Twilio coding interview
questions, leaked.
13 problems reported across recent Twilio interviews. Top patterns: array, string, greedy. The list below is what most reported candidates actually saw, plus the honest play if you can't grind all of it.
Twilio's online assessment is 13 problems. You'll face 2 easy, 7 medium, and 4 hard. Most of that is arrays and strings, which is good news if you've drilled fundamentals. The trap is greedy and hash-table problems mixed into the medium tier. If you blank mid-OA on a hash-table or sorting hybrid, StealthCoder runs invisibly during screen share and surfaces a working solution in seconds. You won't have time to re-drill everything. Prep the patterns that appear most, then bank on the safety net for what you miss.
Top problems at Twilio
| # | Problem | Diff | Frequency | Pass % | Patterns |
|---|---|---|---|---|---|
| 01 | Maximize Greatness of an Array | MEDIUM | 100.0 | 59% | Array · Two Pointers · Greedy |
| 02 | Univalued Binary Tree | EASY | 93.3 | 72% | Tree · Depth-First Search · Breadth-First Search |
| 03 | Reformat Date | EASY | 91.3 | 67% | String |
| 04 | Letter Combinations of a Phone Number | MEDIUM | 65.4 | 64% | Hash Table · String · Backtracking |
| 05 | Top K Frequent Elements | MEDIUM | 65.4 | 65% | Array · Hash Table · Divide and Conquer |
| 06 | Text Justification | HARD | 56.8 | 48% | Array · String · Simulation |
| 07 | Minimum Number of Swaps to Make the String Balanced | MEDIUM | 56.8 | 78% | Two Pointers · String · Stack |
| 08 | Minimum Equal Sum of Two Arrays After Replacing Zeros | MEDIUM | 56.8 | 50% | Array · Greedy |
| 09 | Group Anagrams | MEDIUM | 56.8 | 71% | Array · Hash Table · String |
| 10 | First Missing Positive | HARD | 56.8 | 41% | Array · Hash Table |
| 11 | Reconstruct Itinerary | HARD | 56.8 | 44% | Depth-First Search · Graph · Eulerian Circuit |
| 12 | Wildcard Matching | HARD | 56.8 | 30% | String · Dynamic Programming · Greedy |
| 13 | Ways to Make a Fair Array | MEDIUM | 56.8 | 64% | Array · Prefix Sum |
Frequencies derived from public community-tagged interview reports. Click a row to view on LeetCode.
You have a week, maybe less. You can't out-grind the list above. StealthCoder runs invisibly during the actual Twilio OA. The proctor cannot see it. Screen share cannot detect it. Built because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround.
Get StealthCoder- array7 · 54%
- string6 · 46%
- greedy4 · 31%
- hash table4 · 31%
- sorting3 · 23%
- two pointers2 · 15%
- depth first search2 · 15%
- backtracking1 · 8%
- tree1 · 8%
- breadth first search1 · 8%
Arrays dominate the assessment (7 problems), so your first week is array manipulation, sorting, and prefix-sum logic. Strings come next (6 problems), often paired with arrays or hash tables. Greedy and hash-table problems (4 each) are where medium climbs to hard. Sorting, two-pointers, and DFS each appear 2 to 3 times. The topography is clear: master array transformation and string parsing before you touch backtracking or tree traversal. Three of the hardest problems (Reconstruct Itinerary, Wildcard Matching, First Missing Positive) use patterns that don't repeat, so you can't brute-force memorization. This is where StealthCoder is the hedge. You drill the 70 percent that repeats. When you hit the outlier hard problem live, you have a real-time solution.
Companies with similar patterns
If you prepped for Twilio, these companies recycle ~60% of the same topics.
You've seen the list.
Now make sure you pass Twilio.
Memorizing every problem above in a week is a fantasy. StealthCoder is the hedge: an AI overlay that's invisible during screen share. It reads the problem on screen and surfaces a working solution in under 2 seconds. Built because the OA filter rejects engineers who'd pass the on-site. That's a broken filter. This is the workaround. Works on HackerRank, CodeSignal, CoderPad, and Karat.
Twilio interview FAQ
Should I focus on arrays first for Twilio?+
Yes. Seven of the 13 problems involve arrays, and most mediums use arrays with greedy or two-pointer logic. Spend your first pass on array manipulation, sorting, and prefix-sum patterns. You'll recognize at least half the assessment immediately.
How much time should I spend on hash-table problems?+
Hash-table appears in 4 problems, often paired with strings or arrays. It's not the primary focus, but it's the gate between easy and medium. Spend 2 to 3 days on hash-table basics (Top K Frequent Elements, Group Anagrams) before you tackle harder combinations.
Are greedy problems common enough to drill heavily?+
Greedy shows up 4 times, often in medium problems like Maximize Greatness and Minimum Number of Swaps. It's frequent enough to prioritize, but the patterns differ per problem. Drill the two or three Twilio greedy problems directly, then use live problem-solving for variations.
What about the hard problems like Wildcard Matching and Reconstruct Itinerary?+
Those four hard problems use distinct patterns (dynamic programming, graph traversal, string recursion). They won't repeat in the assessment. Understand one or two if time allows, but they're lower ROI. Focus on the 7 mediums, which share reusable logic.
How much string practice is needed?+
Strings appear in 6 problems and often mix with arrays or hash tables. Dedicate a few days to string parsing and transformation (Reformat Date, Group Anagrams), especially the simulation and greedy string problems. Text Justification is harder but teaches formatting discipline.