OnlineCity

We use CF for DNS hosting, since their AnyCast DNS provides the best latency in the business, and they support DNSSEC + IPv6. We don't use the CDN or website optimizations. CloudFlare

Code Coverage is an important metric for us as we aim to deliver regular improvements to our platform. Coveralls

Flask drives our APIs, both the Website APIs and the majority of the REST Messaging APIs Flask

PostgreSQL is our datastore, used for long term storage and analytics. But not active data, such as messages enroute. PostgreSQL

Chatlio enables us to communicate with customers via slack, right on our websites. Chatlio

Sentry is integrated into both the frontend UI and the backend APIs. Soon C++ too! Sentry

Our platform is based on interconnected services with a custom RPC protocol based on ZeroMQ and inspired by ZeroMQs LPP/MDP protocols. ZeroMQ

Almost all company communication happens in slack, it's the beating heart of OnlineCity. Slack

The most latency sensitive parts are written in C++. Due to our interconnected services architecture, we use either Python or C++ for each service, with the performance critical parts being C++14. C++

All data not yet commited to PostgreSQL, lives in multiple redis instances. We are heavy users of lua in redis to enable custom queue behavior. Redis