Landing a job at Facebook is a dream for many developers around the globe. Facebook is one of the top tech companies in the world, with a workforce of over 52,000 strong. A company culture based on growth, fast promotion paths, great benefits, and top salaries are just a few of the things that Facebook is known for.
But there is a lot of competition, and Facebook is looking for the best candidates because they have hired a lot of new people. Facebook focuses on your cultural fit, generalist knowledge, ability to build within constraints, and expert coding skills.
It’s time to get ready for your Facebook interview! Today I’ll go over everything you need, including coding questions and a step-by-step guide to getting ready.
To land a software engineering job at Facebook, you need to know what lies ahead. The more prepared you are, the more confident you will be. So, let’s break it down.
As a developer looking to work with Facebook’s platform, you can expect to face some tough technical interview questions about the Facebook Graph API. Mastering this powerful tool for accessing Facebook data will be key for succeeding in these job interviews.
In this comprehensive guide, I’ll provide an overview of some of the most common and advanced Facebook Graph API interview questions you’re likely to encounter. Whether you’re an experienced developer or just starting out, understanding these key Graph API concepts is essential preparation for landing your dream job.
Overview of the Facebook Graph API
First, what exactly is the Facebook Graph API? In simple terms, it’s the primary way for apps to read and write data to Facebook It exposes objects in Facebook (like users, photos, pages etc) and the connections between them (like friend relationships, shared content etc).
The Graph API represents this Facebook data as a social graph, with nodes and edges. This provides a uniform representation of the objects in Facebook’s social graph and how they relate to each other.
Now let’s dive into some sample Facebook Graph API interview questions:
Common Facebook Graph API Interview Questions
Q1: How does authentication work with the Graph API?
To authenticate a user, you need to implement OAuth 2.0. The user clicks a Login with Facebook button, which redirects them to Facebook’s login flow. After entering credentials, Facebook sends back an authorization code which your app exchanges for an access token. The token grants temporary permission to access that user’s data.
Q2: Explain how you can post to a user’s timeline using the Graph API.
Use the /{user-id}/feed endpoint with the publish_actions permission and HTTP POST method. The request body should contain a message parameter with the content to post. The access token must belong to that user or have the manage_pages permission if posting as a page.
Q3: How does pagination work when accessing lists of data from the Graph API?
The Graph API uses cursors for pagination. The paging field in responses contains before and after cursors to navigate data sets. Pass the after cursor as a parameter to get the next page, before to go back a page. This is more reliable than using offsets.
Q4: What are some common errors when using the Graph API and how can you handle them?
Errors like 400 Bad Request or 500 Internal Server Error. Set up error handling code to catch exceptions from the Graph API SDK. Inspect the error response for details like the error type, message, and troubleshooting tips. Gracefully handle errors by showing custom messages to users.
Q5: How can you get optimized performance when using the Graph API?
Techniques like enabling batch requests to reduce round trips, liberal use of caching, persisting data locally, requesting only needed fields, and parallelizing independent requests can improve performance. Use tools like the Graph API Explorer to analyze queries.
Advanced Facebook Graph API Interview Questions
Now let’s look at some more complex and in-depth questions:
Q1: Describe how you would request multiple data resources in a single call using the Graph API?
Use the Batch Requests API which allows up to 50 operations in one call. This reduces round trips while keeping requests atomic. Specify each individual request in the batch array parameter. The responses will be returned in a single JSON array matching the order.
Q2: How can you implement paging in results from the Graph API in an optimized way?
Use cursors over offsets for paging as they are more performant. Initially fetch pages in smaller chunks like 25 results. Analyze time taken and increase page size gradually ensuring times stay within limits. Pre-fetch next pages asynchronously while user views current page.
Q3: What are some best practices for handling errors when using the Graph API?
Set up custom exception handling with classes for each error type. Log errors with context like request parameters. Gracefully degrade functionality if parts of API fail. Exponential backoff retries for recoverable errors. Alert monitoring for spikes in errors. Provide friendly user messages.
Q4: How would you minimize API call latency when using the Graph API?
Enable local caching of responses on disk or in memory using cache expiration. Scale out API servers across regions closer to users. Parallelize independent requests. Reduce payload sizes by filtering fields and compression. Use HTTP persistent connections. Optimally batch compatible operations. Prefetch data in advance.
Q5: What are some ways to optimize bandwidth usage when using the Graph API?
Enabling GZip compression of requests and responses. Setting conditional requests to not re-download unchanged data. Caching responses locally and headers like ETag for cache validation. Removing unnecessary metadata from requests and responses. Downsampling images to optimal sizes. Paginating and limiting request size.
Key Takeaways
This covers a wide range of key Facebook Graph API concepts you could be quizzed on during your tech interview. I hope these example questions have provided a useful illustration of what to expect and how to demonstrate your expertise with this vital tool for integrating with Facebook’s platform.
Be sure to read Facebook’s Graph API documentation thoroughly and practice constructing sample requests and error handling flows. Experienced interviewers may probe your knowledge further with follow-up questions or hypothetical scenarios. Show them your ability to make intelligent design choices and identify potential pitfalls.
With diligent preparation using resources like this, you’ll be equipped to impress your interviewers and unlock exciting new career opportunities leveraging the power of the Facebook Graph API. Best of luck!
Backtracking: Find all possible subsets
We are given a list of integers and need to decide what other lists can be made out of them.
Runtime complexity: Exponential, O(2n∗n)O(2^{n} * n)O(2n∗n), where nnn is the number of integers in the given set
Memory Complexity: Constant, O(2n∗n)O(2^{n} * n)O(2n∗n)
There are several ways to solve this problem. We will discuss the one that is neat and easier to understand. We know that for a set of ‘n’ elements there are 2n2^{n}2n subsets. For example, a set with 3 elements will have 8 subsets. Here is the algorithm we will use:
It doesn’t matter what order the bits are in when you pick integers from the set; picking integers from left to right or right to left would give you the same result.
Arrays: Merge overlapping intervals
You are given a list (array) of interval pairs. Each interval has a timestamp for both the beginning and end. The input array is sorted by starting timestamps. You are required to merge overlapping intervals and return a new output array.
Consider the input array below. Ranges (1, 5), (3, 7), (4, 6), and (6, 8) overlap, so they should be combined into one big range (1, 8). Similarly, intervals (10, 12) and (12, 15) are also overlapping and should be merged to (10, 15).
Try it yourself before reviewing the solution and explanation.
Runtime complexity: Linear, O(n)O(n)O(n)
Memory Complexity: Linear, O(n)O(n)O(n)
This problem can be solved in a simple linear scan algorithm. We know that input is sorted by starting timestamps. Here is the approach we are following:
- We are given a list of intervals to work with, and we will keep the merged intervals in the output list.
- For each interval in the input list:
- The input interval and the last interval in the output list will be merged if they overlap. The last interval in the output list will then be updated with the merged interval.
- Otherwise, we’ll add an input interval to the output list.
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FAQ
What is Facebook Graph API used for?
How do you read someone’s Facebook message using Graph API?
What is the limit of Facebook Graph API posts?
How to read and write data on Facebook social graph?
Let’s first start with the Graph API. Graph API is the primary way to access means read and write data on the social media Facebook social graph. We will first discuss the overview of the Graph API, proceeding to the setup, we will then finally see how to use Graph API Explorer for reading and writing data on Facebook Social Graph.
What questions are asked in a Facebook interview?
Coding Questions: Facebook interview questions focus on generalist knowledge on algorithms, data structures, and time complexity. They also test on architecture and system design (even entry level). Hiring Levels: Facebook normally hires at level E3 for entry level software roles with E9 behind the height of levels.
How long is a Facebook interview?
Types of Interviews: The interview process consists of 6 to 7 interviews. This includes 1 pre-screen interview (20 minutes), 1 technical phone interview (50 minutes, 1-2 coding questions), and 4-5 on-site interviews (45 minutes each). On-site interviews: Facebook breaks the on-site interviews into three sections.
Does Facebook have a coding interview?
Like many other top tech companies, Facebook sets a high bar for technical talent, and their interview process reflects this. Cracking the Facebook coding interview is any developer’s dream. Today, we’ll walk through the ins and outs of the Facebook interview with 40 coding interview questions.
