Young Reacts #115 – How to Pick a Product Hypothesis

Not much from me this week. Enjoy the last week of February! 😁

Software Engineering ⚙️

GraphQL Input Union is back to OneOf directives

GraphQL’s Input Union has been in the works for a long time. The first proposal was in early 2018. At this point, a lot of GraphQL users just want a solution, and I hope this proposal is it.

An interesting fact: OneOf directives are currently proposed to be applied against input objects and fields, but they could be used for the return types too. The spec working group intentionally scoped down the proposal to proceed quickly, but we will see the expansion of OneOf directives in the future. OneOf RFC Link

People ❤️

Unpacking Interview Questions

This collection of articles explains what the author looks for when asking typical behavioral interview questions such as The Weakness Question. He thoroughly discusses his motivation behind the questions, the evaluation criteria, and the typical follow-up questions, which gives the interviewees a behind-the-scenes look. I recommend reading this series if you are recruiting now.

How To Measure Engineering Effectiveness

My approach to my team’s effectiveness has been limited to “I know it when I see it.” I found it hard to assess the quality and the quantity of my team’s contribution when we are part of a larger system (product managers, designers, and other stakeholders). Measuring and getting rid of the blockers sound like a solid approach to measuring the team’s efficiency. But it still doesn’t answer if we are building the right thing. Blogpost Link

Google Fires Researcher Meg Mitchell, Escalating AI Saga

Google had suspended another AI ethics researcher, Meg Mitchell, when they fired Timnit Gebru. After weeks of investigations, they fired Meg Mitchell. Talking up diversity is easy but following through with accountability is hard. Google has done some remarkable research on psychological safety, so I am not writing it off completely, but it has lost a lot of my respect.

Business 💸

How to Pick a Product Hypothesis

Coming up with a good hypothesis for a new project is half the battle. A good hypothesis is falsifiable, measurable, and actionable. The article then gives examples of good and bad hypotheses. This article was a recommended read for an internal workshop on hypothesis thinking.

Google made a deal with Rupert Murdoch. Facebook called the bluff.

New Australian law enforces Google and Facebook to pay the news publishers to use their links on their services. Google first threatened to leave Australia (Bing selflessly offered its service in response) but cut a deal with Rupert Murdoch’s News Corp. Facebook decided not to show any news in Australia. Now the small independent outlets are squeezed between the tech and media giants. News link

Young Reacts #114 – Talent is a myth

‘Tis the recruiting season. I occasionally talk to students or recent grads who seek to enter the tech industry. Hearing their experiences is maddening. Their search for the first full-time job turns into a soul-sucking, self-esteem-destroying numbers game. They apply to dozens or hundreds of companies, and they don’t hear back from most. It upsets me that the same companies that ghost those early-career candidates would hire a team of recruiters to court the senior candidates. I wish all of us to remember what it was like to start our careers and treat the next generation with respect.

Photo by Markus Winkler on Unsplash

Software Engineering ⚙️

Stepping Stones not Milestones

When we build towards a goal over a long time with an uncertain path, we need to build and learn iteratively. But, that doesn’t mean we blindly break a 1-year long project into four quarterly goals. We need to choose the next important hypothesis and build the next Minimum Viable Product to test the hypothesis.

Attacking OSS Using Abandoned Resources

Sometimes, it takes meticulous planning and a ludicrous amount of effort to hack. And sometimes, all it takes is a Github account. Once the original owner deactivates their account, an attacker could create another project with the same username and make an unsuspecting developer install their malicious code.

Things You Can Do With CSS Today

I find it harder to stay current with CSS than with JS because CSS proposals progress and release on their own, unlike JS. So I appreciated this overview of new features.

People ❤️

Talent is largely a myth

I agree that statements like “we hire only the top 1% of developers” don’t make sense and that we need to evaluate candidates with a growth mindset. On top of that, I also believe that:

  1. Not everyone can be successful in a given environment within an acceptable time window.
  2. The hiring team’s existing effectiveness and its process is the more important factor for the candidate’s success than the candidate themself.

How We Introduced Levels to Our Engineering Organisation without Losing People or Hurting Our Productivity

Netflix famously has only one level for individual contributors. The flat hierarchy has created an environment where the best ideas, not the highest titles, win. But it has also failed to provide clarity around individual contributors’ growth. While I believe Netflix is too big to introduce levels at this point, how we could introduce them is an interesting thought exercise.

How to answer one of the toughest interview questions

That toughest question is (spoiler alert!) “How much are you making now?” Of course, it is illegal to ask this question in California. However, I will reuse the thought process when discussing my compensation expectation with recruiters or hiring managers.

Young Reacts #113

I started interviewing other engineers in my organization to understand their experience with our GraphQL implementation. I ask for a 30 min chat and come prepared with a few questions.

Among the questions, I found my last question, “Is there anything else I should have asked you?” particularly powerful. My other questions are about the things I know and care about and, thus, miss my blindspots. But this question enables the interviewees to talk about what they care about. I’ve already learned their complex authorization requirements, neighboring teams’ pushback, and the pain points around internal documentation.

When you have a chance to interview your customers or colleagues, try asking this question. You may be surprised by what you learn.

Photo by Alejandro Escamilla on Unsplash

I thank my wife, Eunyoung, for sharing this question.

Software Engineering ⚙️

Surviving the organizational side request

I haven’t experienced a rabbit hole as deep as this hypothetical one. But I wholeheartedly agree that unblocking whatever’s blocked for whatever reasons is also us engineers’ job. Link

npm 7 benchmark

Ever since npm 7 came out last October, I wanted to understand how fast npm 7 was compared to npm 6 and yarn. We finally have one benchmark, and it, unfortunately, doesn’t look groundbreaking. Some improvements with cached modules but also some regressions with fresh installs. Link

People ❤️

Incompetent people don’t know their incompetence, or do they?

The Dunning-Kruger effect can be summarized as “incompetent people don’t know they’re unskilled.” It has been cited by many articles explaining human behaviors. But a research team found that a set of randomly generated numbers could be made to look like the effect. This effect may be an excellent case of a confirmation bias. Link

What got you here won’t get you there

This^ is an important piece of advice as you want to shift into a different role. When you become a senior engineer and aim to be an engineering manager or a staff-level engineer, getting better at coding will not let you get there. We need to re-evaluate our focus based on our new objectives and changing landscapes. Link

Business 💸

Google is shifting (exiting?) its game streaming

Google first announced the game streaming platform Stadia and the internal game studio in early 2019. But in less than 2 years, it is shutting down the studio. If without exclusive games, how will Stadia compete with Microsoft Cloud Gaming or Amazon Luna, especially when these companies are doubling down on exclusive content? Link

Interview with Microsoft’s Head of Cloud Gaming

There are some interesting threads in this interview:

  1. Games are evolving from packaged goods to services to communities.
  2. New SaaS/platform opportunities for games are emerging, like renting out virtual environments for games.
  3. Game developers are evolving from AAA studios to indies to citizen developers (think Roblox).


Young Reacts #113 – Engineering Personas

The term “soft skill” implicitly undervalues interpersonal and communication skills. But these skills are in short supply and become more important as we progress in our careers.

Software Engineering ⚙️

GraphQL Schema Stitching is coming back

Schema stitching was once declared deprecated, but it has come back from the dead. I acknowledge that federation needs some complex tooling like schema validation to work well. But I am still skeptical of schema stitching. I remember that schema stitching suffered from schema merge conflicts (i.e., when two schemas define types with the same name). After looking at the doc on merging, I still see the same problem. Link

People ❤️

Engineering Personas

We are more than just “human resources.” Everyone has their preferences and aspirations, which hiring managers should consider when hiring. The article buckets engineers into five categories. While I think these categorizations are helpful when hiring, we should beware of biases and expect that people grow and change their personas. Link

AWS Compensation Explained

I was just baffled at how unintuitively the compensation works at AWS. Read the article if you are considering joining AWS. Link

Business 💸

Ethereum’s Carbon Footprint

The author researched the carbon footprint of Non-Fungible Tokens, the tokens used to create a limited number of digital goods. He found that a single transaction of an NFT produces 47 kg of CO2 on average, which is equivalent to driving 500 km. It is mindblowing. I never saw blockchain technology from this perspective, and I thank the author for his research. Link

Twitter’s New Peer Review System

On top of its existing review and recommendation system, Twitter launched a peer review system for less prominent tweets. Humans being humans, I am not sure how the system will perform for divisive tweets. I like that all generated data will be publicly available, providing visibility into the system’s vulnerabilities. Link

Young Reacts #111

One of my new year goals is to discuss my career more openly with my manager. I brought up that I want to become a manager in a year or two, and he gracefully offered me to share how he carries out his core responsibilities.

During our 1:1 Last week, he talked me through how he went about hiring for an open position on the team. There were several learnings from the discussion:

  1. Find someone who can not only do the job but also strengthen the whole team. This requires thinking about missing skills on the team.
  2. Relatedly, share and align the expectation with the recruiting teams via syncs and docs.
  3. Hiring is deemed the most important activity for a Netflix manager. One open IC position takes up 30-40% of the hiring manager’s time.

I really missed talking about leadership topics like this, and I thank my manager for this time 🙏🏼 I hope to learn how he prioritizes our product projects next time.

Software Engineering ⚙️

Conventional Commits and its niceties

Conventional Commits specifies a convention for commit messages so that both humans and machines can understand the messages. The machine-readable messages enable powerful automation. For example, at work, I can commit with a message like “fix(hierarchical-dropdown): fix hover state,” and our continuous deployment pipeline automatically increments the version and publish the hierarchical-dropdown library. Now the similar functionality is available on Github Actions thanks to Google. Link

Naming is hard

Naming variables is hard, especially for non-native English speakers. Code should be readable like prose, but that is hard to achieve when you don’t read and write English much. I wish I came up with a naming guide like this one when working in Korea, which would have helped my team. Link

People ❤️

Swinging between IC (individual contribution) and Management

Aaron Suggs was once a director, then a staff engineer, then a manager, and is now a principal engineer (remember Charity’s pendulum?). I like his criteria for choosing his role on his team (although it is a privilege to be able to choose a role):

  • What skills does the team need most acutely: management to coordinate the actions of a group; or an IC to accelerate the execution?
  • Will I have sufficient support and feedback to learn and succeed?
  • Am I the only one on the team who could do this; or could others do it well?

There are other valuable takeaways like framing his impact into “working the plan” and “serendipity” in this interview. Link

Business 💸

Google vs. Australia

The Australian government attempts to make Google and Facebook pay when they link to Australian news organizations. The same law also obliges the tech giants to use the news from those organizations. While I understand the need to ensure journalism’s survival, I am unsure if taxing Google when it forcedly links to the Australian news is the best-formulated policy. Now Google Search is threatening to leave Australia completely. Link

AWS vs. Elastic

Elastic built the popular open-source search technology Elasticsearch and the open-source visualization technology Kibana. But AWS built a competing service on those technologies which threatened Elastic’s survival. In response, Elastic has changed the two technologies’ licenses to forbid cloud providers from using those technologies to offer competing products.

Now, AWS has responded by forking Elasticsearch and creating open-sourced versions. That’s legal, of course. But such a practice discourages future venture-backed open-source technologies, which won’t be ideal for us engineers. Link

Young Reacts #110 – Take risks to grow your career

I started reading books on film making and the movie industry to better understand my team’s projects as we prioritize them (this was from my 2020 review). I’ve learned that the same titles in Hollywood and Korea do not mean the same roles from one book. I am also learning how movies have been distributed pre-Netflix based on seasonality and competition.

I got so much more excited and informed about my team’s impact that I think you should also read more about your company’s domain, even if you are “just an engineer.”

The book I am reading this week. Image from

Software Engineering ⚙️

How to communicate about tech debt

Tech debt has become that thing all ‘good’ engineers should strive to get rid of. But it’s quite the contrary. We, engineers, are hired to drive business results. So tech debt, like any other project, should be viewed and prioritized in the context of business outcomes. We should learn to explain either quantitative or qualitative business values of the tech debt work to our partners. Link

Is it possible to migrate from a cloud provider in a week?

When Parler went offline last week after AWS refused to work with the controversial service, its founder said the service would be back in a week. But is it possible? Corey Quinn, the famous cloud economist, doesn’t think so. The service hasn’t come online yet. Link

People ❤️

Take risks to grow your career

To keep growing, we need to be exposed to new challenges and learn from them. But once we get that cushy role, it is hard to get out of the comfort zone. I already feel more risk-averse since I work at Netflix — it pays well, my family is proud of me, and so on. I can’t change my roles yet anyway because of my immigration process. But will I try something new when I can? Link

“Escape your 9-to-5 job”

Gumroad is not your typical venture-backed startup. There is no hypergrowth, long hours, nor promised career growth. Even its founder is working part-time (they also pay 50% less for any hours beyond the first 20 hours). This serves as a good reminder that not all paths have to look alike, and we should choose our own lifestyle. Link

Hiring is the last resort

When work gets overwhelming, managers’ first instinct is to hire more. I’ve made that same mistake in the past. But hiring is the most expensive and slowest lever to pull and will make the organization slower to adapt in the future. Philip Fisher-Ogden (an engineering director at Netflix) recommends prioritization, optimization, and innovation before hiring. Link

Business 💸

TV is now a game console

LG’s 2021 TVs will support two game streaming platforms — Google Stadia and GeForce Now. Previously, both platforms have only been available on computers and their proprietary devices. As Phil Spencer said, TV is now turning into a game console. Link

Sports and Gen Z

Gen Z won’t sit down and watch the 2.5-hour match in full but will follow the sports stars on social media for a peek into their personal lives. Also, there is uncertainty from COVID shutting down youth sports. Link

Young Reacts #109

I am back from my trip to Korea and will be back to work this week. I am mildly excited to work again, which shows my vacation was long enough. My year begins now!

Photo by Zoltan Tasi on Unsplash

Software Engineering ⚙️

The State of CSS 2020 Report

My two takeaways:

  1. Tailwind CSS (now with Tailwind UI components) is the thing to learn.
  2. Utility CSS classes are not a minority opinion anymore.


Leveraging the TypeScript API to find issues in your code

I didn’t expect that writing a script to look at Typescript’s syntax tree could be accomplished under 100 lines of code. Something for me to try when I have tedious, mechanical refactors in the future. Link

GitHub’s WebGL Globe

GitHub launched its cool looking website with a 3D globe, visualizing Github’s activity. This article explains the visualization code line by line. Link

Iterating over iterable JS objects

During my phone screens, I see even senior candidates struggle with iterating over an object. It would be a good idea to brush up on iterations if you can only come up with forEach when you read this. (Spoiler: use for-of) Link

People ❤️

Would you discuss politics at work?

This week was marked by a series of challenging political events in the United States. Some workplaces ban the conversation around politics to avoid the pitfalls. But I personally believe acknowledging the stress on all of us and providing the space to process our feelings are the best course of action. Link

Learn to deal with uncertainty

As an engineer, I am used to immediate and clear feedback; I wait for 10 minutes, and automated tests accept or reject my work. But when I discuss long-term product roadmaps or lead cross-functional projects, there are no such mechanisms. This article helped me understand why I struggle with those high-level discussions: fewer constraints, longer feedback loops, and more high-stake problems. Link

Interviewing for Engineering Manager

I am thinking of returning to engineering management in the next year or two. Since it will be quite a big shift, I started looking at what companies look for from their engineering manager candidates. This is from Reddit. Link

News 📰

Twitter bans Trump

Twitter finally bans Trump’s account from the service after Trump used the service to encourage his supporters to storm the Capitol. I am glad that Trump won’t be able to use Twitter to seed confusion and incite violence. But Twitter is not the only social network, and other services still enable these extremists. (The alternative Twitter-like service is now suspended from app stores for the lack of content policing)

A society can’t leave its safety up to the few tech execs. The only proper way to censure and contain Trump will be through democratic institutions. Link

Young Reacts #108

I am making a formatting change to surface my reactions more clearly. Please let me know if you liked it by replying to this email.

Software Engineering ⚙️

A reasoned approach to technical changes

Successful execution in Phase 2 eventually leads to some self-propelled adoption, where people you did not explicitly sell on the new tech are freely choosing to use it.

A chief architect and a principal engineer at Slack describe how Slack makes technical changes. The defined exploration-expansion-migration process looks almost identical to how my org operates. Link

The balance between hacks and overanalysis

We have to be careful how we apply YAGNI, or You Ain’t Gonna Need It. The YAGNI mindset can make us miss significant cost savings. The right balance depends on our product’s lifecycle and will be somewhere in between. Link

AWS’s Google Maps alternative

AWS is now providing its location service like its competitors (think Microsoft Azure Maps or Google Maps). Since all my team’s infra is on AWS, this new location service is automatically a viable alternative over Google Maps. A notable backstory: Amazon, along with other tech giants, contributes to an open-source map database OpenStreetMapsLink

People ❤️

How to align now and the future

It is easy to only focus on the next project and forget the big picture.  The question“What will our product and business look like a year from now?” will keep us aligned with the long term vision. Link

How to negotiate

I am terrible at negotiating because I feel the urge to save my face. While this article is not work-related, I learned a lot about how to approach tough negotiations.

Never should one feel urgency to drop $20k+ on a rapidly depreciating asset.


Business 💸

Stock market peaks while people suffer

The lasting impact of the pandemic will be economic polarization. Folks who live paycheck to paycheck had lost their jobs when millionaires and billionaires made significant gains. This polarization will lead to more political instability in the future. Link

South Korean population started declining in 2020. What now?

Since the modern economy is based on endless growth, I’ve been worried about how the economy will behave once the population contracts. Now, this isn’t just a hypothetical in South Korea. Link

Young Reacts #107 – 2020 in Review

I spent last week looking back at 2020 and summarized my thoughts here. I definitely have things to improve (taking better care of my body and questioning more critically at work), but I am happy that I survived the year without a big personal crisis. I hope you take some time to reflect on how you fared this troublesome year.

Software Engineering ⚙️

React Server Components – Addy Osmani

The React team came out with a new experimental concept called React Server Components, which enables continuous server-side rendering (vs. one-time server-side rendering). Among the many that came out, I found Addy Osmani’s explanation the easiest to understand.

How to sell SLOs to Engineering Directors – Thomas Césaré-Herriau

At a large organization, the ability to write a compelling proposal is among the most important to have. An engineer at Brex shares his proposal that successfully persuaded his org to adopt service-level objectives (or SLO). The key is to speak in the language that the audience understands.

People ❤️

Inside the Whale: An Interview with an Anonymous Amazonian – Logic Mag

Quite a revealing piece of interview. The interview covers anything from AWS’s meteoric rise to the impact of COVID to the social justice movement at Amazon. The most memorable quote to me was, “People at Amazon are mercenaries. …People work there because it pays a little bit better than the competition and it looks good on a resume.

Moving Upstream – Aviv Ben-Yosef

This article resonated well with my 2021 goal to understand and critique more at work. If I don’t have access to the necessary context or meetings to do my job well, I need to ask for it.

Business 💸

The Loop: A community health indicator – Stack Overflow

Stack Overflow’s community management team shares how they monitor the health of their communities via metrics. I am always fascinated by how different teams use metrics to understand complex systems. If you are curious about choosing the right metrics, this article by Julie Zhuo is golden.

2020 in Review

Photo by Kelly Sikkema on Unsplash

Here is my review of 2020, the weirdest year of my life.


I had two career goals:

  • Expand my professional network
  • Embody Netflix culture


  • Led multiple cross-functional projects successfully
  • Transitioned to remote working without a hiccup
  • Had a productive Q1 and Q2 at work
  • Got used to providing positive feedback
  • Gave a public talk to a crowd of 200


  • Couldn’t understand the importance of Q3 and Q4 projects
  • Failed to get enough context on my domain to have a deep insight
  • Still not used to giving constructive feedback honestly
  • Did not expand my professional network outside the talk

Intended Changes

  • Start questioning the underlying assumptions of our projects. I am only as effective as the impact of the projects I work on. I need to make sure that they are worthy of the team’s time.
  • Make time at work to play with new technologies that I am not comfortable with.
  • Be more honest about challenging conversations and my career growth.


I had quite a few personal goals in 2020:

  • Continue to have a happy marriage
  • Rest more
  • Get leaner
  • Reach personal records on big lifts (Bench 225 lbs & Squat 360 lbs & Deadlift 405 lbs)
  • Keep up with the recent trends.
  • Read long forms vs. short forms


  • Stayed healthy throughout the year
  • Daily walks with my wife gave us more focused time with each other without devices.
  • Ran 10k in one go (first time ever!)
  • Published my newsletter every week
  • Read a couple of eye-opening books like How to Hide an Empire and Riding for Deliveroo


  • Messed up my diet and gained 5 lb while losing muscle.
  • Unable to work out as much as I wanted to due to COVID and the California wildfires
  • My sleep pattern was out of control
  • Couldn’t find the will to meditate
  • Read fewer books than I originally planned (37 out of 52)

Intended Changes

  • I’ve relied on my years of training to get away with an unhealthy diet and inconsistent sleep. I believe that reserve is now depleted. I need to start taking care of myself.
  • Accept that my life pattern has changed and adjust my plans accordingly.


I am grateful that none of my family has caught COVID-19, that my wife and I got to spend more time with each other, and that I did not have to worry about my job. I did ok considering everything.