We just love Slack
The super-fast and simple text editor, we use for everyday programming.
A solid JS core library.
We use Recurly for recurring subscription management and payments.
We use Intercom for real-time customer support and marketing automation.
We use VisualPing to visually monitor competition websites.
We use Amazon RDS as our failsafe database server system in various regions.
We use Postmark for application-specific transactional emails like notifications and digests for our users.
Our super-fast webserver.
Our analytics foundation.
We mainly use the GMail, Google Drive and Docs.
Since we don't like uptimes below 100%, we want at least to be notified when this thing happens.