Overview

A Fiber node is a running instance of the Fiber Network Node (FNN) — the reference implementation of the Fiber Network Protocol (FNP). In practical terms, it is the software that connects you to the Fiber peer-to-peer payment network, manages payment channels, routes multi-hop payments, and signs the on-chain transactions that anchor channel state to CKB.

If you want to send or receive payments over Fiber, build a wallet that speaks the protocol, or earn routing fees by forwarding payments for others, you need a node.

What a Fiber Node Does

Running a node gives you a local view of the Fiber network and the ability to:

• Maintain payment channels — open, update, and close channels with other nodes.
• Send and receive payments — both direct peer payments and multi-hop routed payments.
• Swap assets — move value across CKB-native assets (CKB and whitelisted UDTs such as RUSD) and across networks (e.g., between Lightning and Fiber via cross-chain constructs).
• Route payments — forward payments for others and collect routing fees if you run a well-connected public node.
• Gossip with the network — discover peers, channels, and fee policies through the P2P protocol.

All of this happens through a JSON-RPC interface (and an optional CLI wrapper). The node itself is responsible for channel state management, HTLC/PTLC-style locking, and publishing the correct on-chain settlement transaction when a channel closes.

Node Forms

Fiber ships in two forms. The right one depends on where you want to run it and who controls the runtime.

Native Node (fnn)

The native Rust binary is the full production node. It runs as a standalone process on a server or local machine, stores channel state locally (RocksDB or SQLite), and exposes JSON-RPC on 127.0.0.1:8227 by default.

Use the native node when you need full control, persistent storage, and the ability to accept inbound channel requests from the public internet.

→ Run a Native Node

WASM Node (fiber-js)

fiber-js compiles the same node logic to WebAssembly so it can run inside a browser or a Node.js process. It stores data in IndexedDB (via a WASM worker) and is designed for client-side applications that do not want to operate a backend server.

Use the WASM node when you want users to bring their own node inside a web app, without asking them to install or host server software.

→ Run a WASM Node

Deployment Scenarios

Local / Testnet Node

The fastest way to experiment. You run fnn locally against Fiber Testnet, fund the address from a testnet faucet, and open channels with the public Testnet relay nodes. No public IP is required because you initiate outbound connections to the public nodes.

Typical flow:

1. Download or build the fnn binary.
2. Generate or export a CKB private key.
3. Copy config/testnet/config.yml and set FIBER_SECRET_KEY_PASSWORD.
4. Start the node and connect to a public Testnet node.
5. Open a channel and try Basic Transfer.

Production Public Node

A public node has a reachable P2P address (default port 8228) and is advertised in the network graph. Other nodes can connect to it and open channels. This is the form you want if you intend to:

• Accept inbound channels from users.
• Route multi-hop payments and earn fees.
• Provide liquidity as a service.

You will need:

• A stable server with a public IP.
• A trusted CKB RPC endpoint (especially important on Mainnet).
• Sufficient CKB/UDT liquidity to fund and maintain channels.
• (Optional) A TLS proxy if you also want browser/WASM clients to reach you over WSS.

→ See WSS Configuration for browser-facing deployments.

Private Node Behind Relay

Not every node has to be public. A private node can open outbound channels to public relay nodes and then send or receive payments through those relays. This is the easiest way to participate without exposing a public IP or running server infrastructure.

This pattern is covered in the Public Nodes User Manual and is the default mental model for the WASM node.

Browser-Embedded Node

With fiber-js, a Fiber node can live inside a web page. Application code creates a Fiber instance and starts it with fiber.start(config, fiberKeyPair, ckbSecretKey, ...); the node can then connect to Testnet bootnodes over WebSocket. This is ideal for wallets, games, and demos where installation friction must be minimal.

→ Run a WASM Node

Mainnet vs. Testnet

Fiber supports both Mainnet and Testnet deployments. The network is selected in config.yml via the fiber.chain field.

Testnet is the recommended place to start. Once you are comfortable with channel management, payment flows, and backup procedures, move the same setup to Mainnet.

Before You Start

At a minimum, you need a CKB private key. You can generate one with ckb-cli or export it from a CKB wallet.

The detailed prerequisites — CKB RPC endpoints, config.yml, how much CKB to reserve, and whether a one-way channel lets the other side join without depositing CKB — are covered in the native and WASM guides linked below.

Choose Your Path

After you have a node running, continue with Basic Transfer to send your first payment.