Meta E4 Interview Questions: 30 Real Questions with Solutions (2026)

Meta's E4 (Software Engineer) interview is a fast-paced, high-volume process that tests coding speed, system design thinking, and behavioral fit. This guide breaks down every round, 30 real questions with solutions, and a minute-by-minute walkthrough to help you prepare strategically.

The Meta E4 Interview Process

A standard Meta E4 loop:

1. Recruiter screen (15–30 min) — Background, role fit, salary expectations
2. Technical phone screen (45–60 min) — 1–2 coding problems
3. Virtual on-site — 4–5 rounds:
   • 2 coding rounds (2 problems each, medium difficulty, 35–40 min per round)
   • 1 system design round (45 min)
   • 1 behavioral round (45 min)
   • 1 optional behavioral/role-specific round (depending on team)

Meta's coding rounds are different from Google — they focus on two problems per round with strict time limits. You need to solve both problems in 35–40 minutes, which means speed matters more than depth.

Meta E4 Interview Process Flowchart

flowchart TD
    A["Recruiter Screen"] --> B["Phone Screen - 45-60 min"]
    B --> C{"Pass?"}
    C -->|"No"| D["Reapply in 6-12 months"]
    C -->|"Yes"| E["Virtual On-site Loop"]
    E --> F["Coding Round 1 - 2 problems, 40 min"]
    F --> G["Coding Round 2 - 2 problems, 40 min"]
    G --> H["System Design Round - 45 min"]
    H --> I["Behavioral Round - 45 min"]
    I --> J["Hiring Committee Review"]
    J --> K{"Decision?"}
    K -->|"Strong Hire"| L["Offer"]
    K -->|"Lean Hire"| M["Team Matching"]
    K -->|"No Hire"| D

Screening Round

Format: 1–2 coding problems, 45–60 minutes

Typical Questions:

1. Merge Intervals — Given an array of intervals, merge all overlapping intervals. Time: O(n log n).
2. Valid Palindrome II — Check if a string is a palindrome, allowing at most one deletion. Time: O(n).

Difficulty: Medium. Meta uses screening to filter out candidates who can't code clean solutions under time pressure.

Tip: Meta interviewers care about speed and correctness. Solve the first problem in 15 minutes, leave room for the second.

Coding Rounds

Format: 2 problems per round, 35–40 minutes each (2 rounds total)

Meta's coding rounds are fast, not deep. You'll face two medium-difficulty problems per round and be expected to:

• Solve both problems within the time limit
• Write clean, bug-free code
• Handle edge cases
• Optimize when asked

Round 1 — Typical Problem Types

• Arrays and strings (two pointers, sliding window)
• Hash maps and sets
• Binary trees (BFS/DFS, level-order)

Round 2 — Typical Problem Types

• Graph algorithms (BFS/DFS, shortest path)
• Dynamic programming (1D, 2D)
• Stack and queue problems

Tip: Meta interviewers will interrupt if you're going down the wrong path. Listen to their hints — they're trying to help you solve it faster.

System Design Round

Format: 1 system design problem, 45 minutes

Common E4 Questions:

1. Design Instagram (feed, stories, explore)
2. Design Facebook Messenger (chat, groups, calls)
3. Design a URL shortener (like fb.ly)
4. Design a news feed system (ranking, delivery)
5. Design a notification system (push, email, SMS)

What Meta Evaluates at E4:

• Can you define requirements and scale?
• Can you design a high-level architecture?
• Can you handle 1B+ users?
• Do you understand caching, replication, and partitioning?
• Can you dive deep into specific components?

Tip: At E4, Meta expects you to lead the discussion. Present your design, ask for feedback, and iterate. Don't get stuck on one component — show breadth.

Behavioral Round

Format: Behavioral interview, 45 minutes

Meta's behavioral round evaluates:

• Leadership — Have you led projects? Made decisions with impact?
• Collaboration — Do you work well with others? Handle disagreements?
• Growth — Do you learn from failures? Improve processes?

Common Questions:

1. Tell me about a time you led a project without formal authority
2. Describe a situation where you had to make a decision with incomplete information
3. How do you handle disagreements with teammates?
4. Tell me about a time you failed and what you learned
5. Describe a project where you improved a process or system significantly
6. How do you prioritize when everything seems urgent?

Tip: Use STAR format (Situation, Task, Action, Result). Quantify impact. Meta values "move fast" — show you can ship quickly without breaking things.

30 Real Meta E4 Questions

Arrays & Strings

Q1. Two Sum — Given an array of integers and a target, return indices of two numbers that add up to the target.

Solution: Use a hash map to store seen numbers. For each number, check if target - num exists in the map. Time: O(n), Space: O(n).

Q2. Container With Most Water — Find two lines that together with the x-axis form a container holding the most water.

Solution: Two pointers from both ends. Move the pointer pointing to the shorter line inward. Time: O(n).

Q3. Product of Array Except Self — Return an array where each element is the product of all other elements without using division.

Solution: Compute prefix products and suffix products in two passes. Time: O(n), Space: O(1) extra.

Q4. Longest Substring Without Repeating Characters — Find the length of the longest substring without repeating characters.

Solution: Sliding window with a hash set. Expand right, contract left when duplicate found. Time: O(n).

Q5. Minimum Window Substring — Find the minimum window in string s that contains all characters of string t.

Solution: Sliding window with character frequency map. Expand until all characters covered, then contract from left. Time: O(n).

Q6. Group Anagrams — Group strings that are anagrams of each other.

Solution: Use sorted string as key in hash map. Group all strings with the same sorted key. Time: O(n * k log k).

Trees & Graphs

Q7. Validate Binary Search Tree — Check if a binary tree is a valid BST.

Solution: In-order traversal with range checking. Pass min/max bounds down the tree. Time: O(n).

Q8. Lowest Common Ancestor of a Binary Tree — Find the LCA of two nodes in a binary tree.

Solution: Recursive DFS. If current node is null or matches either target, return it. Recurse left and right. If both return non-null, current is LCA. Time: O(n).

Q9. Serialize and Deserialize Binary Tree — Design an algorithm to serialize and deserialize a binary tree.

Solution: Pre-order traversal with null markers. Deserialize by reading values sequentially and rebuilding the tree. Time: O(n).

Q10. Number of Islands — Given a 2D grid, count the number of islands (connected 1s surrounded by 0s).

Solution: BFS/DFS from each unvisited 1, marking all connected 1s as visited. Time: O(m * n).

Q11. Binary Tree Right Side View — Return the values of the nodes you can see from the right side of the tree.

Solution: BFS level-order traversal, take the last node at each level. Time: O(n).

Q12. Graph Valid Tree — Given n nodes and edges, determine if the graph is a valid tree.

Solution: Check two conditions: (1) exactly n-1 edges, (2) graph is connected via BFS/DFS. Time: O(n).

Dynamic Programming

Q13. Climbing Stairs — You can climb 1 or 2 steps. How many distinct ways to reach the top?

Solution: Classic Fibonacci. dp[i] = dp[i-1] + dp[i-2]. Time: O(n), Space: O(1).

Q14. Longest Increasing Subsequence — Find the length of the longest strictly increasing subsequence.

Solution: DP with binary search. Maintain a tails array where tails[i] is the smallest tail of all increasing subsequences of length i+1. Time: O(n log n).

Q15. Word Break — Given a string and a dictionary, determine if the string can be segmented into dictionary words.

Solution: DP. dp[i] = true if s[0..i] can be segmented. Check all possible splits. Time: O(n^2 * m) where m is average word length.

Q16. Coin Change — Find the fewest coins needed to make up an amount.

Solution: Bottom-up DP. For each amount from 1 to target, try each coin and take the minimum. Time: O(amount * coins).

Q17. Maximum Subarray — Find the contiguous subarray with the largest sum.

Solution: Kadane's algorithm. Track current sum, reset to 0 when it goes negative. Time: O(n).

Q18. House Robber — Rob houses without robbing two adjacent ones. Maximize total money.

Solution: DP. dp[i] = max(dp[i-1], dp[i-2] + nums[i]). Time: O(n), Space: O(1).

Stack & Queue

Q19. Valid Parentheses — Check if a string of brackets is valid.

Solution: Stack. Push opening brackets, pop on closing. Check match. Time: O(n).

Q20. Daily Temperatures — For each day, find how many days until a warmer temperature.

Solution: Monotonic stack. Push indices, pop when current is warmer. Time: O(n).

Q21. Min Stack — Design a stack that supports push, pop, top, and getMin in O(1).

Solution: Use two stacks — main stack and min stack. Push to min stack if value <= current min. Time: O(1) per operation.

Q22. Evaluate Reverse Polish Notation — Evaluate arithmetic expression in reverse Polish notation.

Solution: Stack. Push numbers, pop two on operator, push result. Time: O(n).

Hash Map & Design

Q23. LRU Cache — Design a data structure that follows LRU eviction policy.

Solution: Hash map + doubly linked list. Map for O(1) lookup, linked list for O(1) eviction. Time: O(1) per operation.

Q24. Two Sum — Given an array and target, return indices of two numbers that add up to target.

Solution: Hash map. For each num, check if target - num exists. Time: O(n).

Q25. Top K Frequent Elements — Find the k most frequent elements.

Solution: Hash map for frequency count, then min-heap of size k. Time: O(n log k).

Sliding Window

Q26. Longest Repeating Character Replacement — Find the longest substring with at most k character replacements.

Solution: Sliding window. Track max frequency in window. Expand right, contract left when window size - max frequency > k. Time: O(n).

Q27. Permutation in String — Check if s2 contains a permutation of s1.

Solution: Sliding window of size s1.length. Track character counts. Time: O(n).

Binary Search

Q28. Search in Rotated Sorted Array — Search for a target in a rotated sorted array.

Solution: Modified binary search. Determine which half is sorted, then decide where to search. Time: O(log n).

Q29. Find Minimum in Rotated Sorted Array — Find the minimum element in a rotated sorted array.

Solution: Binary search. Compare mid with right. If mid > right, min is in right half. Time: O(log n).

Q30. Koko Eating Bananas — Find the minimum eating speed to finish all bananas within h hours.

Solution: Binary search on answer space [1, max(piles)]. Check if speed k finishes in h hours. Time: O(n * log(max(piles)).

Minute-by-Minute Walkthrough

Coding Round 1 (40 minutes)

Coding Round 2 (40 minutes)

System Design Round (45 minutes)

Behavioral Round (45 minutes)

How to Prepare

8-Week Study Plan

Key Differences from Other Companies

Frequently Asked Questions

How long does the Meta E4 interview process take?

The entire process, from recruiter screen to offer, typically takes 4–8 weeks. The on-site itself is usually completed in one day (virtual) or two days (onsite).

What is the acceptance rate for Meta E4?

Meta's overall acceptance rate is estimated at 2–5%. For E4 specifically, it's slightly higher because the bar is lower than E5/E6, but still competitive.

How many problems do I need to solve per coding round?

You need to solve both problems in each coding round. Solving only one significantly reduces your chances of passing.

Is system design required for E4?

Yes, system design is part of the E4 loop. At E4, Meta expects you to design a complete system, not just components.

What happens if I fail one round?

Meta evaluates the entire loop holistically. Failing one coding round doesn't automatically disqualify you, but it significantly hurts your chances. Strong performance in other rounds can compensate.

How should I prepare for Meta's behavioral round?

Prepare 6–8 STAR stories covering leadership, conflict, failure, and impact. Meta values "move fast" — show you can ship quickly without breaking things.

Put It Into Practice

Reading about questions is different from solving them under pressure. InterviewSkool runs a real FAANG-style mock interview with AI interviewer Alex, then gives you a hiring signal and detailed feedback.

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