This guide will walk you through setting up and running the Utila Co-Signer.

Prerequisites

Before running the co-signer, you must have:

A registered device.
Downloaded key shares.

If you don’t have these set up yet, follow the Device and Key Shares Setup Guide

Run the Co-Signer

The co-signer can be run in two modes:

Sign All Transactions Mode, which automatically signs all transactions designated to the service account
Webhook Mode, which signs transactions designated to the service account, based on a user-supplied webhook.

1. Run in Sign All Transactions Mode

To run the co-signer in its simplest form, which signs all relevant transactions automatically, run the following command:

./utilacli cosigner run --vault-id <vault-id> --device-id <device-id> --sign-all-txs

2. Run in Webhook Mode

To give your own service control over which transactions to sign, use the --webhook-url flag. Each transaction awaiting signature will be sent to your webhook. The co-signer will then act based on the webhook’s response.

⚠️
Don't confuse the co-signer webhook with the Event Webhooks.

Webhook Input

The webhook receives the transaction object, as defined in the GetTransaction response.

Webhook Output

The webhook must respond with:

HTTP 200 OK status code.
JSON containing a boolean field signTransaction.

Example:

{
  "signTransaction": true
}

If true, the co-signer signs the transaction. If false, it cancels it.