Quickstart

Generate a predicate file

Chainhook uses predicates to define what blockchain events to track. Generate a template predicate file:

$ 
chainhook predicates new stx-transfer.json --stacksCopy

This creates a boilerplate JSON file with the basic predicate structure. The --stacks flag specifies you're tracking Stacks events (use --bitcoin for Bitcoin).

Configure event tracking

Open stx-transfer.json and update the if_this section to track STX transfer events:

{
  "chain": "stacks",
  "uuid": "87ac9bff-1052-4d02-9c79-3768a6f08a09",
  "name": "STX Transfer",
  "version": 1,
  "networks": {
    "mainnet": {
      "start_block": 154670,
      "if_this": {
        "scope": "stx_event",
        "actions": ["transfer"]
      },
      "then_that": {
        "file_append": {
          "path": "stx-transfers.txt"
        }
      }
    }
  }
}

This predicate will:

• Track all STX transfer events (scope: "stx_event", actions: ["transfer"])
• Start scanning from block 154670
• Append matching events to stx-transfers.txt

Scan for events

Run the scan command to search historical blockchain data:

$ 
chainhook predicates scan stx-transfer.json --mainnetCopy

View results

Check the output file to see the transfer events:

$ 
head -5 stx-transfers.txtCopy

Each line contains a JSON payload with transfer details including sender, recipient, amount, and block information.