./src/bitcoind -regtest -chronik -chronikelectrumbind="[::1]:23431" -chronikelectrumbind="127.0.0.1:23430"
then:
curl --data-binary '{"jsonrpc": "2.0", "id": "test", "method": "server.ping"}' -H 'Content-Type: application/json' http://127.0.0.1:23430
curl --data-binary '{"jsonrpc": "2.0", "id": "test", "method": "server.ping"}' -H 'Content-Type: application/json' http://[::1}:23431
ninja all check-all