Register Chainhooks on devnet

Create predicate files

Create your Chainhook predicate files in your Clarinet project directory. You can place them in the project root or organize them in a dedicated folder.

{
  "chain": "stacks",
  "uuid": "1",
  "name": "Increment Counter",
  "version": 1,
  "networks": {
    "devnet": {
      "if_this": {
        "scope": "contract_call",
        "contract_identifier": "ST1PQHQKV0RJXZFY1DGX8MNSNYVE3VGZJSRTPGZGM.counter",
        "method": "increment"
      },
      "then_that": {
        "http_post": {
          "url": "http://localhost:3000/api/increment",
          "authorization_header": "Bearer devnet-token"
        }
      }
    }
  }
}

The predicate will trigger whenever the increment method is called on your counter contract.

Organize project structure

Structure your project with Chainhook files in a logical location. Here's a recommended project layout:

my-project/
├── contracts/
│   └── counter.clar
├── chainhooks/
│   ├── increment.json
│   └── decrement.json
├── tests/
│   └── counter.test.ts
└── Clarinet.toml

Clarinet will automatically discover predicate files in your project directory when starting devnet.

Start devnet with Chainhook registration

Launch devnet from your project root. Clarinet automatically starts a Chainhook service and registers all predicate files it finds.

$ 
clarinet devnet startCopy

Look for the registration confirmation in your terminal output:

Computing deployment plan
✔ Deployment plan completed

INFO Feb  5 15:20:07.233382 2 chainhooks registered

This message confirms your predicates are active and monitoring the local blockchain.

Verify Chainhook execution

Interact with your contracts to trigger the registered Chainhooks. Monitor the devnet terminal for execution confirmations.

$ 
clarinet console
Copy
>> (contract-call? .counter increment)

Watch the devnet terminal for triggered hooks:

INFO Feb  5 15:21:07.233382 1 hooks triggered

Your webhook endpoint or file output will receive the event payload based on your then_that configuration.