Niklaus Wirth (remember Pascal and Modula?) wrote a paper back in 1995 issuing a Plea for Lean Software. He starts by stating a fact that has remained true in the desktop world since then:  “Memory requirements of today’s workstations typically jump substantially whenever there is a new software release. When demand surpasses capacity, it is time to buy add-on memory; when the system has no more extensibility it is time to buy a new, more powerful workstation”.  And then he poses the question that is discussed in the paper: “Do increased performance and functionality keep pace with the increased demand for resources? Mostly the answer is no”. Today, 22 years later, we have a seemingly completely different reality, but we still can observe the consequences of Wirth’s statement in the harsh challenges involved in attaining highly performant mobile websites; there is a performance problem in the mobile web that needs to be solved.

In essence, we need to solve an optimization problem with three main dimensions:

  1. User Experience (UX): Engagement and delight using apps
  2. Developer Experience (DX): Ability/ease to develop apps
  3. Monetization Experience (MX): Monetization goals.

If we care only about UX, then developers may have to work at the lowest levels of abstractions to achieve the highest speeds, and publishers will make less money by interrupting the user the least with ads and monetization strategies. If we care only about DX, then users will likely  experience slowness from bloated/inefficient websites, and publishers will make less money because a decreased level of user engagement. If we care only about MX, then users will get annoyed with intrusive ads, and developers will be forced to implement aggressive monetization strategies. What we need is, at least, an approximation to an optimal solution to a 3D optimization problem that strikes the proper balance between UX, DX, and MX.

The common factor across these three dimensions is performance. Users want fast websites (UX), which leads to higher engagement and higher ROIs (MX), and developers of apps and frameworks want to design and develop fast products effectively (DX).

This essay argues about the need and approach to building for performance that drives the developing and evolution of mobile websites: the importance of performance in UX and MX, the role DX plays in the overall equation, and a suggested approach for thinking about and analyzing the performance of mobile sites.  The target audience is two-fold: (1) Web Developers; the community who makes design and implementation decisions; and (2) Decision makers; the community who decides what are the most important features and constraints. The goal is to define common grounds to think about performance so that we can reach the best solution to our three-dimensional optimization problem.

Specifically, we want to discuss:

  1. What is performance?
  2. What are the elements of Performance?
  3. Why is attaining high performance hard?
  4. What are the right performance metrics and budgets?
  5. What tools can we use to measure performance?
  6. What is the best performance testing environment?
  7. How do good performance strategies look like? [patterns]
  8. How do I go about analyzing the performance of sites? [methodology]
  9. How can I learn more about this?

Much of the content mentioned, described, and analyzed in elaborating our perspective in this series of articles can be (and has been) found scattered across many resources such as books, online videos, external online courses, internal documents, product documentations, internal performance trainings and presentations, etc. As Wilson Mizner said: When you steal from one author, it is plagiarism; when you steal from many, it is called research. Well, consider this guide the outcome of our research on the performance of mobile websites.

In the next post we ask the question: what is performance?