Watching whale moves in n8n (and when I gave up and built a bot)

Description and use

The author built an automated monitoring system for large BTC transfers and wallet activity in n8n without API keys, but due to scalability and rate limits moved part of the logic to a dedicated bot and public feed.

Problem

Monitoring large BTC transfers and wallet activity without API keys, and scaling to many users and chains.

Outcome

The author achieved real‑time whale‑move alerts without API keys, but scalability and token limits prompted a split into a public feed and a dedicated bot.

Workflow

• Schedule a 2‑minute trigger
• Set configuration (thresholds, RPC URLs, chat tokens)
• Check step: fetch latest block and mempool from mempool.space, filter txs ≥ minBtc, dedupe using static data
• Check step: poll native balances via JSON‑RPC, compare to previous state, alert on change ≥ minChange
• Notify step: send formatted messages to Telegram/Discord if tokens present

Evidence

Every 2 minutes, Check looks at the newest mined block and the recent mempool, and keeps every transaction moving at least minBtc.

Source

Addresses are comma-separated in Config, with an optional label (binance-hot=0xabc…). Switch chains by changing rpcUrl.

Source

This works well for a handful of addresses. It got painful once I wanted: Many wallets, many users.

Source