Like holiday music, lists are a seasonal cliche. They pique our interest year after year because we want a tl;dr for the 12 months gone by. To summarize, Mozilla Hacks celebrated its 10th birthday this past June, and now in December, we come to the end of a decade. Today, however, we’ll focus on the year that’s ending.

Topics and patterns

In fact, we covered plenty of interesting territory on Mozilla Hacks in 2019. Some of our most popular posts introduced experiments and special projects like Pyodide, extending the web platform for the scientific community. Mozilla WebThings, which also featured as one of 2018’s most popular posts, continued to engage attention and adoption. People want a smart home solution that is private, secure, and interoperable.

Not surprisingly, interest in Firefox release posts is stronger than ever. Firefox continues to deliver new developer tools and new consumer experiences to increase user agency, privacy, security, and choice — and our readers want the details.

Also, we’ve made remarkable progress on WebAssembly, as it extends beyond the browser and off the Web, via WASI (WebAssembly interface types) and associated tooling. Mozilla is a founding member of the Bytecode Alliance. Announced last month, this open source initiative is dedicated to creating secure new software foundations, built on new standards such as WebAssembly and WebAssembly System Interface (WASI). Plus, readers can’t get enough code cartoons, especially for visualizing complex concepts in programming.

The 2019 list

Some of the most high-traffic posts of 2019 were written in earlier years, and continue to attract readers. These are not included here. Instead, we’ll focus on what was new this year. And here they are:

1. Pyodide: Bringing the scientific Python stack to the browser, by Michael Droettboom. On the heels of Project Iodide, this post describes Mozilla’s experimental project — a full Python data science stack that runs entirely in the browser.
2. Standardizing WASI: A system interface to run WebAssembly outside the web by Lin Clark. WebAssembly needed a system interface for a conceptual operating system, in order to be run across all different OSs. WASI was designed as a true companion to WebAssembly, upholding the key principles of portability and security while running outside the browser. Code cartoons included.
3. Introducing Mozilla WebThings. In this April post, Ben Francis announced the next phase of Mozilla’s work in IoT. The Mozilla WebThings platform for monitoring and controlling devices over the web consists of the WebThings Gateway, a software distribution for smart home gateways, and the WebThings Framework, a collection of reusable software components.
4. Firefox’s New WebSocket Inspector. Recently, Jan “Honza” Odvarko and Harald Kirschner introduced Firefox DevTool’s Websocket Inspector, a much requested feature for visualizing and debugging real-time data communication flows.
5. Implications of Rewriting a Browser Component in Rust. In the closing post of her Fearless Security series, Diane Hosfelt uses the Quantum CSS project as a case study exploring the real world impact of rewriting code in Rust.
6. Technical Details on the Recent Firefox Add-on Outage. Firefox CTO and Levchin Prize winner Eric Rescorla tells it like it was. After all, who doesn’t love an in-depth, blow-by-blow post-mortem.
7. Firefox 66 to block automatically playing audible video and audio by Chris Pearce. Unsolicited volume can be an annoying source of distraction and frustration for users of the web. Accordingly, in Firefox 66, the browser began to block audio and video from playing aloud until the user has initiated the audio. Firefox uses the HTMLMediaElement API to make this work.
8. The Baseline Interpreter: a faster JS interpreter in Firefox 70 by Jan de Mooij. Meet the Baseline Interpreter in Firefox 70! Instead of writing a new interpreter from scratch, the JavaScript engine team added a new, generated JavaScript bytecode interpreter by sharing code with our existing Baseline JIT. Here’s how.
9. Faster smarter JavaScript debugging in Firefox DevTools. Who wouldn’t want to run faster and smarter?! Especially where debugging is concerned. Firefox DevTools product guy Harald Kirschner describes in detail.
10. WebAssembly Interface Types: Interoperate with All the Things!. People are excited about running WebAssembly outside the browser, and from languages like Python, Ruby, and Rust. No doubt about it. We round out the top ten with Lin Clark‘s illustrated look at WebAssembly Interface Types, and the proposed spec to make it possible for WASM to interoperate now and in future.

…And a happy new year!

Thank you for reading and sharing Mozilla Hacks in 2019. Here’s to the amazing decade that’s ending and the new one that’s almost here.

It’s always a good year to be learning. Want to keep up with Hacks? Follow @MozillaDev on Twitter, check out our new Mozilla Developer video channel, or subscribe to our always informative and unobtrusive weekly Mozilla Developer Newsletter below.