Our primary web application and our Slack integration both run in the cloud on top of an established Platform called Heroku, which in turn is built on top of Amazon Web Services.
Any data we store is kept either in our Postgres database (also securely hosted and managed by Heroku), or our BigQuery instance inside Google Cloud Platform. All data is encrypted at rest in both Postgres and BigQuery.
Two-factor authentication is applied to both Heroku and Google Cloud Platform.