RedMart is one of the most popular online grocery channels in Singapore. If you're selling on RedMart, here's how you can connect your account to OneCart.

1. First, you'll need to already be a RedMart merchant seller. RedMart sellers are invited to the platform, so you will need to apply and go through their approval process.

2. Once you are approved as a RedMart seller, you should request for your RedMart API key and secret from RedMart directly. You can email RedMart Partner Support at rm_partnersupport@care.lazada.com 

3. Once you receive your API Key and Secret, head over to your OneCart My Platforms account, and click "Add New". Here's a direct link for you here: https://app.getonecart.com/my_platforms

4. Select RedMart, and enter your API Key and API Secret. Once you click "Save", your RedMart account will be linked in OneCart.

You can then proceed to import and match the listings as you would any other channel.