How to Crack System Design Interviews - Part 6: Mock Interview

This video demonstrates a system design interview for analyzing Snapchat filter usage. We are tasked with designing a system to track and analyze filter usage data for executives and product managers. Here's what we do:

- **Gather requirements:** We clarify the scope of the system, including the number of filters, their dynamic nature, and the desired metrics (daily, weekly, monthly usage, and potentially hourly breakdowns).

- **Design the system:** We propose a write-heavy system with separate read and write paths to optimize performance. The write path handles incoming events from users, while the read path aggregates and transforms data for querying.

- **Consider scalability:** We discuss sharding and using a write-optimized database like Cassandra to handle the high volume of incoming events.

- **Address data aggregation:** We explore using Apache Spark to process and aggregate data based on time and user demographics, storing the results in a database like DynamoDB.

- **Differentiate query types:** We propose separate APIs for common, pre-aggregated queries and custom queries, acknowledging the potential latency differences between the two.

[Gaurav Sen](https://www.linkedin.com/in/gkcs/) has conducted 1000s of system design interviews while working at Uber and building his [YouTube channel](https://www.youtube.com/@gkcs) to 500K+ subscribers. His platform [InterviewReady](https://interviewready.io/?_aff=JOINTARO) combines video explainers, live Zoom classes, and an automated System Design Judge.

Write A Stellar Resume As A Software Engineer [Part 5] - Resume Gaps

Having an employment gap is effectively inevitable as a software engineer, especially in a layoff-economy. This leads to resume gaps, which unfortunately have a lot of stigma. This lesson teaches you:

- Why employers (rightfully) hold resume gaps against you
- How to include your resume gap on your resume
- What to do in common resume gap scenarios if a company probes you about it during an interview

If you have recently been laid-off, you can check these out as well: [\[Taro Top 10\] Navigating Tech Industry Layoffs](https://www.jointaro.com/playlist/pE7pP0nXDx4X7mOChzHS/)

Build Deep Relationships Quickly In Tech [Part 3] - The #1 Rule Of Networking

Many engineers struggle with networking as they don't fundamentally understand how it's supposed to work. This lesson teaches you:

- The #1 rule of networking and how not following it completely messes up your social circle
- A very tactical, mathematical framework from which to view networking
- How giving more than you take creates an infinite amount of value
- Why you're not a "loser" for being benevolent and kind
- The pain and toxicity of being in a fake network, which many engineers are a part of
- The powerful benefits of being in a true network

Maximizing a Severance Package 5/9 - Preparing Your Case

Let's talk about how to prepare your case to maximize your severance package.

- Connect with [Ethan on LinkedIn](https://www.linkedin.com/in/ethanevansvp/)
- Taro members get a discount to join [**Ethan's Level Up community**](https://levelupwithethanevans.substack.com/taro25)

20 Years Of Fighting Procrastination [Part 7] - Just One Thing

Break Into Tech And Become A Software Engineer [Part 4] - Why Foundation Is Crucial

In this lesson, Brian emphasizes the importance of building a strong technical foundation in order to succeed long-term in the tech industry.

This lesson covers:

- The risks of becoming a "framework developer" without understanding core programming concepts, which can jeopardize career stability
- Brian’s personal experience of having to attend two bootcamps to fill in gaps in foundational knowledge, despite already being in the industry
- The importance of understanding the underlying technologies, not just frameworks, to boost both career growth and confidence

If you need extra help breaking into tech, join Brian's exclusive, cohort-based bootcamp (just 10 students per batch). Use this special link for $800 off: <https://www.parsity.io/taro>

Connect with Brian on LinkedIn: <https://www.linkedin.com/in/brianjenney/>

Failure Mode: Excessive Handholding

A common failure mode of onboarding is that, even 6 months into the job, the engineer still needs support to make code changes. Either with their workflow or a technical question about the code.

The sign of progress as you ramp up is if your questions and code reviews are evolving over time. The types and depth of interaction you have with coworkers should change.

The key to doing this is to reflect:

- Look at earlier code comments you received
- Write down questions you’ve had
- Don’t make the same mistake twice
- Ask your onboarding buddy to look for patterns

Reference question: [What does it mean to not require handholding anymore?](https://www.jointaro.com/question/5vEWajcZlSi7nlohTGtJ/what-does-it-mean-to-not-require-handholding-anymore/)

Nail Your Promotion As A Software Engineer [Part 5] - Underleveled? It's A Feature, Not A Bug

You're doing better than almost all other engineers at your current level, at least the ones you can easily compare yourself to. So why aren't you getting promoted? Well, it might actually be dangerous to do so. This lesson teaches you:

- Why if a company is doing promotion properly, getting to the next level always involves fundamental behavior change
- The Peter Principle and how it explains the danger of promoting engineers based on their mastery of their current level
- What lagging promotion is and why it's important, both for you and the company
- A framework to understand what it means to go from one level to the next, paired with an in-depth example of the mid-level to senior transition

If you want to learn more about the concrete differences between engineering levels: [\[Taro Top 10\] Understanding Engineering Levels](https://www.jointaro.com/playlist/e9rjATPbSyvRPsukXiHn/)

Maximize Your Productivity As A Software Engineer [Part 12] - Just 1 Thing

As a software engineer, it is incredibly easy to get overwhelmed with the sheer amount of tasks on your plate. This lesson teaches you:

- What you need to do every single day to give yourself the gift of focus and be productive
- What to do if you absolutely need to get multiple major tasks done in a day
- How to enforce your focus on your singular task by systematizing it

Level Up Your Code Quality As A Software Engineer [Part 15] - Make It A  Little Better Each Time

We all want to make big, fast strides, but this is often hard to actually achieve. When it comes to leveling up your code quality, a lot of the battle is incremental. This lesson will teach you:

- A framework you can apply to your code repeatedly to make it better and strengthen your coding skills
- How small improvements here and there can really add up over time to increase the quality of a codebase and build up your respect among the team
- An organic trick that Alex and all his mentees used at Meta to strongly succeed on the technical axis and get promoted fast

Maximize Your Equity And Benefits In Tech [Part 2] - The Big Picture

Equity compensation can be a powerful but complex part of your total rewards in tech. Here are the core points from the lesson:

- Startup equity is high risk, with data showing over 60% of startups from 2018 have already shut down, and only a tiny fraction have reached IPO or unicorn status
- Multiple cognitive biases—like endowment effect, loss aversion, and optimism bias—can cloud judgment and lead to poor decisions about holding or selling stock
- Emotional and social factors, such as FOMO, herding behavior, and recency bias, often push people to mirror peers rather than make rational equity decisions
- Selling strategies can range from immediate liquidation to goal-based triggers (e.g., home down payment), percentage-based sales, or predefined holding periods
- It's crucial to plan ahead, especially around liquidity events, and work with financial professionals to optimize tax implications and align decisions with personal goals

Next steps with Andy:

- [Connect with Andy on LinkedIn](https://www.linkedin.com/in/andymoranio)
- [Leave feedback and/or sign up for Andy’s newsletter](https://subscribepage.io/taroequitycourse)
- [Schedule a consultation](http://adastrafp.com/contact-us/)

Master The Behavioral Interview [Part 16] - Senior Engineer

Senior engineers are proven leaders who make the engineers around them better. "Senior" is a badge of honor that almost all engineers strive for after entering the industry. This lesson teaches you:

- The expectations from a senior engineer overall and how that reflects in behavioral interviews
- The kinds of stories senior engineers tell in behavioral interviews

Ace Your Tech Interview As A Software Engineer [Part 11] - Struggling? Send More Applications

One of the most common reasons for a struggling software engineer job search is that they simply aren't applying enough. The good news is that this can be easily fixed with the proper behavior adjustments. This lesson teaches you:

- How you can conquer the job search with sheer math
- A healthy conversion rate for application -&gt; interview chance
- Why you should almost never spend too much time on any individual application (quantity &gt; quality)
- The framework to follow on whether you should apply a ton or apply more selectively

Here are the Big 2 job searching websites:

- <https://www.linkedin.com/jobs/>
- <https://wellfound.com/>

On top of the Big 2, we've seen engineers have success with:

- <https://otta.com/>
- <https://www.workatastartup.com/> - Jobs at Y Combinator startups specifically, the greatest incubator in the world which is behind Stripe, DoorDash, Airbnb, and many more FAANG-adjacent companies

3 Quick, Powerful Negotiation Tips

Negotiating pay can feel intimidating, but it’s one of the highest-leverage actions you can take in your career. These strategies highlight how to be persuasive, respectful, and ultimately successful in maximizing your offer.

- **Be kind but firm**: It’s possible—and important—to express appreciation for the opportunity while making clear that thoughtful evaluation and proper compensation are needed to make a long-term commitment.
- **Avoid real-time pressure**: Recruiters gain valuable insights over phone calls. To reduce information asymmetry, favor email, where you can be thoughtful and deliberate. Delay commitment by saying you’ll consider it or need to speak with someone.
- **Use neutral language**: Phrases like “That’s interesting” help you remain agreeable without showing your hand. Avoid affirming too positively during negotiations to preserve leverage.
- **Commit only at the end**: Only offer verbal commitments once the negotiation reaches final stages. At this point, you can say something like, “If you can meet $X in signing bonus or equity, I’ll sign tomorrow.” This gives the recruiter a clear target and a sense of closure.
- **Respect your word**: When making such final commitments, be sincere and only offer them if you’re truly ready to accept. This maintains credibility and professionalism.

Master The Behavioral Interview [Part 5] - It’s A Conversation

If you're doing it right, behavioral interviews shouldn't even feel like interviews. This lesson teaches you:

- Why behavioral interviews should feel like a conversation
- How the flow of behavior interviews are fundamentally different from all other interview types
- Why behavioral interviews are actually about far more than just the words you say
- The importance of honesty in interviews, not just in reality but with perception as well

Here is the communication course: [\[Course\] Effective Communication For Engineers](https://www.jointaro.com/course/effective-communication-for-engineers/)

DSA Crash Course [Part 23] - Linked List Warm Up Lecture

In this lecture, Alvin goes over how to implement a linked list in python.

If you need additional support taking these DSA skills and actually applying them, take [**Alvin's**](https://www.linkedin.com/in/alvin-zablan-b73a92117/) *complete* data structures and algorithms course on [**Structy**](https://structy.net/?utm_source=taro). You can try out the concepts yourself in their interactive code editor and learn advanced DSA patterns like stack exhaustive recursion.

Use [**this link to get 20% off**](https://structy.net/purchase?promo_code=taro20) the entire Structy DSA learning experience.

Follow Alvin on LinkedIn: <https://www.linkedin.com/in/alvin-zablan-b73a92117/>

Level Up Your Code Quality As A Software Engineer [Part 27] - Continue The Learning Journey

Watching one course is not going to automatically make you master of code quality (or anything really). To really learn these concepts and burn them into your mind, you need to continue the learning journey. What's next:

- If you have mastered code quality, then here's a great skill for you to move on to: [\[Masterclass\] How To Become A Debugging Master And Fix Issues Faster](https://www.jointaro.com/lesson/ioR6WzamAIUTpySLAr7o/masterclass-how-to-become-a-debugging-master-and-fix-issues-faster/)
- Apply your coding skills to open source! [Become An Open Source Master](https://www.jointaro.com/course/become-an-open-source-master/)

Truly Mastering A Data Structures And Algorithms Problem  - 2 Sum Example

Why is the following not a good way to remember the solution to 2 Sum?
        
def twoSum(self, nums, target):
    required = {}
    for i in range(len(nums)):
        if target - nums[i] in required:
            return [required[target - nums[i]],i]
        else:
            required[nums[i]] = i

Why is [Look for the difference and use a HashSet] a great way to remember the solution to 2 Sum?

What more general higher-level learning principle is also exercised alongside the proper mastery of data structures and algorithms problems?

Data structures and algorithms are a core part of FAANG software engineer interviews, and they're seemingly the bane of every software engineer's existence. However, so many software engineers don't learn these concepts properly.

Here are the core points from the video:
- In this example, we cover 2 sum, a classic data structures and algorithms problem that many companies use on phone screens. Here's how to learn it properly:
  - **Bad:** Memorizing all the code behind the optimal implementation.
  - **Good:** "Look for the difference and use a HashSet."
- All DSA problems will have this core insight that "unravels" the entire thing. Once you find and truly understand this insight, the implementation should flow naturally.
- This is also a sign of higher learning via "thinking in terms of abstractions". Your brain is a lot more powerful if it is able to take something more singular and high-level and convert it into the nitty gritty. Memorizing everything at the lowest level simply isn't scalable.

Related resources:
- [[Masterclass] How To Ace Your Big Tech Interview - Data Structures & Algorithms](https://www.jointaro.com/lesson/V4sTACzfOh22nMVcUV3w/how-to-ace-your-big-tech-interview-data-structures-and-algorithms-7172021/) - This is the full video this clip is taken from
- [[Masterclass] How To Ace Your Big Tech Interview - System Design](https://www.jointaro.com/lesson/J3I9fTW9ulr6T9KjxpqY/how-to-ace-your-big-tech-interview-system-design-1162021/)
- [How Alex Got Into Meta With 0 Prior Leetcode Experience](https://www.jointaro.com/lesson/ZYiTbN21FsqFxFdpwt5a/how-alex-got-into-meta-with-0-prior-leetcode-experience/)

Become A Debugging Master [Part 5] - Prioritization

Once you find a bunch of bugs, the next critical skill is knowing how to prioritize them. Here are the core points from the lesson:

- Use a framework of frequency vs. severity to quickly assess whether a bug is urgent, trivial, or somewhere in between
- For ambiguous cases, combine metrics (how many users impacted, company priorities) and your own judgment to make a strong recommendation
- Proactively get input from teammates with more context, and be prepared to justify why you’re working on a bug—or why it’s not worth fixing
- Developing this prioritization skill is key to advancing into senior and staff engineering roles, where you guide not just your own work but the team’s direction

[Case Study] Building XFN Alignment Across Multiple Orgs (w/ Staff Engineer Cat Chen)

[Cat Chen](https://catchen.me/) talked about his success building alignment across multiple orgs. 

Cat was working at Facebook as a Staff Engineer on the growth team. His charter to get the Android apps on app stores beyond the Play Store. (There were 10+ non-Google stores where Android apps get downloaded with some level of traffic.

Getting an app listed on a 3rd-party platform is simple – sign up as a developer on that platform; upload the Android app for review; wait for approval and launch it. Just as simple as publishing to Google Play.

**BUT it's not that simple at a company like Facebook.** Facebook lawyers wouldn’t allow Cat to accept the Terms of Service on behalf of Facebook the company. Cat didn’t have the privilege to bind Facebook into this contract and even if he did, the lawyers would certainly advise against that.

Instead of simply handing this problem to another person or org, Cat met with a director-level lawyer. Given he was on a different time zone, and in a different job function altogether, this took some legwork. The director explained the risk profile (Facebook could have unlimited downside by blindly accepting an agreement). Eventually Cat discovered a workable solution by using a contracting company to sign the legal agreement, which limits the damages that Facebook may face.

Impact of this work: 
- Successful launch of the existing Android apps
- Ability to launch other apps in the future
- Deep and positive relationship with the legal team, and Cat owned that relationship (which made him indispensable)
- **Almost zero lines of code written!**

[Connect with Cat](https://www.linkedin.com/in/catchen/)

For more resources on how to communicate, build alignment, and operate as a Staff Engineer:
- ["How do I sell the vision behind a large, org-level project?"](https://link.jointaro.com/NGCrB2ifkkpDaDe69)
- ["What's the Difference Between A Senior And Staff Engineer?"](https://link.jointaro.com/BEM2RAjPFe8Pv7826)
- [Guide to Effective Communication](https://link.jointaro.com/mP3WEd4zt5ecnupX6)

Tech Career Growth Videos

Our instructional videos provide software engineers with insights needed for career growth. Masterclasses go incredibly in-depth on a specific tech topic while case studies are real examples from established engineering leaders.