Business logic aplying design patterns, cronjobs with Python/Django, NodeJS/Express. Such as... 

Built HTTP based API endpoints (SOAP, RESTful, RPC, WebHooks and WebSockets) to be consumed by front end with User Auth, Roles & Permissions. 

API testing by Mock them with Postman or another else... 

Design/Model Database Schemas and Tables using RAW SQL or ORM libraries such as:  psycopg2 (PostreSQL), mongoose (MongoDB). 

DataBase indexing, Sharding, Replication, Normalization, Migrations, ensure High Availability (Caching), Disaster Recovery, RTO/RPO. 

Configured Security options (password & data Encryption, CSRF, JWT to avoid XSS and CSRF attacks, CORS to validate requests from recognized domains) 

Buil-it or 3rd party Middlewares configurations at:  

Application-level: 

Router-level: 

Error handling functionality: 

Security: 

Ex:  Cookies, JWT, Morgan for HTTP logs, Helmet for HTTP Header security, CORS to enable and configure cross-origin resource sharing, rate limit to limit the repeated API requests from the same IP address. 

Configured cronjobs Server Side Rendering (SSR), webpack and babel. 

Configured Cloud integrations AWS (CloudFront, IAM roles & users, EC2, S3, RDS (PostgreSQL), Lambda, SNS, EBS, VPS, ELB, SQS, ElastiCache, CloudWatch to monitor, Cognito,  CodeCommit), GCP (Firebase).  

Linux systems administration (Shell Scripting Automation, Networking, Logging/Monitoring Resources & Services).