Innovation with Constraints

One of the many paradoxes of human creativity is that it seems to benefit from constraints. Although we [perceive] the imagination as requiring total freedom, the reality of the creative process is that it’s often entangled with strict conventions and formal requirements. Pop songs have choruses and refrains; symphonies have four movements; plays have five acts; painters still rely on the tropes of portraiture. Jonah Lehrer Constraints can seem like the last thing you’d want for a creative project, but they’re actually beneficial when it comes to doing good work. [Read More]

How Does TCP Work?

The transmission control protocol (TCP) does one job very well — it creates an abstraction that makes an unreliable channel look like a reliable network. For applications built over an unreliable network like the Internet, TCP is a godsend that hides a lot of the inherent complexity in building networked applications. A laundry list of TCP features that application developers rely on every day includes: retransmission of lost data, in-order data delivery, data integrity, and congestion control. This article provides an introduction TCP, describing the structure of TCP segments, how TCP connections are established, and the algorithms that govern the flow of data between senders and receivers.

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How Do Websockets Work?

A WebSocket is a persistent connection between a client and server. WebSockets provide a bidirectional, full-duplex communications channel that operates over HTTP through a single TCP/IP socket connection. At its core, the WebSocket protocol facilitates message passing between a client and server. This article provides an introduction to the WebSocket protocol, including what problem WebSockets solve, and an overview of how WebSockets are described at the protocol level.

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The Zero Bug Policy

Building Quality into Your Process

A few years ago, a company I worked for was suffering from quality problems. We were expanding into new areas, pushing the product in new directions, and releasing new features quickly. As we pushed out new and evolved products, quality declined. Everything came to a head when customers began openly complaining about software quality. Our CTO stepped in with a mandate to solve the quality problem. His approach? The Zero Bug Policy — no-one was allowed to work on new features until the number of bugs in the product backlog was zero. [Read More]

How Does HTTP/2 Work?

Note: To make this easier to read (and write), h1 may be used in place of HTTP/1, and h2 may used in place of HTTP/2.


HTTP/1 has a long and storied history. Originally developed as a sixty page specification documented in RFC 1945, it was designed to handle text-based pages that leverage hypermedia to connect documents to each other. Typical web pages would kilobytes of data. For example, the first web page was a simple text file with web links to other text documents. Now, the web is made up of media-rich sites containing images, scripts, stylesheets, fonts, and more. The size of a typical web page is measured in megabytes rather than kilobytes, and the number of requests required to assemble a full page can be over one hundred. The reality of how web pages are built today does not match the reality that HTTP/1 was designed to support.

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Vendor Management is a Core Competency

Building and running a successful company requires an immense amount of work and talent. It also requires focus. Companies cannot try and solve problems with new and innovative techniques everywhere they operate. It is important to understand the areas your company should innovate in, and outside of that scope, use existing standards and off-the-shelf software as much as possible. There is only so much innovation that a company (or the market) is willing to bear and walking that line is a key factor in developing a successful product on time and budget. [Read More]

Overambitious API gateways

Best practices for deploying API gateways

In a microservices architecture, an API gateway can help address a number of challenges: providing a stable endpoint for clients to call, allowing an easy process for releasing new endpoints, or handling SSL termination on behalf of services, to name a few. So how do we decide what features of an API gateway to adopt, and which to leave behind? This article highlights the key functions that an API gateway can provide, suggests the scope of problem that API gateways are well-suited to solve, and cautions against the features that make API gateways too ambitious. [Read More]
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Putting the R in D

The economic limits of software development

The Research and Development department would appear to give equal weight to both research and development by virtue of naming, yet there are few engineers who would claim that research is a primary responsibility of their job. Between working on product features, planning sprints, fixing bugs, and attending meetings there is little time left for research. But what is the cost of foregoing research in favour of development? In this article, I consider the economic cost of ignoring research and argue that focusing solely on development is harmful to both product and engineering. [Read More]

Fault-Tolerance and Data Consistency Using Distributed Sagas

While microservices have become the defacto architectural pattern for building modern systems, they come with their own set of challenges. Key among them is ensuring application data consistency when data is spread over multiple databases. This article discusses one solution to this problem, distributed sagas. Distributed sagas provide consistency guarantees for systems spanning multiple databases in the face of failure using a clear and manageable implementation pattern. A saga is highly related to a finite state machines that moves consistently through a set of states, ensuring at each step that some conditions hold. [Read More]

IaaS, PaaS, SaaS and Infrastructure

Infrastructure is undergoing a significant paradigm shift. At my first job as a software developer, scaling our infrastructure meant buying a physical machine and installing it in a rack, setting up the system images and base software by hand, configuring the network using some shell scripts, and finally, making it available for developers to install software. Now, with the advent of cloud computing, the same capabilities — installing and running software — are available on-demand. [Read More]