For general information on using connectors and their operations in your ESB configurations, see Using a Connector. To download the connector, go to https://github.com/wso2/esb-connectors/tree/master/sendgrid, and then add and enable the connector in your ESB instance.
Supported ESB Version
WSO2 ESB 4.9.0 supports this connector. You can download WSO2 ESB 4.9.0 from here.