a different blockchain/payments background.
Fiber Network
A peer-to-peer payment channel network built on Nervos CKB. Similar to the Bitcoin Lightning Network, but with multi-asset support (native CKB, RUSD, and other UDT tokens).
FNN (Fiber Network Node)
The reference implementation of the Fiber protocol. Every participant runs an FNN node to take part in the network.
Payment Channel
A direct relationship between two nodes. Opening a channel locks CKB on-chain into a shared script; payments after that happen off-chain. Closing a channel settles the final balance back on-chain.
Invoice
A payment request, encoded as a Bech32m string (similar to a Lightning invoice). Contains an amount, asset, payment hash, expiry, and description.
Payment Hash
The unique identifier for an invoice/payment (a 0x-prefixed hex string), used to query payment status.
Shannon
The smallest unit of CKB — 1 CKB = 100,000,000 Shannon (comparable to a satoshi in Bitcoin).
HTLC (Hash Time-Locked Contract)
The security mechanism behind multi-hop payments — guarantees that either every hop in a route succeeds, or the whole payment reverts.
Multi-hop Routing
A payment doesn't need a direct channel between sender and receiver — it can route through intermediate nodes that have enough liquidity.
Liquidity
The available capacity in a channel. Inbound liquidity is how much you can receive; outbound liquidity is how much you can send. Each side reserves 99 CKB that can't be used for payments.
LSP (Lightning Service Provider)
An entity that provides payment-channel infrastructure as a service — managing nodes, liquidity, and routing on behalf of others. FiberGate does not do this — see Decisions & trade-offs for why it's a self-hosted gateway, not an LSP.
UDT (User Defined Token)
A custom token standard on CKB. RUSD (a stablecoin) is one example.
RUSD
A stablecoin on CKB testnet, supported alongside native CKB as an invoice asset.
Fiber RPC
The JSON-RPC 2.0 API exposed by an FNN node (default port 8227). Key methods FiberGate relies on: new_invoice, get_invoice, connect_peer, open_channel, list_channels.