Deep ML practice, projects, and interview prep

Learn machine learning by actually doing it

QuiddityML teaches the full ML stack with a clear roadmap, short lessons, 11 types of hands-on exercises, spaced repetition, interview questions, and portfolio projects, with the math taught where it comes up. Learn it once, then keep it.

hands-on exercises
11,000+
App Store rating
5.0 ★
QuiddityML Pro
46%
ML Foundation
Unit 1 of 5
✓Welcome
2How Machines Learn
3Loss and Gradients
QuiddityML axolotl mascot
11 exercise typesRecognize, connect, debug, and build-from-scratch.
Spaced repetitionConcepts return before you forget them
ML interview prepQuestions after every unit
Portfolio projectsBuild work you can show
Why QuiddityML

Build understanding that holds

Not just watching and forgetting. QuiddityML takes you through structured tracks, hands-on coding exercises, and built-in spaced repetition that makes sure what you learn actually sticks.

Practice Beyond Recall

Reading or watching videos is passive. QuiddityML makes you actually do the work. Progress through 4 tiers of difficulty, from recognizing concepts to implementing models from scratch, with live feedback on every answer.

Smart Review That Follows Your Weak Spots

QuiddityML tracks how well you know each concept and reminds you to review at exactly the right moment. No more forgetting what you learned last week.

Beginner Friendly, Research Depth

Start from the basics, then work through real equations, code, diagrams, and model behavior deeply enough to read papers and build your own systems.

How a session works

Learn it. Test it. Keep it

Each concept moves through the same loop: understand it, use it, then review it before it fades.

1
Study the concept

Each concept starts with slides: clear explanations, diagrams, equations, and worked code examples. Real depth, not bullet points. You read and understand before anything gets tested.

Diagrams & figuresMath notationWorked examplesCode walkthroughs
2
Do the exercises

After each concept, exercises push you past basic recall. Spot bugs, fill in implementations, write code from scratch. You can't just skim your way through.

11 exercise types4 tiers of demandReal PyTorch code
3
Review before you forget

Spaced repetition schedules each concept based on how well you actually did, not just that you finished it. Struggled on an exercise? It comes back in a day. Nailed it? It waits weeks. Your review queue is built entirely from your own results.

Performance-driven schedulingUnique to youDaily review queue
Exercise engine

Practice should look like the work itself

QuiddityML exercises are built around the things ML people actually do: recognize concepts, connect math to code, debug broken systems, and build models from scratch.

Recognize

gradient
Concepts become easier to use when you can name them in context.
Learn to recognize ML concepts wherever they show up: in code, equations, diagrams, model behavior, and interview questions.

Connect

The map turns isolated facts into working intuition.
Build the links between ideas so gradient descent, backpropagation, optimizers, and loss curves stop feeling like separate topics.

Debug

# inside attention
scores = q @ k.transpose(-2, -1)
scores = scores / math.sqrt(d_ff)
weights = softmax(scores)
loss diverging, nan detected
lossnan
accuracy12%
The fastest fix starts with knowing what the symptoms mean.
Debug broken training runs by tracing the failure through code, tensors, metrics, and model assumptions.

Build

You understand the architecture when you can rebuild it from first principles.
Build models from scratch so the architecture becomes code you can reason about, modify, and explain.

Try real exercises, right here

These are real exercises from the app. 11,000+ more are waiting.

Curriculum

From fundamentals to the frontier

Start with math and ML foundations, then branch into NLP, retrieval, vision, RL, generative models, interpretability, safety, and many more areas of modern AI.

ML Foundation Optimization, neural networks, backpropagation, and the core concepts behind modern ML.
Intro to NLP Tokenization, embeddings, language models, and attention.
Retrieval & Search Ranking, embeddings, and search-powered products.
RL Foundation Rewards, value functions, policies, and exploration.
Mathematical Toolkit Notation, logarithms, combinatorics, and Big-O.
After each unit

Turn understanding into interview answers and project work

ML interview prep

Every unit ends with questions tied to the material you just learned: concepts, coding, system design, and follow-ups.

Not a generic prep listMatched to the unitUseful for ML engineering and research interviews
Portfolio projects

Build small, real projects that prove you can apply the ideas outside the lesson.

Real codeScoped to your trackMade to explain on a CV or in an interview
Real reviews

What people say on the App Store

These are copied word for word from the App Store, where we cannot edit or remove them. Rated 5.0 across every review so far. Read them at the source: App Store reviews.

★★★★★
The best app I've found!

Such an amazing and helpful app! I wish everyone knew about it!

Hayley Wank · App Store, Sep 22, 2026
★★★★★
This is the bomb diggity

I've really been enjoying QuiddityML! The lessons are clear, interactive, and make complicated machine learning concepts much easier to understand. I especially like the hands-on exercises and the way the app encourages you to actually think through problems instead of just memorizing information

dandyandy86 · App Store, Sep 13, 2026
★★★★★
Love it!

I've been trying to get into machine learning for months, and there's just so much content and so many resources that it's overwhelming. Some have way too much theory, some don't have enough, courses are too long and outdated, and books are just boring. I honestly love this app. It makes learning ML actually fun, and the spaced repetition thing is brilliant. I'm surprised no one else did it before. The lessons are clear, visual, and broken into pieces that actually build on each other instead of dumping theory on you all at once. I also really like that it explains the "why" behind concepts, not just definitions, and has different exercises that build on each other and actually make you learn how to code these things. Also the axolotl is adorable

Jess codes · App Store, Sep 2, 2026
★★★★★
Never seen anything like this

I've been looking for ways to customize an AI to execute specialized functions for my needs. I'm pretty sure this app just came out, but my goodness, this is exactly what I've been looking for. It teaches every step to building an AI. It literally goes through the basics to applying advanced concepts. The creator has been open and responsive to feedback, so the app is constantly being updated. Love this app and I can't believe I landed on it.

Iknowyourtrix · App Store, Sep 7, 2026
★★★★★
Highly recommended

Fun and easy way to learn machine learning. Very comprehensive.

Ma*i*a · App Store, Sep 2, 2026
How it compares

QuiddityML vs books, YouTube, and courses

Every option below can teach you ML, and each is good at something. Here is what each one gives you, side by side.

QuiddityMLBooksHands-On ML, ISLRYouTubeStatQuest, 3Blue1BrownMOOCsAndrew Ng on Coursera, fast.aiInteractive sitesDataCamp, Brilliant, Kaggle Learn
Spaced repetitionConcepts you're shaky on come back before they fade✓✗✗✗Brilliant adaptive practice, DataCamp review practice, Kaggle no
11 hands-on exercise typesWrite, debug and read real code and math, not just multiple choice✓end-of-chapter exercises and labs✗weekly quizzes and labscoding, multiple choice, order the lines
Clear roadmapEvery concept in order, so you can see what's next and where your gaps are✓within one book✗within one specializationDataCamp career tracks, others partial
Interview questions every unitPractice explaining concepts the way interviews ask✓✗separate videosseparate coursesseparate courses
A project at the end of every trackBuilt from concepts you've already practiced✓one project (Hands-On ML)✗fast.ai yes, Coursera labsDataCamp guided, Kaggle on your own
Math in contextStart building sooner, and learn the math where it comes up✓explained, you build on your ownexplains, no buildingfast.ai yes, Andrew Ng optional videospartial
Instant feedbackSee why an answer is wrong as soon as you submit it✓✗✗auto-graded quizzes and labs✓
5-minute lessonsEasy to fit into a busy day✓chapters10–30 min videoshours a week✓
Web, iPhone and MacProgress syncs across devices✓paper or ebookwatch onlyquizzes on mobile, labs on a computerDataCamp and Brilliant yes, Kaggle no
One app, 12 tracksPython and PyTorch through NLP and vision✓one topic per bookscatteredseparate coursespartial
Pricing

Start free. Pay only if you want everything.

No card needed to start. Spaced repetition, the review queue, and progress tracking are included in both plans.

Free
$0

Enough to learn the foundations properly and decide if this is for you.

The full Python, PyTorch, and Math tracksUnit 1 of every other track3 hearts, one refills every 30 minutesConcepts unlock in order
Pro
$19.99/month
or $149.99/year with a 7-day free trial ($12.49/month)

Everything, in any order, with no hearts to run out.

All tracks and all unitsUnlimited heartsLearn in any orderCancel any time
QuiddityML axolotl mascot

Become the person who understands it deeply enough to change it

Move from recognizing ML terms to reasoning through the math, debugging the code, explaining the tradeoffs, and building systems of your own.

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