EARLY ACCESS/13 of 100 spots claimed. Includes 1:1 mock interview & resume review/Claim your spot →
Structured interview prep

Build the skill.
Land the offer.

System design, coding patterns, and low-level design in one structured track, built around how companies actually interview.

Choose your path Browse all courses
Platform overviewlive
3
Learning paths
6
Full courses
100+
Lessons & problems
87/100
Early access spots
Now available
AI
AI course
RAG, Agent Orchestration, Evals & MCP
01 · Choose a path

Three tracks, built for where you actually are.

Each path sequences the right courses in the right order. No guessing what to study next.
Path 012 courses · ...

Student Starter Path

CS students · Career switchers

Build strong fundamentals in coding patterns and databases. The core skills every software role expects on day one.

  • Coding Interview Patterns
  • Database Fundamentals
Start this path
Path 023 courses · ...

Junior Developer Path

Early-career · 0–3 yrs

Level up from writing features to designing them. Coding patterns, object-oriented design, and databases in one structured track.

  • Coding Interview Patterns
  • Low Level Design
  • Database Fundamentals
Start this path
Path 034 courses · ...

Interview Prep Path

Experienced · FAANG-ready

Comprehensive prep for interviews at top tech companies. System design, low-level design, coding, and databases, end to end.

  • System Design Interview
  • Coding Interview Patterns
  • Low Level Design
  • Database Fundamentals
Start this path
02 · Inside the course

Practice with instant feedback.

Answer interview-style system design questions with text. Get a graded response in seconds, with strengths, gaps, and exactly what a strong answer looks like.

  • 01
    Stepwise question flow
    Clarifying questions, functional and non-functional requirements, API contract, data model. The way real interviews unfold.
  • 02
    AI feedback, scored
    Tech accuracy, completeness, clarity, graded with specific strengths and gaps.
  • 03
    Live diagram canvas
    Sketch services and edges as you answer. Each node is reviewed alongside your response.
buildtooffer / practice / rate-limiter
QUESTIONS
✓Clarifying Q’s
2Functional req’s
3Non-functional
4API contract
5Data model
Q2 · FUNCTIONAL
Core requirements for a distributed rate limiter?
1. Rate limit per API request
2. Configurable per user / API key
3. …
DIAGRAM · 3 NODES
clientapi-gwredis
Get Feedback
FEEDBACK · 1.4s
4.0
/ 10
NEEDS WORK
Solid start, missed the response contract.
Accuracy
5/10
Complete
3/10
Clarity
6/10
✓2 Strengths
Identified per-key configurability.
!2 Gaps
Missing 429 + rate-limit headers.
coding / stacks / valid-parentheses
Auto-saved
PATTERNS
Stacks5
Intro to Stacks
Valid Parentheses
Solution: Valid…S
Min Stack
Two Pointers3
Sliding Window4
Tree DFS4
02 / 5·STACKS

Valid Parentheses

Easy~15 min
ASKED ATGoogleMetaAmazon+9
Given a string s of brackets, return whether it is valid: opens close in the right order, same type.
EXAMPLE 1
Ins = "()[]{}"
Outtrue
stringstack
Python ▾
FormatCopy
1class Solution:
2 def isValid(self, s):
3 stack = []
4 pairs = {')':'(', ']':'['}
5 for c in s:
6 if c in pairs:
7 if stack.pop() != pairs[c]:
8 return False
9 return not stack
Accepted3/3 PASS
38 ms · 14.1 MB
123
⌘↵ RUN
RunSubmit ✓
03 · Coding practice

A real workspace, not a video lecture.

Curated patterns, stepwise problem statements, an in-browser editor, and instant feedback against hidden test cases. The way interviews actually work.

  • 01
    Pattern-organized library
    Sliding window, two pointers, DFS. Problems grouped by the technique you’re learning, not random shuffles.
  • 02
    In-browser editor + runner
    Python, JavaScript, Java, C++. Run, submit, and see runtime in seconds, no setup needed.
  • 03
    Hints that don’t spoil it
    Progressively-revealing hints. Reveal one, try again. Only see the full solution if you want to.
04 · AI engineering

Treat AI as a backend discipline.

RAG, agent orchestration, evals, MCP. Concepts paired with diagrams you can actually read, lab files you run locally, and interactive visualizers for embeddings, vector search, and more.

  • 01
    Concepts with diagrams
    Sequence diagrams, decision trees, and flow charts rendered inline, not pasted-in screenshots.
  • 02
    Downloadable lab files
    Pull the notebook and run it in your own environment. Real keys, real models, real failures, the way it works on the job.
  • 03
    Hosted labs
    No local setup? Launch a vector DB sandbox, embed a corpus, and query it in the browser in seconds.
ai / rag / retrieval-augmented-generation
FREE PREVIEW
CHAPTERS
Foundations4
RAG6
Embeddings
Retrieval pipeline
Chunking strategiesLAB
Hybrid search
Agents & MCP5
Evals4
Inference infra3
CH 02 · RAG / 02

The retrieval pipeline, end to end

A query becomes an embedding, hits a vector index, and the top-k matches get re-ranked before they reach the model. Every hop trades off latency, recall, and cost.

SEQUENCE DIAGRAM
clientembed-svcvector-dbre-rankqueryembed[768]top-50 idstop-5 chunks
RELATEDChunkingHybrid searchEvals
LABS · 3 AVAILABLEREADY
HOSTEDVECTOR DB
pgvector sandbox
Pre-loaded with 50k Wikipedia chunks. Run queries in-browser.
pg-15 · 4GBLaunch →
.IPYNBDOWNLOAD
rag-pipeline.ipynb
End-to-end RAG with re-ranking. Bring your own API key.
12 cells · 4.2 KBDownload
.PYEVAL HARNESS
ragas-eval.py
faithfulness · relevanceDownload
low-level-design / patterns / observer
BEHAVIORAL
CLASS DIAGRAM · OBSERVER
−FIT+
«interface»Subject+ attach(o)+ detach(o)+ notify()«interface»Observer+ update(s)0..*observersNewsPublisher− headlines: []+ publish(h)+ notify()MobileApp− user: User+ update(s)− render()realizesrealizes
Java ▾Observer.java
SOLID
1interface Observer {
2 void update(String state);
3}
4 
5class NewsPublisher {
6 private List<Observer> obs;
7 public void attach(Observer o) {
8 obs.add(o);
9 }
10 public void notify() {
11 for (Observer o : obs)
12 o.update(state);
13 }
14}
Open/Closed✓DIP✓
Run example →
05 · Low Level Design

Design like an engineer.

SOLID, design patterns, and interview-style design problems. Class diagrams that map straight to runnable code, not abstract boxes and arrows.

  • 01
    SOLID, applied
    Each principle taught with a before-and-after refactor. Spot the smell, fix it, ship it.
  • 02
    20+ design patterns
    Singleton, Factory, Strategy, Observer, Decorator. Each one with its intent, structure, working code, and when not to reach for it.
  • 03
    Interview-style design problems
    Design a parking lot, Splitwise, a movie booking system. From requirements to class diagram to code.
06 · Only here

See the algorithm execute.

Every solution comes with a synchronized walkthrough: code, data structure, call stack, and narration moving in lockstep. Scrub, pause, change speed.

APPROACH1Recursive DFSO(n)2Iterative + Stack3BFS + Queue
PATH SUM · TREE DFS
CODE · CURRENT LINESTEP 3 / 9
1class Solution:
2    def hasPathSum(self, root, t):
3        if not root: return False
4        if not root.left and not root.right:
5            return t == root.val
6        return (self.hasPathSum(root.left,
7                t - root.val) or ...
CURRENT NODE
root.val = 4
REMAINING TARGET
15
CALL STACK
5(t=20)→4(t=15)
VISUALIZATION · BINARY TREE
−FIT+
54811134
On call stackVisitedNot yet
STEP 3

We recurse left. Passing targetSum = 20 − 5 = 15 down. Node 4 is now on the call stack. Not a leaf, so we keep going.

Step 1 · InitSTEP 3 · Recurse leftStep 9 · Return
ELSEWHERE
Video lecture

Watch someone else solve it. Pause. Rewind. Hope it sticks.

ELSEWHERE
Static diagram

A finished tree. No motion, no state, no sense of time.

HERE
Live walkthrough

Code, data, and stack move together. Scrub, slow it down, replay. See the algorithm.

Early Access · 87 / 100 spots open

Because landing the job takes more than code.

The first 100 learners get hands-on career support alongside the curriculum. No extra cost.

13 claimed87 remaining
Sign up to claim your spot

Benefits unlock after you complete 80% of your chosen path. Claim within 3 months of enrollment.

01
1:1 Mock Interview

Live session with a senior engineer from a top product company. Clear, actionable feedback on what to improve.

02
Resume & LinkedIn Review

Detailed written feedback focused on what recruiters and hiring managers actually look for.

03
Direct access to instructors

Ask about offers, skill gaps, or projects, and get answers from engineers who navigated the same calls.

04
Resume sharing in our network

Strong learner profiles get shared when relevant roles come up. For learners we’ve seen put in the work.

07 · All courses

Or pick a single course.

SD
System Design InterviewBest Seller
Scalability, distributed systems, real architectures
Intermediate
-
-
CP
Coding Interview PatternsBest Seller
Two pointers, sliding window, DP, graphs
Intermediate
-
-
LD
Low Level DesignEssential
OO design, patterns, software architecture
Intermediate
23 lessons
-
DB
Database FundamentalsPopular
Design, transactions, indexing, distributed
Intermediate
-
-
AI
AINew
RAG, Agent Orchestration, Evals & MCP
Intermediate
-
-
AC
AI Coding InterviewNew
AI/ML coding: attention, tokenizers, top-k
Intermediate
-
-
08 · Learners

What it looked like, from their side.

“The system design course was exactly what I needed before my staff-level loops. The 1:1 mock interview and resume review made a real difference in how I framed my impact stories.”
R
Rohit M.
Principal Engineer
“The coding patterns course finally made interview prep click. Two pointers, sliding window, DP, patterns I’d been guessing at, sequenced in the order that actually builds intuition.”
P
Priya S.
Senior Engineer · fintech
“The system design path is the first resource that sequenced things properly. Went from bombing my first FAANG round to converting offers in the same quarter.”
A
Aarav K.
SDE II → Senior
09 · FAQ

Still deciding?

The things people ask us most, answered honestly.

How is this different from Educative, AlgoExpert, or DesignGurus?+

Those are great resources, usually libraries of content. We’re a sequenced curriculum built around how companies actually interview, with hands-on tooling (live runner, stepwise visualizations) so you practice, not just read.

Do I need to subscribe to all courses?+

No. Every course is available individually. Paths are just curated sequences. Follow one, or mix and match.

Who teaches the courses?+

Senior engineers from product companies who’ve been on both sides of the interview loop.

What’s the refund policy?+

Premium content is delivered instantly, so we generally don’t offer refunds. Try the free lessons across each course before paying.

One path.
One offer.

Start with any path. Browse the curriculum, jump into a course, and see if it fits before you commit.

Start learning See pricing