The knowledge layer for the age of intelligence.

Learn the systems
by breaking them.

126 interactive builds160 playable lessons208 handbooks550+ free videosfree forever

A free, open-source place to learn AI and system design by doing — take a real system apart in the browser, watch it fall over, and build the intuition that sticks. No sign-up, no paywall. Built in the open by an AI engineer.

netflix.buildlive
The Design Netflix interactive walkthrough — its full architecture diagram Play this build
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just-published.txt
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Daily practice

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A fresh challenge and a lab every day — keep the streak alive.

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Last 13 weeks
TRENDING CAREER TRACK · FLAGSHIP PROGRAM

Become a Forward Deployed Engineer.

Learn the engineering, applied AI and customer judgment needed to move a real deployment from an ambiguous problem to production, measurable value and handoff.

3
entry routes
7
guided phases
1
customer capstone
6
mock interview rounds
Guided pathsNot sure where to start? Pick a goal.All 24 paths →

Every path threads handbooks, system designs, runnable challenges and tools into one ordered course — follow the whole thing or dip in. Free, with your progress saved as you go.

AI EngineeringIntermediate

Become an AI Engineer

For developers building real features on top of LLMs.

17 stops · ~5h 15m
AI EngineeringIntermediate

Adapt to the AI Era

For engineers who want to get more valuable as AI makes code cheap.

11 stops · ~3h 45m
AI EngineeringIntermediate

Ace the AI Engineer Interview

For AI/ML engineer interview loops.

8 stops · ~2h 60m
AI EngineeringIntermediate

Ship an AI Product

For indie hackers and founders shipping AI products solo.

13 stops · ~3h 30m
AI EngineeringAdvanced

Master LLM Evaluation

For engineers who need to prove their AI actually works.

7 stops · ~2h 30m
AI EngineeringBeginner

ML Engineering Foundations

For developers moving from app code into machine learning.

7 stops · ~2h 15m
AI EngineeringIntermediate

Master Context Engineering

For engineers whose agents forget, ramble, or blow the window.

13 stops · ~3h 45m
AI EngineeringAdvanced

The Papers Bootcamp

For engineers who want to read the canonical deep-learning papers in the right order.

22 stops · ~5h 30m
AI EngineeringBeginner

AI for Product Managers

For PMs shipping AI features who want to reason about them without writing code.

14 stops · ~5h
AI EngineeringBeginner

Land Your First Dev Job in the AI Era

For new and bootcamp grads facing "AI is killing junior roles — what do I even learn?"

11 stops · ~3h 45m
AI EngineeringBeginner

Switch Careers into Tech and AI

For career switchers coming from a non-tech field into tech/AI.

10 stops · ~3h 30m
Systems & BackendIntermediate

Pass the System Design Interview

For engineers prepping the system-design loop.

12 stops · ~4h
Systems & BackendAdvanced

Level Up as a Backend Engineer

For backend engineers going deeper on distributed systems.

10 stops · ~3h 15m
Systems & BackendAdvanced

Reliability & Scale (SRE)

For engineers who keep systems up as traffic grows.

8 stops · ~2h 15m
Systems & BackendIntermediate

Become a Forward Deployed Engineer

For engineers who want to own the whole arc — problem to production, at the customer.

63 stops · ~22h 30m
Systems & BackendIntermediate

System Design in 30 Days

For engineers who want to design real systems, not memorize diagrams.

21 stops · ~7h
Systems & BackendAdvanced

Distributed Systems Deep Dive

For engineers who want consensus, replication and consistency in their bones.

20 stops · ~6h 45m
Systems & BackendBeginner

From Sysadmin to DevOps / SRE

For system administrators moving into DevOps, SRE, or platform engineering.

6 stops · ~1h 45m
Systems & BackendIntermediate

From DBA to Data Platform Engineer

For database administrators moving into data engineering / data platform work.

6 stops · ~2h
FoundationsBeginner

Crack the Coding Interview

For the algorithms half of the loop.

11 stops · ~2h 60m
FoundationsAdvanced

Advanced Algorithms & Data Structures

For when the interview basics aren’t enough.

13 stops · ~3h 15m
FoundationsAdvanced

Build an LLM From Scratch

For engineers who want to understand a language model down to the matrix multiply.

20 stops · ~6h 15m
FoundationsIntermediate

The 4-Week Interview Sprint

For engineers with a loop on the calendar and four weeks to prepare.

18 stops · ~5h 45m
FoundationsBeginner

From Manual Tester to SDET

For manual QA testers moving into software development engineer in test (SDET) / automation.

8 stops · ~2h 45m
The core

Interactive builds — take a real system apart.

System designs, AI systems, algorithms and labs you can run, break, and rebuild right in the browser. This is the part you can’t get from a blog.

01
Shelf 01 · Interactive builds

Builds you can break.

System designs, AI systems, algorithms, and labs — every one is a working build. Build Netflix step by step, make the calls, break the system, run the quiz.

★ Featured · Fully interactive

Design Netflix

Build a planet-scale video streaming service. 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.

9 stepsAdvanced⚡ Chaos mode
Start building →
System DesignReal systems, step by step.All 65 designs →
AlgorithmsPlay them, don't memorize them.All 99 algorithms →
N°01
Algorithm N° 01Beginner

Dijkstra: The Last Mile

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.

4 playable acts →
N°02
Algorithm N° 02Beginner

Binary Search: The Vault

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.

3 playable acts →
N°03
Algorithm N° 03Intermediate

Quicksort: The Pivot Pit

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.

3 playable acts →
N°04
Algorithm N° 04Intermediate

Merge Sort: The Cascade

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.

3 playable acts →
N°05
Algorithm N° 05Beginner

BFS: The Flood

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.

3 playable acts →
N°06
Algorithm N° 06Intermediate

A* Search: The Ascent

Don't memorize A* — fly it. Orbit a real 3D mountain, climb it by instinct, then meet the Pathfinder who folds one optimistic guess into Dijkstra's flood so the whole search leans straight at the summit. Four acts in live 3D — climb it, watch the heuristic beat the blind flood, predict the lowest-f pop, then break optimality with a heuristic that lies.

4 playable acts →
N°07
Algorithm N° 07Beginner

Sieve of Eratosthenes: Prime Time

Find every prime under 100 without dividing once. Hit play and watch the multiples fall away in cheerful waves while the primes light up gold — whatever's left standing is prime. A playable take on the 2,000-year-old sieve, with the theory, a worked example and a quiz.

1 playable acts →
N°08
Algorithm N° 08Intermediate

Build Order: DFS & Topological Sort

Don't memorize topological sort — play it. Schedule eight interdependent build tasks by hand and feel the constraints bite, then let a depth-first search dive to the bottom of every dependency and surface a valid build order by reversing its finish times. Three acts — schedule it yourself, watch DFS reverse-post-order it, then add one bad edge and watch it detect the cycle and refuse.

3 playable acts →
N°09
Algorithm N° 09Intermediate

Six Degrees: Union-Find

Don't memorize the Disjoint Set Union — play it. Wire up nine strangers one handshake at a time and watch separate friend circles merge into one, hit a redundant connection and see it refuse to close a cycle, then click any node to run find and watch path compression flatten the tree so the next lookup is instant. Union by rank, path compression and the near-constant O(α(n)) that powers Kruskal's MST — plus full theory, a runnable challenge and a quiz.

3 playable acts →
N°10
Algorithm N° 10Intermediate

The Tournament: Heap Sort

Don't memorize heap sort — watch the tournament play out. See an array read as a binary tree, build it into a max-heap where every parent beats its children so the champion sits at the root, then pluck that root maximum to the end again and again as the sorted region grows from the right. Sift-down, the two phases, and why it's O(n log n) in place with no extra memory — plus full theory, a runnable challenge and a quiz.

3 playable acts →
Run it yourself · no server

Everything here actually runs.

Real Python & TypeScript, executed in your browser — no install, no backend. Every algorithm and system-design page carries an editor like this: read it, edit it, run it, break it.

Try it live on the algorithm pages
Read & follow

The library — handbooks and roadmaps.

Long-form field manuals and visual paths, fundamentals to production. Free, no sign-up.

02
Shelf 02 · The library

Longer form, for when you're ready.

Full-length handbooks and visual roadmaps — agentic AI, LLM evals, RAG, Angular, Python. Free to read, take what you need.

N°01
Handbook N° 01~45 min read

The Prompting 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.

Read handbook →
N°02
Handbook N° 02~60 min read

The Agentic AI Interview Handbook.

Twenty topics every senior AI engineer should be able to reason about live — from eval pipelines to reliability patterns for generative systems.

Read handbook →
N°03
Handbook N° 03~75 min read

The Senior AI Engineer Interview Handbook.

60 questions across architecture, production incidents, agentic systems, RAG, evals, cost, safety, and leadership — what staff-level AI interviewers actually probe for.

Read handbook →
N°04
Handbook N° 04~50 min read

50 Angular Interview Questions.

A visual handbook covering components, change detection, RxJS, signals, routing, forms, performance, and testing — what interviewers actually probe for in senior Angular roles.

Read handbook →
N°05
Handbook N° 05~50 min read

50 Python Interview Questions.

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.

Read handbook →
N°06
Handbook N° 06~55 min read

51 LLM Evals Interview Questions.

Golden sets, LLM-as-judge, regression testing, offline vs online evals, RAG evals, agent evals, red-teaming, and observability — demystified for interviews and production.

Read handbook →
RoadmapsTransit maps through AI.All 31 roadmaps →
N°14
Roadmap N° 1418 stations · ~17h

Forward-Deployed Engineer Roadmap.

A visual transit-map roadmap to the most in-demand AI role of 2026 — the engineer who ships AI where the customer lives. From rapid prototyping, enterprise RAG and integration glue through discovery, customer data wrangling, VPC deployment, security reviews and client evals to stakeholder craft, incidents, proving ROI, and scaling pilots into repeatable production. 18 stations across 3 tracks — The Craft, The Field, The Outcome.

Open roadmap →
N°03
Roadmap N° 0318 stations · ~16h

AI Engineer Roadmap.

A visual transit-map roadmap to become an AI engineer in 2026. From how LLMs work through embeddings, RAG, agents, and fine-tuning to evals, guardrails, inference serving, and observability. 18 stations across 3 tracks — Foundations, Build, Production.

Open roadmap →
N°05
Roadmap N° 0518 stations · ~16h

System Design Roadmap.

A visual transit-map roadmap for system design in 2026. From APIs, databases, caching, and load balancing through sharding, queues, consistent hashing, and consensus to end-to-end designs of Twitter, YouTube, and Uber. 18 stations across 3 tracks — Fundamentals, Building Blocks, Real Systems.

Open roadmap →
N°13
Roadmap N° 1318 stations · ~16h

AI Harness Roadmap.

A visual transit-map roadmap to build an AI harness — the runtime around a model that turns it into an agent. From the messages API, tokens, and structured output through tool calling, the agent loop, context management, memory, and sandboxing to permissions, subagents, evals, observability, and cost control. 18 stations across 3 tracks — Model I/O, the Agent Loop, Production.

Open roadmap →
N°07
Roadmap N° 0718 stations · ~16h

Backend Engineer Roadmap.

A visual transit-map roadmap to become a backend engineer in 2026. From HTTP APIs, SQL, NoSQL, caching, and auth through API design, message queues, testing, and observability to Kubernetes, CI/CD, sharding, and reliability. 18 stations across 3 tracks — Foundations, Core Backend, Production.

Open roadmap →
N°01
Roadmap N° 0118 stations · ~15h

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.

Open roadmap →
CoursesGuided video series, start to finish.All 8 courses →
N°01
11 episodes~2 hours

Build a Real AI App.

A hands-on, build-along course: go from a naive 10-line RAG script that breaks at scale to a production retrieval-augmented app — chunking, embeddings and vector search, hybrid retrieval and reranking, grounded citations, the agent loop, evals, caching and streaming, prompt-injection defense, and deploy + monitoring. Every episode embeds the video and links to the deeper reference on each idea.

Start the course →
N°02
7 episodes~90 min

How LLMs Actually Work.

A visual, first-principles course on what's really happening inside a language model: attention, tokenization, embeddings, mixture-of-experts, fine-tuning and LoRA, RLHF, and diffusion. Seven short episodes, each embedded with a hands-on lab and the deeper reference — the mechanism, not the analogy.

Start the course →
N°03
9 episodes~2 hours

The AI Engineer.

A concepts-first course on the craft of AI engineering: context and memory, embeddings and vector search, tools and agents, hallucination and grounding, the glue around the model, evals, deploy and monitoring, and prompt-injection security. Nine short episodes, each embedded with a hands-on companion and the deeper reference.

Start the course →
N°04
7 episodes~90 min

Data Structures & Algorithms.

The CS-interview core, made visual: hash tables, Big-O, binary search trees, heaps, tries, dynamic programming, and graphs. Seven short episodes, each embedded and paired with an interactive game in the Algorithms arcade — watch the idea, then play it.

Start the course →
N°05
7 episodes~90 min

Concurrency.

The topic that humbles confident engineers, made visual: race conditions, locks and mutexes, deadlock, threads vs processes, the async event loop, concurrency vs parallelism, and the actor model. Seven short episodes, each embedded with the deeper systems reference.

Start the course →
N°06
7 episodes~90 min

How the Internet Works.

Follow one web request from the moment you hit Enter to the pixels on your screen: DNS, IP and packets, TCP, HTTP, HTTPS/TLS, and CDNs. Seven short episodes that trace the whole journey end to end, each embedded with the deeper reference.

Start the course →
N°07
5 episodes~70 min

How Databases Work.

Open the black box: how indexes find one row in a billion, how transactions and the write-ahead log survive a crash, how isolation stops two writes from colliding, how caching absorbs read load, and how vector databases search by meaning. Five short episodes, each embedded with the deeper reference.

Start the course →
N°08
10 episodes~60 min

How Your Computer Works.

The layers under your code, one short episode each: the CPU, floating point, UTF-8, segmentation faults, garbage collection, flash memory, compression, public-key crypto, the speed of light, and what a container really is. Ten visual episodes that turn "it just works" into "I know why."

Start the course →

Stop reading. Break something.

Pick a real system, knock a node out, and watch it reroute — or fall over. That’s the intuition that sticks.

Questions people ask before they start

Is everything on Vibe Engines really free?

Yes. Every system-design build, handbook, roadmap, lab, coding challenge and tool is free, with no paywall, no trial and no upsell. The site is static and open-source; there is nothing to buy.

Do I need an account to use it?

No. There are no accounts and no sign-up. Your progress, streak and flashcard reviews are stored in your own browser (localStorage) and never leave your device — which also means clearing site data resets them, so use the export button on the dashboard if you want a backup.

Where should I start?

Start with one interactive system-design build — break a node and watch the system reroute or fall over. From there, /learn has guided courses by goal or role, and /handbook has the written explanations behind every build.

What is an FDE (Forward Deployed Engineer)?

A Forward Deployed Engineer builds and ships software directly alongside a customer — part engineer, part solutions architect, embedded in the deployment rather than behind a backlog. The FDE Academy track covers the full skill set: system design, AI systems, customer discovery, and the interview loop.

What makes this different from reading a system-design blog post?

The diagrams run. Each build reveals one concept at a time, you can trigger real failure modes and see traffic reroute or drop, and the labs and challenges execute actual Python in the browser. You practise the system rather than read about it.

Is this useful for system design interviews?

Yes — the interactive builds walk the same architectures interviews ask about (Uber, Netflix, a URL shortener, RAG pipelines, inference serving), one decision at a time, with the trade-offs named. Each finishes with a quiz that checks you can defend the design.