neo-n3-watch

Real-time Neo N3 contract event monitor. Stream on-chain notifications straight to your terminal — no node setup, no code, just npx.

── Block 4821903 ───────────────────────────
  TX       0xabc123...
  Contract 0xef4073a0f2b305a38ec4050e4d3d28bc40ea63f5
  Event    Transfer
  Args
    [0] Hash160  = 0xd2a4cff31913016155e38e474a2c06d08be276cf
    [1] Hash160  = 0x0000000000000000000000000000000000000000
    [2] Integer  = 100000000

Why

Every Neo N3 dApp developer eventually needs to watch contract events while testing — but doing it today means either writing custom RPC polling code, running a full indexer, or staring at a block explorer. neo-n3-watch gives you a focused, zero-setup event stream in your terminal in one command.

Install

npm install -g neo-n3-watch

Or run without installing:

npx neo-n3-watch --contract 0xef4073a0f2b305a38ec4050e4d3d28bc40ea63f5

Usage

neo-n3-watch [options]

Options

| Flag | Description | Default | |------|-------------|---------| | -c, --contract <hash> | Filter by contract script hash | all contracts | | -e, --event <name> | Filter by event name (e.g. Transfer) | all events | | -n, --network <name> | mainnet or testnet | mainnet | | --rpc <url> | Custom RPC node URL (overrides --network) | — | | -p, --poll <ms> | Polling interval in milliseconds | 2000 |

Examples

Watch all NEO token transfers on mainnet:

neo-n3-watch --contract 0xef4073a0f2b305a38ec4050e4d3d28bc40ea63f5 --event Transfer

Watch all events from any contract on testnet:

neo-n3-watch --network testnet

Watch a custom contract with fast polling:

neo-n3-watch --contract 0xYOUR_CONTRACT_HASH --network testnet --poll 1000

Use a custom RPC node:

neo-n3-watch --rpc https://your-node.example.com:443 --contract 0xYOUR_CONTRACT_HASH

Default RPC Nodes

| Network | URL | |---------|-----| | mainnet | https://mainnet1.neo.coz.io:443 | | testnet | https://testnet1.neo.coz.io:443 |

How It Works

neo-n3-watch polls getBlockCount on the Neo N3 RPC every --poll milliseconds. For each new block it fetches all transactions and their ApplicationLog, then filters notifications by contract hash and/or event name and pretty-prints them to your terminal.

No indexer. No database. No websocket. Just RPC polling — lightweight and works with any public Neo N3 node.

Known Limitations

• Relies on RPC polling (not WebSocket push), so minimum latency equals the block time (~15s on mainnet)
• The RPC node must have the ApplicationLogs plugin enabled (all public COZ nodes do)
• Very high-volume contracts may produce a lot of output — use --event to narrow the stream

License

Apache 2.0 — see LICENSE

Contributing

PRs welcome. Open an issue first for bigger changes.