What does a modern web app usually need:
- support localization in frontend and backend
- reliable background worker queue system
- content caching system
- client-polling / server-push system
- full-text search system
- user authentication system
- user access control system
- rich front-end framework (reliable on flanky network)
- user action queue
- retry user action
- Web API client (with auth, cache, retry, background work supports)
- Web API provider (auth, api doc, JSON view templating, cache control)
- User analytics
API Error Response Format
http://tools.ietf.org/html/draft-nottingham-http-problem-04
https://github.com/guillec/api_problem