How to get a list of voters for a delegate via the Core API?

A list of voters can be obtained via the Core API through the /voters endpoint and by passing a parameter username.

curl -X GET "https://node.lisk.io/api/votes?username=endro&offset=0&limit=10&sort=username%3Aasc" -H "accept: application/json"

You can also try out the request with Swagger on the Lisk mainnet