Persistent key-value store with binary snapshotsCodingImplement an in-memory key-value store whose whole state can be saved to, and restored from, a storage medium that holds a single binary blob. You are given: Implement
Last asked Oct 2026
#storage
+5Design a logging serviceSystem designDesign a central logging service. Every service and host ships its logs; engineers search them within seconds of being written, and logs are kept cheaply for months. Volume is in…Last asked Oct 2026
Design a cache for large model weights on GPU nodesSystem designOn a serverless GPU platform, a container serving a model downloads the model's weights, around 40 GB, every time it starts cold. Design a cache so that the second start of the…Last asked Sep 2026
Document store with drive sync and org ACLsSystem designDesign a document store for law firms, in the style of Google Drive or a deal data room: organizations keep files and folders, upload and download them, and share them with tight…Last asked Sep 2026
+5Design an S3-like object storage systemSystem designDesign an object storage service like S3. Users store objects of any size, from bytes to many gigabytes, in buckets, and read and write them over an HTTP API at high throughput…Last asked Sep 2026
Choose storage tiers from predicted file accessAI/ML designA cloud storage service keeps each user file in one of several tiers: a hot tier that is fast to read but costs more per GB-month, and archive tiers (in the style of S3 versus…Last asked Aug 2026
Design client-server file sync with a Merkle treeSystem designA server publishes immutable versions of a directory tree. Clients keep a local mirror and sync it to a version they pick. Every file has a content hash, and every directory has a…Last asked Aug 2026
Design unique username registrationSystem designNew accounts each pick one permanent username. A deterministic normalize(name) function, owned by the product, turns valid input into the key that decides uniqueness (case and…Last asked Aug 2026
Design a streaming transcription serviceSystem designUsers either stream audio live or upload a finished recording, and get a transcript back. During a live session they see partial text that may still change, then a stable final…Last asked Aug 2026- Design cloud photo storage with sync across devicesSystem designDesign a cloud photo library: a user takes photos on a phone, they upload, and they appear on the user's other devices; edits and deletes made on any device show up everywhere…Last asked Aug 2026
Design log storage with live tailing of growing filesSystem designProducers keep appending log records to log files at very high volume. Design a system that stores them durably and lets users read files back, including users who read a file…Last asked Aug 2026
Design an audit log serviceSystem designDesign a multi-tenant audit log service for a cloud platform. Every service of the platform records who did what to which resource, and when: a user logging in, a role being…Last asked Jun 2026
+5Design a distributed key-value storeSystem designDesign a key-value store that holds billions of keys across many machines, serves reads and writes with low latency, survives machine and network failures, and lets callers choose…Last asked Jun 2026- Design a core dump collection and analysis systemSystem designDesign a system that collects core dumps from crashing processes across a large fleet of machines, stores them, and helps engineers find and analyze the crashes that matter. -…Last asked Jun 2026
- Design wallpaper sync across a user's devicesSystem designWhen a user sets a wallpaper on one device, their other devices (phone, tablet, laptop) should switch to it. Design that sync. A change must apply immediately on the device where…Last asked Jun 2026
Design a file backup systemSystem designDesign a scalable file backup system. Using basic file system operations (list a directory, read file metadata, read file contents, create directories, write files, delete or move…Last asked Apr 2026- Design a replay system for publish-subscribeSystem designPublishers send messages to topics, and subscribers receive them through a publish-subscribe system. Design a replay feature: a subscriber can ask to receive past messages again…Last asked Mar 2026
- Design a disk-backed key-value store under heavy contentionSystem designDesign a key-value store that keeps its data on local disk and serves many concurrent readers and writers on one machine. Values can be large, and some keys are hot: many clients…Last asked Mar 2026
Design a browser-based graphics editorSystem designDesign a graphics editor that runs in the browser for documents made of layers (shapes, text, images). A signed-in user opens a document, selects, moves, resizes and restyles…Last asked Feb 2026- Design REST APIs for storing JSON filesSystem designDesign the REST API and the backend for a service that stores and serves JSON documents for many users and applications: create, read, update (whole or partial) and delete…Last asked Jan 2026
- Choosing lock granularity for concurrent storageCodingYou are building a storage component, such as an in-memory key-value store or a page cache, that many threads use at once. Choose how coarse or fine its locking should be. Compare…Last asked Jan 2026
- Design a street-level imagery ingestion and storage systemSystem designA fleet of camera vehicles drives the streets and captures large volumes of street-level photos, each with location, time and camera orientation. Design the system that gets the…Last asked Jan 2026
- +6Design DropboxSystem designDesign a file sync service like Dropbox. Users' files stay in sync across their devices and in shared folders. Large files upload reliably over poor connections, only the changed…Last asked Jan 2026
- Serve inventory from disk when it doesn't fit in memorySystem designDesign the software for an inventory server that has spinning disks, no SSD and only a little RAM. Records are keyed by item ID and hold the available quantity, the reserved…Last asked Oct 2025
- Store words for lexicographic range queriesSystem designDesign storage for a persistent set of words that answers range queries: given low, high, inclusive, return every stored word w with low <= w <= high, in dictionary order. Explain…Last asked Oct 2025
- +2Design a Kafka-like distributed message queueSystem designDesign a durable, partitioned log, like Kafka. Producers append messages to topics; many consumer groups read the same topic, each at its own pace; acknowledged messages survive…Last asked Sep 2025
Design an artifact store on Kubernetes and CassandraSystem designA Java web API runs on Kubernetes and stores artifacts in a Cassandra cluster. Each artifact is identified by a name the user chooses, and each name must be created exactly once…Last asked Sep 2025- Design a watch history and resume-playback serviceSystem designDesign the service behind a video platform's watch history: it records which titles each user watched and how far they got, so playback resumes at the right point on any device…Last asked Sep 2025
Design ingestion and search for news articles with imagesSystem designDesign a system that continuously collects news articles from many sources, including the images in them, stores them, and lets analysts search the collection. Cover how articles…Last asked May 2024
Recipe storage with version historyCodingBuild an in-memory store for recipes that keeps every version. Each edit creates a new version; the current recipe and any past version can be read back, and nothing is ever…