Recycling: Why the Web is Slowing Your Mobile App

Today, nearly every website makes use of either formal or informal web APIs – from analytics to page assembly. Mobile Apps are no different. Re-using web components speeds development for web sites and apps, while helping create a consistent user experiences across multiple devices and platforms. Unfortunately there are often unintended consequences that impact performance. Separating presentation from data is a noble design objective – but be careful, here there be dragons!

Having worked with many clients on these kinds of issues, this talk will highlight the lessons learned regarding Web API and component design and how these designs impact performance, scalability and reliability. There are two primary focus areas in the talk. First is on downstream impacts of web reuse. For example, frequent, small message is useful in many cases, but load balancers that use cookies can unnecessarily triple the packet count to the application. Likewise, chaining API calls is an elegant way to modularize business rules, but what is the impact on latency and page rendering performance?

The second focus of the talk is the impact web reuse on workflows and behaviors. For example, query APIs can be long running. What are the best patterns to return pagination while preserving consistency to the dataset? Likewise, many APIs use POST by default but this (usually) will eliminate the opportunity to cache the response – which can be avoided by using a POST-302-GET callback behavior that leverages canonical destinations.

Other topics covered include:

• User session management and tracking
• Cookies, load balancers and stateless services
• Result-sets, pagination and fallback behavior
• Caching and API offload
• Workflow callback chains and browser prefetching
• Single page applications
• Presentation APIs v. Data APIs
• HTTP 2.0 v. gzip and non-SSL