Option A: webhook push
Register an endpoint onwhale_trades_inserted and verify it. Full setup, signature verification, and retry handling are in the Webhooks guide. The event tells you new trades landed; fetch the detail and filter:
min_size and min_grade filter on the fetched trades.
Option B: polling
No public URL required. Walk the durable replay feed with a cursor so you never miss or double-count an event across restarts:GET /api/v1/whale-trades with your filters, or open the SSE stream for real-time push without a webhook.
Post the alert
Which to choose
Webhooks win when you have a server and want the lowest latency. Polling the cursor feed wins for a script, a notebook, or anything behind NAT.