Tesla technical phone screen interview

Questions Tesla asks in this round 25

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  Keep a shared payment account correct under concurrent paymentsSystem designTwo people share one online payment account and pay with it at the same moment. How do you make sure the balance never goes wrong? Answer from the API side (idempotency, request…

  Possibly retiredWere you asked this too?
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  Key-value store with nested transaction rollbackCodingImplement an in-memory key-value store whose string keys map to string values. It supports transactions, and transactions can be nested. Implement the class KeyValueStore: -…

  Last asked Apr 2026Were you asked this too?
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  2D convolution forward pass in NumPy, with parameter countsCoding1. Given the input tensor shape, input channels, output channels, kernel size, stride and padding, how many parameters does a Conv2D layer have, with and without bias? What is the…

  Last asked Dec 2025Were you asked this too?
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  Trapping rain waterCodingGiven bar heights in an elevation map, each of width 1, compute how much water is trapped after rain. Start with the brute-force solution and its complexity, then improve it to…

  Possibly retiredWere you asked this too?
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  Design a Supercharger backend: billing, stall telemetry and finding a free chargerSystem designDesign the backend for a network of EV fast-charging sites, each with several stalls. Three requirements: 1. Billing: measure the energy delivered in every charging session and…

  Last asked Sep 2026Were you asked this too?
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  Implement reduce, then map and filter on top of itCodingIn any language, implement reduce yourself, then implement map and filter using only your reduce. Then use the three functions to process a small table of records the interviewer…

  Last asked Sep 2026Were you asked this too?
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  Call a flaky HTTP API with Python requests and handle every errorCodingUsing Python's requests, write a client for a few endpoints of a fake API (you have its docs; the code does not need to run against a real server). Handle the failure cases…

  Last asked Sep 2026Were you asked this too?
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  Design a content delivery networkSystem designDesign a CDN that serves static content from servers close to users. Cover how a request reaches the nearest edge, what the edge caches and for how long, cache misses and the path…

  Last asked Sep 2026Were you asked this too?
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  JSON merge API with pluggable merge behaviorsCodingDesign and implement a function that merges two JSON documents, where the way conflicts are resolved is pluggable: for example, how two objects, two arrays or two different scalar…

  Last asked Aug 2026Were you asked this too?
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  ML fundamentals deep dive for ML rolesML designAfter a short walk through your resume, expect fast questions on machine learning basics, usually centred on your own area (language models, vision, recommendations). For each…

  Last asked Jun 2026Were you asked this too?
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  Clean a CSV of transactionsCodingWrite a small pipeline that reads a CSV file of transactions, validates and normalizes each row (types, formats, missing values), decides what to do with rows that cannot be…

  Last asked May 2026Were you asked this too?
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  Design a ticket booking systemSystem designSell seats for concerts and games where demand spikes the moment sales open: hold seats briefly, never sell one twice, and stay up under the rush.

  Last asked Mar 2026Were you asked this too?
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  Modeling other agents in a driving simulatorML designIn a simulator used to test a self-driving stack, how do you model the other agents (cars, pedestrians, cyclists)? Compare replaying logged behavior, rule-based agents and learned…

  Last asked Feb 2026Were you asked this too?
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  Reinforcement learning for driving: PPO vs GRPO and a speed-limit rewardML designQuestions on reinforcement learning for a driving policy: 1. How do GRPO and PPO differ? 2. When would you choose a hand-written heuristic reward over a learned reward model, and…

  Last asked Feb 2026Were you asked this too?
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  Remaining path length at every waypoint of a batch of trajectoriesCodingYou get a tensor of trajectories of shape batch, numwaypoints, 2 (x, y per waypoint). Return a tensor of shape batch, numwaypoints with a suffix sum for every waypoint: the…

  Last asked Feb 2026Were you asked this too?
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  Single-threaded scheduler for one-shot, delayed and periodic tasksCodingBuild a scheduler that runs on a single thread and accepts three kinds of jobs: run once now, run once after a delay, and run every N units of time. Decide how the clock moves…

  Last asked Jan 2026Were you asked this too?
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  Automatic emergency braking logic in PythonCodingWrite a simple automatic braking function in Python: given the vehicle's state and what is ahead of it (for example speed and distance to an obstacle), decide whether and how hard…

  Possibly retiredWere you asked this too?
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  Check an array is a permutation of 0 to n-1CodingImplement iszerobasedpermutation(nums: listint) - bool. Given an integer array nums of length n, return True if it contains every integer from 0 to n - 1 exactly once, and False…

  Possibly retiredWere you asked this too?
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  Memory allocator with malloc, free and coalescingCodingManage one arena of size bytes, addressed by offset from 0. You hand out and take back ranges of it, like malloc and free in C. Nothing is stored in the arena itself; track it in…

  Possibly retiredWere you asked this too?
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  RNNs, LSTMs, Transformers and model predictive controlML designA technical conversation on the sequence models in your projects: how RNNs, LSTMs and Transformers differ, why LSTMs help with long sequences, what attention buys you, and when…

  Possibly retiredWere you asked this too?
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  Cache with expiry, priority and LRU evictionCodingImplement a fixed-capacity key-value cache, PriorityExpiryLRUCache. Every item stores a value, an integer priority, and an expiry time. When a new key arrives and the cache is…

  Possibly retiredWere you asked this too?
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  Attention and a small Transformer with a hand-written backward passCodingImplement scaled dot-product attention and a small autoregressive Transformer block from scratch, including the causal mask. Then write the backward pass by hand (no autograd) for…

  Possibly retiredWere you asked this too?
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  Distance to the nearest waypoint along a routeCodingYou are writing part of a car's navigation software. A route is a polyline: an ordered list of 2D waypoints coordinates, connected by straight segments from each waypoint to the…

  Possibly retiredWere you asked this too?
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  Closest latency pairs by minimum absolute differenceCodingA monitoring service records latency readings (whole milliseconds) and wants to flag readings that are suspiciously close to one another. Implement minabsdiffpairs(latencies:…

  Possibly retiredWere you asked this too?
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  Rank vehicles by peer-to-peer update contributionCodingA fleet of electric vehicles receives over-the-air software updates split into fixed-size chunks. Chunks come from the distribution server over cellular data, which is expensive…

  Possibly retiredWere you asked this too?