Meta System Design Interview (questions, process, prep)

Today we’re going to go over the Meta system design interview, with 37 recent Meta system design interview questions, plus sample answers to the top 3 most common. 

The information in this guide comes in part from an analysis of nearly 100 real system design interview reports collected from Meta software engineer, engineering manager, and technical program manager candidates. We also discuss briefly the different expectations for each role.

The first thing you’ll need to know: Meta interviewers like to base questions on Meta products, so research the main ones thoroughly beforehand.

Let’s get started.

1. What to expect at a Meta system design interview
2. Meta system design interview questions
3. How to prepare for Meta system design interviews

Click here to practice system design interviews 1-on-1 with a Meta ex-interviewer

1. What to expect in a Meta system design interview↑

Meta system design interviews are typically given to software engineer, engineering manager, research engineer, and technical program manager candidates at levels L4 and up.

Depending on your role and level, you can expect 1-3 system design interviews, each lasting 45 minutes, as part of your onsite interview. Meta E6 level candidates, for example, usually face 2 system design interviews.

• Concurrency (threads, deadlock, starvation, consistency, coherence)
• Caching
• Database partitioning, replication, sharding, CAP Theorem
• Networking (IPC, TCP/IP)
• Real-world performance (relative performance RAM, disk, your network, SSD), availability, and reliability (types of failures, failure units, how failures may manifest, mitigations, etc.)
• Data storage and data aggregation
• QPS capacity/machine estimation (back of the envelope estimates), byte size estimation

1.3 What Meta evaluates in a system design interview

The architectural depth you’re expected to cover in a system design interview varies depending on your target role and level. But essentially, all roles are expected to demonstrate the following traits in a system design interview:

• Clear understanding of the problem, including which parts of the problem are most critical, and identifying the requirements to design for
• Ability to identify dependencies and trade-offs and reason through them
• Knowledge of how to build and optimize at Meta’s scale
• Ability to communicate technical ideas and understand feedback

1.4 System design interviews for top roles (SWE, EM, TPM)

In this section, let's briefly differentiate the system design interview expectations for the top 3 roles that get this interview at Meta: software engineer, engineering manager, and technical program manager. Click here to skip straight to the questions.

Meta SWE

The system design interview for Meta SWEs evaluates your ability to design a solution to a complex problem, with an awareness of high-level goals, risks, and failure points.

Some of the areas Meta wants you to address include a system’s testability, usability, extensibility, security, portability, availability, and scalability. They also want to see how you diagnose or debug a problem that might occur with the system.

Interview expectations vary depending on your level. Here’s a quick summary of what you’re expected to cover based on your level, according to Marvin (ex-Amazon, Reddit senior SWE) and Tarek (ex-Amazon EM):

• L4 SWE: Focus will be on foundational reasoning, clarity in communication, structured thinking, and basic understanding of key components (e.g., databases, caches, queues). 
• L5 SWE: Expect to go deeper into scaling, data flow, and basic fault tolerance. Interviewers will be looking for thoughtful simplification and an awareness of real-world constraints.
• L6-L7 SWE: You need to demonstrate ownership of the entire design process, depth in trade-offs, scalability, data modeling, and operational concerns. You'll need to lead the conversation.

Click here to learn more about the entire software engineer interview process at Meta.

Meta EMs

The Meta EM system design interview is focused on evaluating how you lead the building of a Meta-scale system. You're expected to call out the challenges and opportunities that come with building such a solution, and how the solution will perform given the possible bottlenecks and limitations.

As an EM candidate, you won’t be expected to get into the low-level design of a system, but you’ll still need to demonstrate that you can if needed. You’ll instead focus on the high-level architecture, outlining major system components and data flows.

The best way to differentiate yourself as an EM, according to Mathew (ex-AWS SDM), is to proactively weigh trade-offs in scalability, performance, cost, and complexity. You also want to acknowledge the inevitability of technical debt and what you plan to do about it. And finally, you need your design choices to allow for adjustments and major changes like scaling, upgrades, and migrations.

Click here to learn more about the Meta engineering manager interview process.

Meta TPMs

The Meta TPM system design is focused on evaluating your structured, methodical approach to problem-solving and technical program management, including how you’ll devise a technical strategy to hit all your goals while calling out technical trade-offs. Your goal is to show that you'll be able to collaborate closely with engineers with a good understanding of design decisions.

When discussing technical design, you won’t be expected to go low level. Focus instead on traffic and data flow. Have a strategy for achieving technical goals, and if interviewing at a managerial level, communicate the business impact of architectural decisions.

Click here to learn more about the Meta TPM interview process.

2. Meta system design interview questions↑

Now you have an idea of how system design interviews work at Meta, let’s get into the complete list of system design questions that have been asked in real Meta interviews, according to data from Glassdoor.

Out of all the Meta system design interview questions that we collected from Glassdoor, these first three questions were repeated multiple times across different roles. We've laid out an answer outline for each.

Below each question, you’ll find a repeatable framework that you can use to answer any system design interview question. For a full explanation of the framework, consult our system design question guide. 

2.1 Design Instagram

From what we've seen, this is probably the most common system design interview question at Meta.

“Design Instagram” requires candidates to tackle an incredibly complex task— building a social media app— in 45 minutes.

Below, take a look at some points of consideration and questions to keep in mind when tackling this problem.

Watch ex-Meta data engineer Karthik work through this system design challenge below:

2.2 Design X part of Facebook

Varying versions of this question came up frequently in the interview reports from Meta, asking candidates to design a particular feature of Facebook or design a made-up feature.

The most common was 'Design the Facebook Newsfeed' (now called just "Feed") so let's take a look at how you could approach it.

For a more detailed look at the problem, check out this written answer to "Design a news feed" from ByteByteGo

2.3 Design a messaging app

This is another common question in system design interviews at Meta, as it is at other FAANG companies. You might be asked to design a generic messaging app, WhatsApp, or Facebook Messenger. Let's take a look at a way of approaching it.

Come up with your own solution to "design a messaging app" then watch the video below to see how an ex-Google engineering manager does it.

3. More Meta system design interview questions

Now, let’s get into the complete list of system design interview questions asked in interviews for different roles at Meta.

Keep in mind that, in most cases, your interviewer will adapt the question to your background. For instance, if you've worked on an API product, they're more likely to ask you to design an API. But that won't always be the case, so practice with the questions below to be ready to design any type of product or system at a high level.

We’ve divided the questions by role: software engineer, engineering manager, and technical program manager. 

As we've discussed in Section 1, interviewers use system design prompts to test for different skills depending on your role. For example, engineering managers will be expected to give more in-depth answers than software engineers, including a discussion of how the system would play into the larger business context of the company. TPMs must be able to discuss the merits of different architectures in order to work with engineers.

Test out your skills using the questions below.

You can also check out the following guides for additional tips and practice questions:

• System design interview questions guide, where you’ll find more insights, example questions, and answer outlines from FAANG experts
• Machine learning system design interview or generative AI system design interview guides, if you're applying for an AI/ML engineering role. 
• System design interview questions for product managers, if you're applying to PM-T roles
• System design interview questions for data engineers, if you're applying to data engineering roles
• Staff system design interview questions guide, if you're applying for a staff-level engineering role

4. How to prepare for Meta system design interviews

Now that you know what questions to expect, let’s focus on preparation. Below are links to free resources and four steps to help you prepare for your Meta system design interviews.

4.1 Learn the interview process

Of course, your system design interviews at Meta will be part of a larger interview process. For help understanding the overall interview process and practice questions for every type of question you’ll be asked, use one of the guides below.

• Meta software engineer interview guide
• Meta engineering manager interview guide
• Meta technical program manager interview guide
• Meta research engineer interview guide

If you're applying for engineering roles, you'll also want to prepare for coding interviews. Check out our guide to Meta coding interviews to learn more.

Now, let’s dig deeper into system design interview prep.

4.2 Learn the concepts

There is a base level of knowledge required to be able to speak intelligently about system design. You don't need to know EVERYTHING about sharding, load balancing, queues, etc. 

However, you will need to understand the high-level function of typical system components. You'll also want to know how these components relate to each other, and any relevant industry standards or major tradeoffs. 

To help you get the foundational knowledge you need, we've put together a series of 9 system design concept guides. Here's the full list:

1. Network protocols and proxies, which make it possible for any networked computers to talk to each other, no matter where they are or what hardware or software they’re running.
2. Databases, integral components of the world’s biggest technology systems.
3. Latency, throughput, and availability, three common metrics for measuring system performance.
4. Load balancing, the process of distributing tasks over a set of computing nodes to improve the performance and reliability of the system.
5. Leader election algorithms, which describe how a cluster of nodes without a leader can communicate with each other to choose exactly one of themselves to become the leader. 
6. Caching, a technique that stores copies of frequently used application data in a layer of smaller, faster memory in order to compute costs and to improve data retrieval times and throughput.
7. Sharding, the horizontal scaling of a database system that is accomplished by breaking the database up into smaller “shards,” which are separate database servers that all contain a subset of the overall dataset.
8. Polling, SSE, and WebSockets, techniques for streaming high volumes of data to or from a server.
9. Queues and pub-sub, mechanisms that allow a system to process messages asynchronously, which can eliminate bottlenecks and help the system to operate more efficiently.

We’d encourage you to begin by studying these topics, and once you understand the basics, you can begin practicing system design questions.

4.3 Practice with a repeatable answer framework

We recommend using a repeatable answer framework when answering system design interview questions. You can learn more about that framework in our system design interview guide, but in the meantime, here is a summary:

Step 1: Ask clarifying questions

First, spend about five minutes checking in with your interviewer about the functional and non-functional requirements of what you’re going to design. Ask about the system’s goals and how they will be measured. Be sure that you fully understand the question before moving forward.

Call out any assumptions you’re making that will influence your design approach. If applicable, ask about non-functional requirements such as availability, consistency, scalability, etc.

Step 2: Design high-level

Start the high-level design by specifying one to two metrics (e.g. number of users added, products sold before vs after a feature launch, etc.). Then use these metrics to do some simple calculations in order to find the optimal usage pool of the system.

Once you’ve defined your metrics, map out only the most functional components of the system (e.g., front end, web server, database, etc.).

Finally, before getting into the more detailed aspects of your system, make some decisions on how you will design its database. Choose whether it will be a relational or a NoSQL database, as well as its metadata and table structure.

Step 3: Drill down on your design

If you haven’t already, start mapping out the system on your whiteboard. Speak through your diagram so that your interviewer can follow along and ask questions when necessary.

Consider any bottlenecks that may arise when it comes to the system’s scalability, performance, or flexibility.

To finalize your design, play to your strengths by choosing a component you’re more familiar with and drilling down on it. If you’re not sure which component would be best to explore, ask your interviewer.

Step 4: Bring it all together

Before wrapping up the round, take about five minutes to re-examine what you’ve designed. Does it meet the objectives you laid out with the interviewer at the beginning of the session? It is okay to change some components at this stage if you think it will improve the system, but you must explain to the interviewer what you are doing and why.

Apply this framework to practice questions like those we’ve provided above. Use it on different types of questions in a variety of subjects, so that you learn how to adapt it to different situations and respond to unpredictable questions on the fly.

4.4 Practice with peers

Once you've done some individual practice, we would also strongly recommend that you practice solving system design questions with someone else interviewing you.

If you have friends or peers who can do mock interviews with you, that's an option worth trying. It’s free, but be warned, you may come up against the following problems:

• It’s hard to know if the feedback you get is accurate
• They’re unlikely to have insider knowledge of interviews at your target company
• On peer platforms, people often waste your time by not showing up

For those reasons, many candidates skip peer mock interviews and go straight to mock interviews with an expert. 

4.5. Practice with experienced system design interviewers

In our experience, practicing real interviews with experts who can give you company-specific feedback makes a huge difference.

Find a Meta system design interview coach so you can:

• Test yourself under real interview conditions
• Get accurate feedback from a real expert
• Build your confidence
• Get company-specific insights
• Save time by focusing your preparation

Landing a job at a big tech company often results in a $50,000 per year or more increase in total compensation. In our experience, three or four coaching sessions worth ~$500 make a significant difference in your ability to land the job. That’s an ROI of 100x!