You can configure datadog to flow alerts into Rootly following those instructions
Under Integrations > Configure webhook.
Create a rootly webhook like shown below with
Secret token is available under Rootly > Integrations > Datadog
That's how the configuration should look end to end:
Configure a minitor to notified the newly webhook endpoint created like shown below:
Under monitor > edit, you can now test your notification and make sure rootly see it in https://rootly.com/account/alerts
All set !