A Day in the Life: Ari Font Llitjos (Director Software Engineering, Twitter)

9 min readMar 3, 2020

Ari entered the tech industry via academic studies in Translation, Interpreting and Natural Language Processing. She since led a number of engineering, design and research teams and is currently NY Site Lead and Dir. of Engineering of the Cortex ML Platform — the central Machine Learning organization that seeks to improve Twitter by enabling advanced and ethical AI.

Ari Font Llitjos

What has been your journey in tech so far?

Having studied Translation and Interpreting (Catalan, English and German), I came to the US to do my masters in Natural Language Processing (NLP) at the Language Technologies Institute in the School of Computer Science at Carnegie Mellon University (CMU). While I had already done some programming as part of my undergrad (my senior thesis was titled: ”A bottom-up chart parser for PATR unification grammars in prolog”), it was at CMU where I really immersed myself with coding. For the first couple of years, I actually spent more time in the computer cluster than doing my graduate work. During the last years, being part of the Women@SCS grad committee was one of the greatest experiences, it allowed me to learn and grow my leadership skills.

In 2007, after defending my PhD thesis (with a 7-month baby in my belly), I joined a startup as the only Computational Linguist. In addition to doing NLP and research work, I also started becoming a more integral part of the engineering team. There, I learned and practised User Research and User Experience (UX) as well as agile and lean from the trenches (ask me about Kanban!). After a couple of years, I was speaking and facilitating workshops at Agile and Lean UX conferences, with a focus on bringing Agile and UX together.

I was leading the front-end team by the time Vivisimo got acquired by IBM. At IBM, I became Engineering Manager of my team and was part of the Design Thinking Transformation form the beginning, where we trained product teams to adopt Design Thinking and went from about 60 designers in July 2013 to 1,600 today.

A year in, I was asked to lead teams of designers and became Watson’s first Design Principal. After a one year assignment to support and learn from Mike Rhodin (Watson SVP), I joined IBM Research as Director of Emerging Technologies, where I lead a team of engineers and designers to enable researchers and help turn good ideas into impactful experiences. The best example of this was the Quantum Experience and Quiskit, which lead to the creation of a new business unit IBM Quantum. I also designed and launched what is now a Research-wide initiative (AI Challenges), which brought researchers across all global labs together to solve specific research challenges, taking an MVP approach to maximize both impact and learnings.

After 2 years, Watson recruited me back as Director of Engineering, where I ran a global organization of over 100 engineers, both in Japan and the US.

I joined Twitter almost 6 months ago, with a dual role: Director of Engineering for the Cortex Platform, leading 5 teams across the US, and NY Site Lead for over 116 engineers.

What has been the biggest challenge you’ve faced moving into your current role?

Coming in as an executive to a new organization can be tricky, since you need to very quickly get a good understanding of the culture, the teams and the technology, build relationships from scratch and, at the same time, start leading and helping the teams make critical decisions in a timely manner. And while it is sometimes quite useful to have a fresh perspective, it is equally important to also understand the context and history that has taken the teams where they are today, so that you can leverage the lessons from their past.

With so much catching up to do, ruthlessly prioritizing where I spend my time and energy is the single biggest challenge I face every day. Fortunately, the initial focus on getting to know my teams well and establishing partnerships with key stakeholders is paying off, and I have been able to start helping the leadership teams make key decisions and plan for 2020 with more confidence than past years.

Briefly describe your stack and workflow

Most of my teams use Jira for their stories, a Twitter version of GitHub for source control and Phabricator for code reviews. In addition to Python, Scalding (Twitter’s Scala library for Hadoop MapReduce jobs), React, Elastic Search, Airflow, Jupyter notebook and Manhattan (a key value pair database), most of my teams work with DeepBird v2, Twitter’s ML framework for training and serving deep learning models at scale, implemented using Python and TensorFlow in the DataRecords internal format. More recently, we’re also leveraging BigQuery and looking into Kubeflow.

We ship updates all the time, multiple per week, as we ship few lines of code, typically in the range of a couple of hundred lines, if not smaller.

Personally, I spend most of my day between Slack, Google Docs and email. For high priority initiatives, though, I use a leadership Kanban board (Jira), so that I can ensure there is somebody accountable for moving it forward, and so that we can keep an eye on our throughput and capacity as a leadership team.

Also, since one of my 2020 goals is to improve communication (we all suffer from the curse of knowledge, i.e. the cognitive bias of thinking that people know what we know), I started to share one #DailyThought every day @quicola.

What does your typical day look like?

At least 3 days a week, I wake up around 6am and take the 7am train into the city which puts me at the office around 8:30am, before most people are here.

I either meet somebody for breakfast or spend some time preparing for a full day of meetings, adding my comments to documents and answering email. Meetings usually start at 9am with several 1:1s, where I focus on that person’s challenges and needs and often turn into coaching sessions. I keep a 1:1 doc with running notes for each person I meet with, which is extremely helpful to jog my memory next time we meet, since I do end up meeting many people in one day.

One of my favorite things is Coffee Time on Wednesdays morning, where I invite all the engineers, designers, researchers and product people to join me for coffee at our speak-easy café and have a chat about anything and everything. This is a great way to meet people, especially new Tweeps. I really love the fact that not only do I get to meet everyone in a fun and casual way, but that people who have been at the office for a while and who had never talked to each other, get to connect and know each other.

I have weekly leadership team meetings, both for Cortex Platform and for the NY office, where we first go through the Kanban board and then discuss a range of topics from strategy, people and technology, and invariably how to improve the organization/site. I make sure to hold a retro every month or quarter during my leadership meetings.

For my Director of Engineering Cortex role, while there are some team members in the NY office, the majority of the team is in another office, so most of the interactions happen through slack channels, as well as through Video Conference (1:1s, leadership team meetings, working groups, etc).
For my Engineering Site Lead role, I try to meet people face to face. I also try to spend all my meals (breakfast and lunch) connecting with people and meeting them informally, so that we get to know each other as a human being, in addition to discuss work stuff.

I also have a number of other weekly meetings to advance several top priority issues. An example of this is our partnership with the Revenue org or meetings with the local team to plan future events at the NYC office, like our International Women’s Day Celebration, featuring a panel of women leaders in tech that will share how to empower and promote other women.

I am passionate about inclusion and diversity, and I really enjoy being able to bring that to both my roles at Twitter. And as much as I love solving technical problems, most of what I do nowadays is setting up success conditions for my teams, clarifying things, making decisions and resolving conflicts that arise. A key aspect of my job continues to be coaching and growing people, which is something that I really enjoy doing, and the main reason I love my job.

I try to hop back on the train around 6pm, in time to be home for dinner with Mar and Maia, my 2 daughters, and often pick up where I left it when they go to bed.

While I have to confess that I was dreading the 3+ hour commute before joining Twitter (I used to have at most a 14-minute commute when I worked at IBM’s T J Watson Research Center), this has actually become the favorite part of my day, giving me time for myself. I do use some of that time to catch up with work (like right now ;-), but most importantly, I have also figured out a morning routine that includes mindful meditation followed by tea with myself and my journal, which makes me start the day focused and ready to take on anything (thanks Micaela!). On the way back, being able to catch up with my husband when we’re on the same train, has also been a great addition to my daily routine.

What’s the best and worst part of your job?

The best part of my job is working with interesting, kind and smart people all day long, and do everything I can to gently push them out of their comfort zone and help them become the best versions of themselves.

Being able to contribute to greater inclusion and diversity at Twitter allows me to continue to work on a passion of mine that started at CMU with Women@SCS.

My job is very demanding and because I love what I do and I am inspired and driven by our mission to facilitate and increase the health of the public conversation, work does tend to take over my life. It is hard for me to switch off at home, and spend quality time with my kids in the evenings and sometimes even during the weekends. I am always working on achieving better work-life balance, but I’d say it is work in progress ;-)

What is the best piece of advice you’ve received?

“Aligning your passion with your profession” and “do your best and let life do the rest” are two of the best pieces of advice for me. The last one I recently re-learned while reading one of the books for my yoga teacher training, the Bhagavad Gita, where I was reminded to do the right thing and acknowledge that, after having done the best you could, it is no longer in your control. I am still working on the last part, both at work and in my personal life. Not expecting any results for things you care about is extremely hard, but how freeing when you manage to do it.

What is your most useful resource (book, blog, newsletter)?

You mean besides Twitter, right? I do read Twitter every day, it is my main source of news, and it helps me stay up to date despite my super busy schedule.

I am currently reading ‘Disrupt yourself’ by Whitney Johnson, which I highly recommend (thanks Helena for the recommendation!).

Another book that I find very useful for pretty much anyone, but specially if you’re not sure what you want to be when you grow up, or if you’re not loving your current job/life, is “Designing Your Life: How to Build a Well-Lived, Joyful Life” by Bill Burnett and Dave Evans.

Other all-time favorites include “Kanban” by David Anderson and “Lean Startup” by Eric Ries.

I have been eagerly awaiting every episode of the podcast “Your Undivided Attention” from the Center for Humane Technology, with hosts Tristan Harris and Aza Raskin, ever since their first episode last June.

What’s one thing you’d like to learn, develop or work on in 2020?

My biggest challenge is to find and create space for me to think, reflect and do deep work with the ultimate goal to end the year feeling less busy and hectic and being more productive and fulfilled.