UnoTag

Knowledge of Node.js and frameworks available for it (such as Express, StrongLoop, etc depending on your technology stack)

Understanding the nature of asynchronous programming and its quirks and workarounds

Good with REST Api and integration of many API's in our backend

Good understanding of server-side templating languages (such as Jade, EJS, etc depending on your technology stack)

Understanding accessibility and security compliance

User authentication and authorization between multiple systems, servers, and environments
Integration of multiple data sources and databases into one system

Understanding fundamental design principles behind a scalable application

Understanding differences between multiple delivery platforms, such as mobile vs. desktop, and optimizing output to match the specific platform

Creating database schemas that represent and support business processes
Implementing automated testing platforms and unit tests

Proficient understanding of code versioning tools, such as Git
Good Code writing skills 
Integration with Shopfy, Zoho, ERP, CRM is a plus.