https://vibeengines.com/ Free, interactive learning for AI and backend engineers — handbooks, system-design walkthroughs, algorithm games, and developer tools. No sign-up. en Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/uber-system-design https://vibeengines.com/systemdesign/uber-system-design System Design Build a planet-scale ride-hailing system step by step. Learn how to handle real-time location tracking, matching algorithms, scalability, and payments through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/url-shortener-system-design https://vibeengines.com/systemdesign/url-shortener-system-design System Design Build a URL shortener (think Bitly or TinyURL) step by step. Learn how to mint unique short codes with base62, make the read-heavy redirect path sub-millisecond with caching, shard billions of mappings, and track clicks asynchronously through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/twitter-system-design https://vibeengines.com/systemdesign/twitter-system-design System Design Build Twitter's news feed step by step. Learn the social graph, why fan-out on write beats read-time merging, how a precomputed timeline cache makes feed reads O(1), how ranking surfaces the best tweets, and how a hybrid model solves the celebrity problem — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/youtube-system-design https://vibeengines.com/systemdesign/youtube-system-design System Design Build a planet-scale video platform step by step. See how raw uploads become an adaptive-bitrate ladder through an async transcoding pipeline, how a CDN serves immutable segments from the edge, how tiered blob storage holds exabytes affordably, and how view counts stay async — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/rate-limiter-system-design https://vibeengines.com/systemdesign/rate-limiter-system-design System Design Build a distributed rate limiter step by step. Learn where to put the check, how to key and tier limits, the token-bucket and sliding-window algorithms, why shared atomic counters in Redis avoid race conditions, and the fail-open vs fail-closed trade-off — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/dropbox-system-design https://vibeengines.com/systemdesign/dropbox-system-design System Design Build a file sync engine step by step. See how splitting metadata from bytes, content-addressed block storage with deduplication, delta sync, a push-then-pull notification service, and conflict-safe versioning fit together to keep files consistent across every device — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/ticketmaster-system-design https://vibeengines.com/systemdesign/ticketmaster-system-design System Design Build an event-booking system step by step. Tackle the double-booking problem head-on: seat inventory, short-lived holds with TTLs, exactly-once purchases via ACID transactions, payment sagas with idempotency, and a virtual waiting room that tames the on-sale stampede — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/notification-system-design https://vibeengines.com/systemdesign/notification-system-design System Design Build a multi-channel notification system step by step. See how one API, a message queue and a worker fleet decouple slow third-party delivery, how preferences and quiet hours gate every send, how templates fan out to push, SMS and email, and how delivery tracking, retries, dedup and rate limits keep it reliable — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/typeahead-system-design https://vibeengines.com/systemdesign/typeahead-system-design System Design Build a search typeahead step by step. See how a prefix trie turns search into an O(L) walk, how a prefix-keyed cache answers the skewed common case in under a millisecond, how precomputed top-k ranking surfaces the best ten, how an offline builder keeps suggestions fresh from query logs, and how to personalize and shard — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/message-queue-system-design https://vibeengines.com/systemdesign/message-queue-system-design System Design Build a distributed message queue like Kafka step by step. See how an append-only commit log, partitions keyed for order, consumer groups with server-side offsets, leader/follower replication, controller-driven leader election, retention and compaction, and exactly-once guarantees fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/key-value-store-system-design https://vibeengines.com/systemdesign/key-value-store-system-design System Design Build a distributed key-value store like DynamoDB step by step. See how consistent hashing places keys, how replication and tunable quorums (R + W > N) trade consistency for availability, how vector clocks resolve conflicts, and how gossip membership, hinted handoff and read repair keep it alive through failure — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/distributed-cache-system-design https://vibeengines.com/systemdesign/distributed-cache-system-design System Design Build a distributed cache like Redis or Memcached step by step. See how cache-aside shields the database, how consistent hashing shards across nodes, how TTL and LRU/LFU eviction bound memory, how replication and invalidation keep it correct, and how to survive cache stampedes and hot keys — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/news-feed-system-design https://vibeengines.com/systemdesign/news-feed-system-design System Design Build a social news feed step by step. See how the social graph, pull vs push fan-out, a precomputed feed cache, relevance ranking, the hybrid model that tames the celebrity problem, blending multiple content sources, and cursor pagination fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/web-crawler-system-design https://vibeengines.com/systemdesign/web-crawler-system-design System Design Build a distributed web crawler step by step. See how a URL frontier drives the fetch–parse–enqueue loop, how a bloom-filter seen-set stops infinite re-crawling, how politeness and robots.txt keep you a good citizen, how DNS caching and content dedup remove bottlenecks, and how to shard the frontier by host and dodge traps — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/google-docs-system-design https://vibeengines.com/systemdesign/google-docs-system-design System Design Build a real-time collaborative editor step by step. See how edits become tiny operations, how OT and CRDTs resolve concurrent edits so every copy converges, how ops broadcast over WebSockets, how an op log plus snapshots give history and recovery, and how presence, offline sync and per-document sharding fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/job-scheduler-system-design https://vibeengines.com/systemdesign/job-scheduler-system-design System Design Build a distributed job scheduler (cron at scale) step by step. See how a durable job store indexed by run time, a due scanner, a ready queue feeding a worker pool, idempotent at-least-once execution, leader election to avoid double-fires, retries with backoff and a DLQ, and time-wheel sharding fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/netflix-system-design https://vibeengines.com/systemdesign/netflix-system-design System Design Build a planet-scale video streaming service step by step. See how the play path splits authorization from byte delivery, how origin storage and CDN edges serve immutable segments, how an adaptive-bitrate ladder adapts to any connection, how a parallel transcoding pipeline builds it, and how Open Connect, recommendations and QoE events fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/instagram-system-design https://vibeengines.com/systemdesign/instagram-system-design System Design Build a photo-sharing app step by step. See how splitting media from metadata, a CDN for immutable images, async image processing, a precomputed feed cache, asynchronous like/view counters, TTL-based ephemeral stories, and sharding fit together to serve billions of photos — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/pastebin-system-design https://vibeengines.com/systemdesign/pastebin-system-design System Design Build a text-paste service step by step. See how base62 key generation, separating metadata from blob storage, a cache and CDN for the read-heavy immutable path, TTL expiration, privacy flags and size limits, and async analytics fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/distributed-id-generator-system-design https://vibeengines.com/systemdesign/distributed-id-generator-system-design System Design Build a distributed unique ID generator like Twitter Snowflake step by step. See why auto-increment and UUIDs fall short, how a 64-bit ID packs a timestamp, machine id and sequence to stay collision-free and time-sortable without per-ID coordination, how machine ids are assigned, and how clock skew is handled — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/search-engine-system-design https://vibeengines.com/systemdesign/search-engine-system-design System Design Build a web search engine step by step. See how an inverted index turns search into list lookups, how query parsing mirrors indexing, how an offline indexer builds postings, how BM25 and PageRank rank results, and how document-sharded scatter-gather, result caching and a fresh index scale it to billions of pages — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/ad-click-aggregator-system-design https://vibeengines.com/systemdesign/ad-click-aggregator-system-design System Design Build a real-time ad click aggregator step by step. See how a thin ingest API and event stream absorb millions of clicks a second, how a stream processor aggregates into time windows, how dedup keys give exactly-once counts, how a raw event lake and batch recompute reconcile the numbers, and how fraud filtering and watermarks handle the sharp edges — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/airbnb-system-design https://vibeengines.com/systemdesign/airbnb-system-design System Design Build a lodging marketplace step by step. See how listings and geo search with filters, per-listing availability calendars, atomic booking that never double-books, payment hold-and-capture with idempotency, event-driven reviews and reindexing, and read replicas fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/slack-system-design https://vibeengines.com/systemdesign/slack-system-design System Design Build a team chat app step by step. See how channel messaging and per-channel history, real-time delivery over WebSockets with a session registry, cross-server fan-out via pub/sub, ephemeral presence and typing, message search, unread counts and notifications, and channel sharding fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/google-maps-system-design https://vibeengines.com/systemdesign/google-maps-system-design System Design Build a mapping and navigation service step by step. See how pre-rendered map tiles on a CDN, a weighted road graph, A* shortest-path routing, contraction hierarchies for instant long routes, crowdsourced traffic for live ETAs, geocoding, and regional graph partitioning fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/stock-exchange-system-design https://vibeengines.com/systemdesign/stock-exchange-system-design System Design Build a stock exchange matching engine step by step. See how an in-memory order book with price-time priority matches orders, how pre-trade risk checks guard the core, how a single sequencer and single-threaded engine give deterministic low-latency matching, and how market-data feeds, journaling/replay, clearing and symbol partitioning fit together — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/payment-system-design https://vibeengines.com/systemdesign/payment-system-design System Design Build a payment system like Stripe step by step. See how a payment is modeled as a state machine of authorize and capture, how idempotency keys prevent double-charges, how a double-entry ledger keeps every cent auditable, how tokenization shrinks PCI scope, and how async webhooks, reconciliation and a durable retryable worker handle slow banks and failure — through an interactive diagram that grows with each concept. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/algorithm/quicksort https://vibeengines.com/algorithm/quicksort Algorithm See quicksort actually work — then drive it. Watch the pivot partition an array in place, smaller-left and larger-right; pick your own pivot and feel how its position sets the balance; then feed it an already-sorted list and watch a fixed pivot melt down to O(n²) — and fix it with one random line. Three acts — watch the pivot, pick the pivot, break the worst case — plus full theory, a worked trace and a quiz. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/algorithm/merge-sort https://vibeengines.com/algorithm/merge-sort Algorithm Don't read about merge sort — play it. Watch single-element runs cascade upward into one sorted array, merge two sorted halves by hand by always taking the smaller front, then prove the payoff: O(n log n) on sorted, reversed and shuffled input alike — the guarantee quicksort can't make. Three acts — watch the cascade, merge two runs, prove the guarantee — plus full theory, a worked trace and a quiz. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/lab/gradient-descent https://vibeengines.com/lab/gradient-descent Lab Don't read about gradient descent — play it. Roll a ball into the valley of a loss landscape by hand and waste steps, then let the algorithm read the slope and step downhill on its own. Crank the learning rate until it overshoots and explodes, dial it down until it crawls, then switch on momentum to escape a local minimum. Four acts — descend it, follow the gradient, tune the learning rate, escape the trap — plus the full theory, a worked trace and a quiz. Mon, 22 Jun 2026 00:00:00 GMT https://vibeengines.com/algorithm/dijkstra-last-mile https://vibeengines.com/algorithm/dijkstra-last-mile Algorithm Don't watch Dijkstra's algorithm — play it. Drive a courier through a living isometric city, lose the fastest route to your own instincts, then meet the Dispatcher who floods the streets to find the optimal path every time. Four acts: drive it, watch the frontier, predict the next lock, then break it with a negative cycle — with the full theory, a worked trace, and a quiz. Sun, 21 Jun 2026 00:00:00 GMT https://vibeengines.com/algorithm/binary-search https://vibeengines.com/algorithm/binary-search Algorithm Don't memorize binary search — play it. Crack a vault of sorted dials, burn through guesses by instinct, then meet the Halver who throws away half the search space with every single look and finds any value in O(log n). Three acts — crack it, watch the window collapse, predict the midpoint — plus the full theory, a worked trace and a quiz. Sun, 21 Jun 2026 00:00:00 GMT https://vibeengines.com/algorithm/bfs-flood https://vibeengines.com/algorithm/bfs-flood Algorithm Don't memorize breadth-first search — play it. Find your own way through a maze, then release the flood that spreads from the start in rings and touches the exit by the shortest path every time, then watch depth-first search dive deep and miss it. Three acts — navigate it, release the flood, BFS vs DFS — plus the full theory, a worked trace and a quiz. Sun, 21 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/prompting-handbook https://vibeengines.com/handbook/prompting-handbook Handbook A friendly, hands-on field guide for everyday humans — learn the CRISP framework, spot bad prompts, practice with real recipes, play a drag-and-drop game, and test yourself with a quiz. No code required. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/llm-interview https://vibeengines.com/handbook/llm-interview Handbook Twenty topics every senior AI engineer should be able to reason about live — from eval pipelines to reliability patterns for generative systems. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/senior-ai-engineer https://vibeengines.com/handbook/senior-ai-engineer Handbook 60 questions across architecture, production incidents, agentic systems, RAG, evals, cost, safety, and leadership — what staff-level AI interviewers actually probe for. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/angular-interview https://vibeengines.com/handbook/angular-interview Handbook A visual handbook covering components, change detection, RxJS, signals, routing, forms, performance, and testing — what interviewers actually probe for in senior Angular roles. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/python-interview https://vibeengines.com/handbook/python-interview Handbook Fundamentals to advanced: data structures, OOP, iterators & generators, the GIL, asyncio, memory, testing, and the standard library — a visual walk through everything a Python interview touches. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/llm-evals-interview https://vibeengines.com/handbook/llm-evals-interview Handbook Golden sets, LLM-as-judge, regression testing, offline vs online evals, RAG evals, agent evals, red-teaming, and observability — demystified for interviews and production. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/agent-evals https://vibeengines.com/handbook/agent-evals Handbook A self-contained handbook on evaluating AI agents — theory, interactive widgets, and practical guidance. Trajectory evals, tool-use scoring, LLM-as-judge, observability, and reliability for PMs, engineers, and founders. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/system-design-fundamentals https://vibeengines.com/handbook/system-design-fundamentals Handbook The load-bearing ideas behind every distributed system — the CAP theorem and consistency models, concurrency and locking, partitioning and replication, and consensus and coordination — each tied to a real worked design you can study interactively. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/cap-theorem https://vibeengines.com/handbook/cap-theorem Handbook What a distributed system can promise when the network splits — CP vs AP, why "CA" is a myth, PACELC, and the full spectrum from linearizable to eventual consistency. Part of System Design Fundamentals. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/concurrency-and-locking https://vibeengines.com/handbook/concurrency-and-locking Handbook How overlapping operations stay correct — race conditions, optimistic vs pessimistic locking, the four isolation levels and their anomalies, MVCC, and distributed locks with fencing tokens. Part of System Design Fundamentals. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/partitioning-and-replication https://vibeengines.com/handbook/partitioning-and-replication Handbook How one dataset becomes many — range vs hash partitioning, consistent hashing and virtual nodes, hot partitions, replication topologies, replication lag, and quorums. Part of System Design Fundamentals. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/handbook/consensus-and-coordination https://vibeengines.com/handbook/consensus-and-coordination Handbook How nodes that can crash still agree on one truth — majority quorums, Raft and Paxos, leader election, two-phase commit vs the saga pattern, and idempotency for exactly-once effects. Part of System Design Fundamentals. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/roadmap/prompt-engineering https://vibeengines.com/roadmap/prompt-engineering Roadmap A visual transit-map roadmap from tokens and CRISP through chain-of-thought, RAG, and agent prompting to production monitoring. 18 stations across 3 tracks — interactive, free, your own pace. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/consistent-hashing https://vibeengines.com/tools/consistent-hashing Tool An interactive consistent-hashing playground. Add and remove nodes, tune virtual nodes, and watch keys remap around the ring in real time — see exactly why consistent hashing moves only K/N keys instead of reshuffling everything, and how virtual nodes smooth out hotspots. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/capacity-estimator https://vibeengines.com/tools/capacity-estimator Tool Slide DAU, requests per user, payload size and read/write ratio and watch QPS, storage per year, bandwidth, shard count and cache memory recompute live — every number with the formula behind it. The napkin math interviewers expect, made interactive. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/rag-chunking https://vibeengines.com/tools/rag-chunking Tool Drop in any text and compare chunking strategies — fixed-size, recursive, by-sentence, by-paragraph — with overlap highlighted and an estimated token count per chunk. Stop guessing your chunk size; see exactly how your RAG pipeline will split a document. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/context-cost-planner https://vibeengines.com/tools/context-cost-planner Tool Add a system prompt, tool definitions, conversation history and retrieved context, then see your context window fill up and the cost per call — plus the bill at 1k and 1M requests — across model price tiers. An architecture planner, not a toy token counter. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/quorum-explorer https://vibeengines.com/tools/quorum-explorer Tool Dial the replica count and the read/write quorum sizes and see at a glance whether reads are guaranteed strongly consistent (R + W > N), how many node failures you can survive, and where you land on the latency–availability spectrum. The tunable-consistency intuition, made tactile. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/availability-calculator https://vibeengines.com/tools/availability-calculator Tool Chain dependencies in series and parallel and watch the combined availability — and the yearly downtime it implies — fall out. Unlike single-service "nines" calculators, this one models the dependency graph, so you see how one shaky component drags down the whole system. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/llm-judge-builder https://vibeengines.com/tools/llm-judge-builder Tool Define your evaluation criteria and a scoring scale, then generate a clean, copy-pasteable LLM-as-judge prompt you can drop into your eval pipeline — with the common pitfalls (position bias, verbosity bias, ties) called out. Turns eval theory into a prompt you can ship. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/tools/tool-schema-designer https://vibeengines.com/tools/tool-schema-designer Tool Compose a tool/function definition field by field — name, description, parameters, required flags — and export valid tool-use JSON for the Claude and OpenAI formats, with the JSON Schema generated for you. Stop hand-writing function-calling schemas and fighting silent validation errors. Sat, 20 Jun 2026 00:00:00 GMT https://vibeengines.com/systemdesign/whatsapp-system-design https://vibeengines.com/systemdesign/whatsapp-system-design System Design Build a real-time messaging system step by step. See how persistent WebSockets, a session registry, offline inbox queues, the ✓✓ delivery receipts, group fan-out, media on a CDN, and end-to-end encryption fit together — through an animated, live chat-driven diagram that grows with each concept. Mon, 15 Jun 2026 00:00:00 GMT