01
Target
On a browser step, a live preview of what your app should look like and do once the step is done, made from your own first version. A server step has no picture to aim at, so its checks show what done means. You never have to guess.
Your idea · your project · your curriculum
Learn to code by building the software you actually want.
Describe your app. We build a small first version you can read end to end. Explore it, change it, then rebuild it yourself, one step at a time, with a lesson, a tutor and a check for every step.
Already writing code? The second climb, coming soon: data structures, design patterns and complexity, measured on the code you wrote.
A product of AppKrafterrz — a product studio from India.
New project
What do you want to build?
We build a small first version for you. You explore it, change it, then rebuild it yourself with a plan and an AI that tracks how close you are.
Your idea
Expense trackerSubtraction practiceTailoring shopInstagram clone
Where are you now?
Complete beginner
How do you want to build it?
HTML, CSS, JSReactSvelte
Goal
Get a job as a developer
Hours / week
10
Build my first version
Building · Pocket Ledger
Understand the idea
4 features now, 2 saved for later
9s
Write a first version
index.html · styles.css · app.js — 312 lines, no libraries
71s
Test and fix in a real browser
Opened it, filled in the form, reloaded. An empty amount still saved, so that is being fixed.
14s
writeapp.js: add, list and save expenses
testan empty amount still adds a row: sent back to fix
testtested again: no errors, 3 expenses saved
…
Pocket Ledger
Where the money goes each month.
Chai and snacks
Add
Groceries
Auto to college
Mobile recharge
This month
Change it
Show amounts in rupees
Done. One line changed in app.js: the formatter now uses ₹ and Indian grouping.
Let my friend see my expenses too
That needs a server and accounts. Your path gets there later, so it is saved for then.
Lock it in
Planning your pathYour path is ready
Turning Pocket Ledger into steps you can build one at a time.
Read the version you locked in
4 features built, 2 saved for later
Pick the concepts it needs
Group them into steps of a few hours
18 steps · ~45h · the same project all the way
Your path18 steps · ~45h
…9 more steps
Your buildSave & run
TTutorhints, not answers · knows your code and the step
StepPreviewsCheck this step
·
Final versionno picture on a server step; its checks show what done means
Pocket Ledger
Where the money goes each month.
Nothing here yet. Add your first expense.
September
₹ 4,320
Expenses
3
Biggest
Coffee
Amount
Enter an amount above 0.
Groceries
Add
GroceriesSep 31,240×
Bus passSep 2680×
CoffeeSep 12,400×
Server log
Press Save & run to start your server.
In the browser With a server Database, accounts
How it works
The AI writes the first version. You write the one that counts.
The AI's version is what you aim for, not what you hand in. You rebuild it yourself, and every step is checked against it.
Building · Pocket Ledger
Understand the idea
4 features now, 2 saved for later
9s
Write a first version
index.html · styles.css · app.js — 312 lines, no libraries
71s
Test and fix in a real browser
Opened it, filled in the form, reloaded. An empty amount still saved, so that is being fixed.
14s
writeapp.js: add, list and save expenses
testan empty amount still adds a row: sent back to fix
testtested again: no errors, 3 expenses saved
Pocket Ledger
Chai and snacks ₹ 120 Add
Groceries₹ 1,840
Auto to college₹ 260
Mobile recharge₹ 299
This month₹ 2,399
Change it
Show amounts in rupees
Done. One line changed in app.js: the formatter now uses ₹ and Indian grouping.
Let my friend see my expenses too
That needs a server and accounts. Your path gets there later, so it is saved for then.
3 changes · 1 saved for laterLock it in
Pocket Ledger18 steps · ~45h
Your version is the goal. Rebuild it step by step; the path keeps going.
In the browser
1 Show the Pocket Ledger page 1
2 Add and style an expense form 1
3 Read and check the expense form 1
4 Show and delete expenses 1
5 Save expenses and see the month summary 1
With a server
6 Set up and start your server 2
7 Build an API for your expenses 2
Database and accounts
8 Save expenses in MongoDB with a model 3
9 Sign up, log in, and keep expenses private 3
…9 more steps
2 of 18 done Last check: the form submits and clears itself. Next: read the amount and reject empty ones.
Your app's map Pocket Ledger
fetch /api/...
In the browser
Your server
Where data lives
A path, not a course
Every step ends with your app doing something new.
Your path is chosen from a graph of 128 concepts, each linked to the ones it needs first. It skips what you already know, keeps steps to a few hours each, and names every step after your own app. The same project carries on to a server, then a database and accounts.
Stuck? The tutor sits next to your code the whole time. It sees your files, points at your exact lines, and gives hints one at a time, from a nudge up to an example. It never edits your files.
1Step 3 · Read and check the expense form~3h
Lesson, written for Pocket Ledger
Right now the form accepts anything, even nothing. This step is about trusting your data: read the amount as a number, refuse what makes no sense, and tell the person why. Three ideas: Number(), the submit event, and returning early.
Tutor
It saves an empty expense when I click Add.
Look at app.js:14. What is
amount when the box is empty? Try Number("") in the console, then decide what your code should do with that.Check
· 1 of 2 · empty amount is rejected, negative is not yetOn every step
02
Lesson
Written for your app and your code, in plain English: why the step matters, the two or three ideas it needs, and what to do. No code to copy.
03
Tutor
Ask anything. It starts with a nudge, then the idea, then a small example, then the shape of the answer, and the full code only when you ask for it after trying. You type it yourself. It points at your exact lines and never edits your files.
04
Check
Press Check and the studio tests what you built: it opens your page in a real browser, or starts your server and calls it. You see what passed and what is still missing.
One project, all the way
Nothing is thrown away between stages.
Start in the browser, add a server, add a database and accounts. Server steps run in a private workspace of your own: Node or Go, a terminal, git, your own MongoDB, and a web address where your server answers.
- An editor with highlighting, formatting and search
- A terminal for your project's commands
- Checkpoints you can go back to
- Private to you, and walled off from the internet
1
In the browser
Zero setup. Your app runs in a live preview.
HTML, CSS and JavaScriptReactSvelte 5TypeScript, optionalSaving in the browser
2
With a server
Your own workspace with a terminal, git and a web address.
Node or GoHTTP and RESTGitCheckpoints
3
Database and accounts
A private MongoDB for your project, then sign up and log in.
MongoDBSign up and log inRun it like productionYour project's story, in a README
4
An agent inside
Coming soonPlanned, not built yet: your app learns to act on what you say, and you write the code that does it.
Your own toolsStreamingMemorySafety checksWhat a task costs
Then go deeper on the same code: The second climb AdvancedComing soondata structures, design patterns, and time and space complexity, measured on the app you built.
The agents path
Coming soonGive your app an agent. Then build the agent yourself.
Coming soon, and not built yet. This is the plan: once your app has a server and data, the next level puts an agent inside it. You say "add forty rupees for chai" and the expense appears. The AI writes that first version into your own code; you lock it in and rebuild it yourself.
No framework doing it for you. You will write the conversation, the reply as it streams in, your first tool and the loop that keeps going until the job is done, all by hand. Then the parts most tutorials skip: asking before it changes anything, recovering from errors, remembering across a reload, and standing up to data that tries to trick it.
The model will be the studio's: no API key to buy, nothing to install, and every call counted, so you will learn what a task costs instead of finding out on a bill.
A sketch of the agents path · Pocket Ledger Coming soon
Add 40 for chai
tool_calladd_expense(amount: 40, note: "chai")
tool_resultsaved as expense 12
usage2 calls · 1,870 tokens · 1 cache hit
Added ₹40 for chai. This month is ₹2,439.
Planned step 5 of 14 · Tools that change thingsComing soon
01
The loop
Planned: fourteen steps from a single AI call to an agent with memory and safety checks, each built in your own app.
02
Watch it think
Every action your agent takes, and every reply, will show up as cards, live, as it runs.
03
Your data is the test
Checks will grade what your agent actually did, not what it claimed: the expense was saved, it asked before changing anything, and it refused a trick hidden in the data.
04
Nothing gets out
Your workspace will reach the studio's model and nothing else, and the key will never leave the studio.
The second climb
AdvancedComing soonData structures, design patterns, and time and space complexity, on your own app.
The advanced climb, and worth taking once your app works. Your app works with ten items; does it work with twenty thousand? Coming soon, and not open yet. This is the plan: each concept taught on the app you built, measured on the code you wrote, and put to you by an interviewer.
59 concepts in five subjects, across the same three levels. You will pick the ones you came for — design patterns, complexity, data structures — or take the essentials and let the order look after itself.
Nothing here will be a puzzle. Your own app will be given more data, or asked for its next feature, until the simple version starts to hurt; the idea that fixes it will be shown on your own lines, and the same thing measured again after you change it. Data structures and complexity will be timed; a design pattern will be measured by what the next feature costs it, in the lines it changes; memory will be taught, not measured.
Any concept will be able to end in an interview: first about your own change, then, for most concepts, a classic interview problem reached through the feature you built. There will be no problem list to grind. Once you have finished a measured step, a mock interview on the whole project will open; you answer in writing, the way you would say it in the room, and keep the written summary.
Time and space complexityData structures and algorithmsDesign patternsWorking on a systemSaying it out loud
1Find one expense among 20,000Pocket Ledger
Measured before and after you changed it
Before 39.6 ms After too fast to time
So the studio says at least 198 times faster and no more: the new version was too fast for the clock to measure.
The problem behind the feature
Your lookup is a hash map now. Here is the interview version of it: given the expenses and a total, find the two that add up to it. Talk me through what it costs.
At the end
A mock interview on the whole project, answered in writing, and a written summary you keep.
Who it is for
Starting from zero
Never programmed. You get the plain HTML, CSS and JavaScript path, small steps, and a first win in the first session.
Looking for the first job
You know the basics but have not shipped a full app. Skip what you know; the path starts where your gaps are, and you finish able to explain every line in an interview.
Switching careers
Bring your own domain: a tool for the shop, the clinic, the classroom. The project is the portfolio.
Already writing code
You can already build things, and want what a serious interview digs into. Build your app here now; the second climb, coming soon, takes it apart for its data structures, patterns and complexity, measured on your own code.
Who is building it
Build to Learn Studio is a product of AppKrafterrz.
AppKrafterrz is a product studio from India, building its own products one domain at a time. Kalvi360, an AI-native operating system for schools, is live. Build to Learn Studio is the second, and it is in public beta.
No client work and no outsourcing: the people who plan the curriculum are the people who write the code, so what you tell us shapes what ships next.
appkrafterrz.comWhat it costs
Pay once to get in. Add projects when you want them.
One payment opens the studio and covers your first 6 projects. After that, buy a project whenever you want one. AI projects, with the agents path and its AI calls included, are coming soon: their prices are below, but they cannot be bought yet. No subscription, and nothing renews.
Free build
Your first build is on us.
One project, the phase in the browser, with the AI to build it. To start it, your bank puts a ₹1 hold on a card, to tell one person from a thousand sign-ups; the hold is released by your bank and never charged.
The AI comes as a budget with the project, and your project shows how much of it is used; it does not reset. The free build stops where the server phase begins, or when its budget is spent. Either way everything you made stays, and studio access carries on with the same project.
One more project
₹999 ₹3,999
1 more project, whenever you need it.
Bought from your account, any time.Two more projects
₹1,599 ₹6,999
2 more projects, whenever you need them.
Bought from your account, any time.With an agent inside
Coming soonOne AI project
₹1,599 ₹5,999
1 project with the agents path and 750 AI calls included.
Coming soon. Bought from your account when it opens.Two AI projects
₹2,499 ₹9,999
2 projects with the agents path, 750 AI calls each.
Coming soon. Bought from your account when it opens.Launch prices, in Indian rupees. Payments go through Razorpay.
What do you want to build?
An expense tracker, a habit board, a tool for your family's business, a clone of the app you use every day. Bring the idea; the curriculum follows.
₹6,999 once at launch, normally ₹19,999. Nothing to install, nothing renews.