The challenge is the point.

Your first paragraph

Inside the body, add an <h1> with your name and a <p> that describes what you want to build.

Add your metadata

Add a charset, a viewport meta tag and a descriptive <title> to the skeleton.

Build a mini outline

Create an h1 titled "My learning plan", an h2 titled "This month", and a paragraph with one important word wrapped in <strong>.

Link the stylesheet and the script

Add a link to a stylesheet and a script to this page so the browser loads the CSS and JavaScript files too.

Fix the heading outline

This page jumps from an h1 straight to an h3. Fix the levels so the outline steps down one at a time.

Make an article image responsive

This image sits below the first screen. Add width and height, a srcset with two sizes, a sizes value and lazy loading.

One labelled icon, one decorative icon

Draw one SVG that screen readers announce as "Search", and a second, purely decorative SVG they skip.

Make it accessible

Add a link to /tutorials with the text "Browse all tutorials", then add an image with descriptive alt text.

A study checklist

Create an ordered list with three steps: Learn, Practice, Get certified.

Add an email field

Add a labelled email input to the form, make it required and give it a helpful autocomplete value.

Replace the div soup

Rewrite the structure using header, nav, main and footer instead of divs.

Accessible profile image

Add a figure with a 320 by 320 image, useful alt text, lazy loading and a caption.

Write a page head

For a lesson called Accessible forms, add a title, description, canonical URL and Open Graph title and image.

Label the field and connect the hint

Add a visible label and connect the hint to the input so screen readers announce both.

Add a FAQ and a dialog

Write one details block and a dialog with Cancel and Confirm buttons that closes itself.

Add a project

Add a third project to the list: a link to /projects/budget with a one-line description using <strong> around the project name.

Style the callout

Write a class selector .callout that adds a light background, 16px padding and a 12px border radius.

Fix the overflowing card

A 400px card with 32px padding overflows its 400px container. Add the global border-box reset.

Create a fluid heading

Set h1 to a fluid size between 2rem and 3.5rem using clamp().

Lay out a badge row

Style a set of badges so they sit side by side but can still have a set width and height.

Size a card that stays readable

Style a card with comfortable padding and a maximum width so it does not stretch too wide.

Add a visible keyboard focus ring

Style buttons so keyboard users see a clear focus ring without affecting mouse clicks.

Make the title colour win

The title is stuck grey. Write a selector more specific than .title so the title turns blue.

Centre the hero content

Make .hero a flex container that centres its children both horizontally and vertically.

Responsive card grid

Create a grid that shows as many 240px-minimum columns as fit, with a 16px gap.

Make the layout adapt

Start with one column, then switch to two columns at 760px.

Pin a badge to the card corner

Place the badge in the top-right corner of the card without affecting the text flow.

Create a spacing scale

Define three spacing tokens and use them for the card padding and gap.

Add an error focus state

Give invalid inputs a red border, and a visible focus ring that stays red.

Accessible hover lift

Add a 180ms lift on hover, and remove it when the user prefers reduced motion.

Pulse once, then respect reduced motion

Animate a badge from scale 1 to 1.08 and back, and disable it for reduced-motion users.

Add a secondary button

Create a secondary variant that uses the surface, ink and line tokens with the same focus and disabled behaviour.

Build a greeting

Create const name and let points, add 10 to points, then log a template literal with both values.

Write a formatter

Write a function formatPrice(amount) that returns a string like "$12.50".

Calculate total minutes

Given the lessons array, use reduce to calculate total minutes across all lessons.

Price with a discount

Write a function totalWithTax(price, isMember) that adds 10% tax, then applies a 5% member discount only when isMember is true. Return the final amount rounded to 2 decimals.

First passing score

Write a function firstPassing(scores) that returns the first score that is 40 or more. Return null if none pass.

Parse a nested payload

Write a function readCity(jsonText) that parses the string and returns the city from inside the address object. Return "Unknown" if parsing fails.

Safe money total

Write a function totalCents(prices) that takes an array of dollar amounts and returns the total in whole cents, avoiding floating point errors.

Build a learner summary

Create a new object with fullName and best score, without changing the input objects.

Average with reduce

Return the average score using reduce, and 0 for an empty list.

Toggle a class

On button click, toggle the class "active" on #panel.

Load and render

Write an async function that fetches /api/lessons, checks the response and returns the parsed JSON.

Save and restore progress

Write saveProgress and loadProgress for a versioned progress object. Return a safe default when nothing is stored.

Guard the input

Throw a TypeError if email does not include "@", otherwise return the trimmed email.

Split a helper into a module

Write a format.js module exporting a named formatScore and a default formatName, then import both in app.js.

Test a clamp function

Write three tests for clamp(value, min, max): below the range, inside the range and above the range.

Add a restart

Write a restart() function that sets index and score back to 0, then re-renders.

Calculate a total

Given price = 24.5 and quantity = 3, print a sentence with the total using an f-string.

FizzBuzz, briefly

Print numbers 1–15. For multiples of 3 print "Fizz", for 5 print "Buzz", for both print "FizzBuzz".

Read and double a number

Ask the user for a number, convert it to a float, double it and print the result in a sentence.

Split the bill

Split a bill of 47.5 between 3 people and print how much each pays, rounded to 2 decimal places.

Fix the crash

The code below crashes. Fix it so it prints the first letter of the word in uppercase.

Count the digits

Count how many digit characters are in the sentence and print the total.

Filter the passing scores

Build a list of skill names with a score of 80 or more using a comprehension.

Count the lines

Read notes.txt and print how many non-empty lines it contains. Handle the missing-file case.

Build a URL slug

Turn the title into a slug: trim it, lowercase it and join the remaining words with hyphens.

Count word frequencies

Count how often each word appears in the sentence and print the resulting dictionary.

Sum the even squares

Print the sum of the squares of every even number from 1 to 20.

Add a score method

Extend the Learner class with add_score() and print the updated average for a learner with two scores.

Parse a JSON payload

Parse the JSON text, then print the learner and progress in the form "Ada: 7/12".

Test a word counter

Write two tests: one for an empty string, one for repeated words.

Write the setup commands

Create a virtual environment, install pytest 8.3.3 and save the exact versions.

Python FoundationsHard

Load, extend and save

Load the saved tracker, mark one more lesson complete and print the updated JSON.

List beginner courses

Return title and level from courses where level is "Beginner".

Find short lessons

Return titles of lessons under 12 minutes, ordered by minutes ascending.

Design a library_loans table that records which borrower took out which book and when. The books and borrowers tables already exist and each has a primary key column named id. Each loan should also have a unique id of its own.

Create a cheap products view

Create a view named cheap_products that shows only the id, name, and price of products that cost less than 20. The products table already has these columns.

Transfer money safely

Write a transaction that moves 50 from account id 1 to account id 2, so the money is never lost or duplicated. The accounts table has id and balance columns.

Find orders missing a status

Return the id and customer of every order that has no status, ordered by id. The orders table has id, customer, and status columns.

Course with lesson counts

List every course title with its number of lessons, including courses with zero.

Average lesson length

Return each course_slug and its average lesson minutes, only for courses with at least 3 lessons.

Total minutes with a zero fallback

Return every course title and its total lesson minutes, showing 0 when a course has no lessons.

Band the courses

For each course_slug, return the rounded average minutes and a band: Deep at 15 or more, Standard at 12 or more, otherwise Fast.

Above-average course totals

Use a CTE to total minutes per course, then return only courses above the average total.

Top two lessons per course

Return the two longest lessons in each course, with their rank inside the course.

Uppercase titles with length

Return each lesson title in uppercase and its character count, longest first.

Index for course and minutes

Create a composite index that speeds up filtering by course_slug and sorting by minutes.

Insert, update and roll back

In one transaction, insert a lesson called Indexes with 13 minutes, add 1 minute to it, then roll back.

Add average minutes and filter

Extend the report with average minutes per lesson and return only courses with at least two lessons.

Make a first commit

Stage README.md and create a commit with the message "Add project readme".

Write a useful message

Stage login.js and commit with a message that states the user-visible change.

Configure Git from scratch

Set your name to 'Ada Lovelace', your email to 'ada@example.com', make main the default branch, then create a repository in a folder called my-project.

Read the latest commit

Show a compact, graphical view of your history, then display the details of the most recent commit.

Ignore and untrack build output

Create a .gitignore that ignores the build folder and all .log files, then stop Git from tracking a build folder that was already committed.

Generate and test an SSH key

Generate an ed25519 SSH key with your email, add the private key to the SSH agent, then test the connection to GitHub.

Start a feature

Create and switch to a branch called feature/search, then push it with an upstream.

Undo the last commit, keep the work

Remove the most recent commit but keep its changes staged.

Park work and restore it

Stash the current changes with a message, switch to main, then come back and pop the stash.

Finish a merge safely

After resolving pricing.md, which commands complete the merge?

Rebase onto main

Update the origin remote, then replay feature/pricing on top of origin/main.

Start from origin/main

Create feature/search from origin/main and push it with an upstream.

Publish a release tag

Create an annotated tag v2.0.0 with a message and push it to origin.

Add a lint step

Extend the CI workflow so lint runs after dependencies are installed and before tests.

Inspect the current commit

Show the type and contents of the current HEAD object, then list its tree.

Git & GitHubHard

Write the release flow

For a bugfix branch fix/empty-cart, write the commands to push it, open a PR and tag v1.3.1 after merge.

Type a shopping list

Annotate a tuple that holds an item name and its quantity, then declare a readonly array of strings for the aisle names.

Annotate a helper

Write an arrow function total(price, tax) that returns a number. Make tax optional with a default value of 0.

Model a credential

Create a Credential type with id, holder and a readonly program, plus an optional score. Then build one valid object.

TypeScript FoundationsMedium

Handle a result union

Write a function that takes a Result union with ok and error variants and returns a message for each, using an exhaustive switch with a never helper.

Make the config strict

Add strict and noUncheckedIndexedAccess to a tsconfig. Explain in your own words why reading items[0] can now fail.

JSONOpen challenge

Type a score formatter

Write a function formatScore(name, score) that returns a string and rejects a string score at compile time.

Define a credential

Create a Credential interface with id, holder, program and an optional score. Then create one valid object.

TypeScript FoundationsMedium

Handle a loading state

Model a state union with loading, ready and error variants. Write a function that returns a user-facing label for each.

TypeScript FoundationsMedium

Build a typed picker

Write pick<T, K extends keyof T>(items: T[], key: K): T[K][] that extracts one property from each item.

Make the config strict

Add strict and noUncheckedIndexedAccess to a tsconfig. Explain which new error you would expect in a function that reads items[0].

JSONOpen challenge

Split a card into components

Split a LessonCard into a LessonTitle and a LessonFooter component, passing the title down as a prop and the onOpen callback through.

Build a Card wrapper

Create a Card component that accepts a title prop and children, and a Panel component that forwards all its props to a native div.

Add a reset action

Extend a quiz reducer with a reset action that returns the initial state, and a button that dispatches it.

Add a useTheme hook

Create a context with a null default, a provider that supplies a theme, and a useTheme hook that throws when the provider is missing.

Test a loading list

Write a test that renders a list that loads asynchronously, waits for an item to appear, and asserts it is visible.

Make a badge component

Create a Badge component that accepts children and a tone prop, and renders a styled span.

Toggle a bookmark

Add a saved boolean and a button that toggles it. Show "Saved" or "Save" based on state.

Cancel a fetch

Add an AbortController to a fetch effect and abort the request in the cleanup function.

Validate an email field

Add an email input with a label and a short error message shown when the value does not contain @.

Add a lesson route

Add a route /lessons/:slug that renders a Lesson component and a wildcard 404.

Load a JSON file safely

Write loadJson(path) that reads a file, parses it as JSON and returns an empty array when the file is missing. Re-throw other errors.

Redact a secret

Write a function that takes a config object with an apiKey field and returns a copy with apiKey replaced by "REDACTED".

Use a parameter in a query

Write findById(pool, id) that selects a row by id using a $1 placeholder and returns the first row or null.

Test a 404 path

Write a fake store whose findById always returns null, then assert that makeUserHandler returns a 404.

Close the server on a signal

Add a SIGTERM handler that calls server.close and exits with code 0 when the close callback fires.

Read a port safely

Read PORT from the environment and fall back to 3000. Print the value as a number.

Reject invalid notes

Return 400 when a note is shorter than three characters. Return 201 with an id for a valid note.

Add an API key guard

Write middleware that returns 401 when x-api-key does not match process.env.API_KEY, otherwise calls next.

Turn a rejection into a 500

Call an async function, catch a thrown error and respond with 500 and a generic error body.

Harden a session cookie

Set a session cookie with httpOnly, sameSite lax, secure in production and a one-hour max age.

C# FoundationsEasy

Classify a lesson length

Write a switch expression that returns short, medium or long from a lesson minutes value: short when 10 or less, medium when 20 or less, otherwise long.

Overload a formatting method

Write two overloads of a method named Describe: one taking a string title, and one taking a string title and an int minutes.

Implement a reportable item

Create an interface IPrintable with a string Render() method, then a record Lesson that implements it and returns its title.

Group lessons by course

Given a list of lessons with a CourseId, group them with GroupBy and return the count per course.

C# FoundationsEasy

Write a parameterised test

Write a [Theory] with two InlineData rows that verifies Add returns the expected sum.

C# FoundationsEasy

Format a nullable name

Write a method that returns a display name or "Learner" when the input is null or whitespace.

Protect a score

Create a Score class with a private setter and a method Add that never exceeds 100.

Filter and sort

Given a list of lessons with Minutes, keep those under 15 minutes and order them ascending.

Handle cancellation

Write an async method that loads a course and returns null when cancellation is requested.

Validate a course title

Return 400 with an INVALID_TITLE error when the title is empty; return 201 otherwise.

Average with integer division

Print the integer average of 20 divided by 3, then print the remainder of the same division on the next line.

Sum the first five numbers

Use a for loop to add the numbers 0 through 4 and print the total, which should be 10.

Write a maximum function

Write a prototype and a definition for a function max2 that returns the larger of two ints, then call it and print the result.

Measure and copy a title

Declare a string title, print its length with strlen, copy it into a second buffer with strcpy, and print the copy.

Fix the out-of-bounds loop

This loop reads one element past the end of the scores array. Fix the bound so it prints exactly the three scores without touching memory it does not own.

Print a lesson summary

Print "HTML: 8 lessons" using an int and a string.

Find the maximum

Write a function that returns the largest value in an int array plus its length.

Add a course printer

Define a Course struct and a function that prints title and minutes.

Allocate and free a score array

Allocate an array of five ints, check the allocation, write one value and free it.

Read a file safely

Open notes.txt for reading, print every line, and close the file. Handle a missing file.

C++ FoundationsEasy

Copy a lesson safely

Write a class Lesson with a std::string title member, a copy constructor that copies the title, and a copy assignment operator that copies the title into an existing object. Return *this from the assignment.

Move a vector

Write a class Holder that stores a std::vector<int>, with a move constructor and a move assignment operator that move the vector from the source. Mark both noexcept.

Make a polymorphic shape

Create an abstract base class Shape with a pure virtual method area() and a virtual destructor. Then create a derived Square that stores a double side and returns side * side from area().

Guard a resource with RAII

Write a class SafeFile that opens an std::ifstream in its constructor, throws std::runtime_error when the file does not open, and lets the destructor close the file automatically.

Register a test target

Write the CMake lines to create an executable target named lesson_tests from test/lesson_test.cpp, link Catch2::Catch2WithMain, and register it with add_test.

CMAKEOpen challenge

Encapsulate a score

Create a Score class with a private value and a method that clamps additions at 100.

Own a lesson safely

Create a unique_ptr to a Lesson with the title "RAII" and print the title.

Sort and search

Sort a vector of lesson titles and use std::find to check whether "Git" exists.

Clamp a value

Write a function template clamp(value, low, high) that constrains T to an integral type.

Configure a C++ target

Create a CMake executable named app from src/main.cpp and enable -Wall -Wextra.

CMAKEOpen challenge

Label a lesson by length

Write a main method that prints "short" when minutes is below 10, "medium" when it is below 20, and "long" otherwise.

Implement a printable lesson

Define an interface Printable with one method String display(), then make a VideoLesson class implement it and return its title plus its minutes.

Write a bounded max method

Write a generic static method largest that takes a List<T> and returns the largest element, where T is bounded to Comparable<T>.

Write your first assertion

Write a JUnit 5 test method that creates a Lesson with the title "Java" and asserts its title method returns "Java".

Add a runnable jar configuration

Given a minimal pom.xml, add a maven-jar-plugin configuration whose manifest sets the mainClass to com.edubyte.Main.

XMLOpen challenge

Validate a record

Write a record Lesson with title and minutes that rejects a negative minute value.

Count unique topics

Create a Set from a list containing duplicate topic names and print its size.

Translate an IOException

Catch an IOException while reading a path and throw an IllegalStateException with context.

Filter and map lessons

From a list of lessons, keep those under 15 minutes and collect their titles.

Add a GET endpoint

Create a controller with GET /api/health returning a map with ok = true.

Go FoundationsEasy

Classify a lesson length

Write a function classify(minutes int) string that returns "short" when minutes is under 10 and "long" otherwise.

Go FoundationsEasy

Look up a key safely

Write a function lookup(scores map[string]int, name string) (int, bool) that returns the score for name and whether it exists.

Satisfy a notifier

Define a type Message with a Text field and a method Notify() string that returns the text, so Message satisfies a Notifier interface with that single method.

Write a table test

Write a TestDouble that uses a table of cases to check Double(n) returns 2n for at least three inputs, reporting failures with t.Errorf.

Apply a timeout

Write a function run that creates a context with a 3-second timeout, calls work(ctx), and always calls the cancel function.

Go FoundationsEasy

Define a lesson

Create a Lesson struct with Title and Minutes, then print both fields.

Return a not-found error

Write Find(slug) that returns ErrNotFound when slug is empty.

Implement a store

Implement LessonStore with a MemoryStore that returns ErrNotFound for a missing slug.

Wait for workers

Start two goroutines that print their id, and use a WaitGroup to wait for both.

Add a health endpoint

Raise a score by shadowing

Declare an immutable score, then use shadowing to raise it by 10 and print the result.

Grade a lesson

Write a function grade(minutes: u32) -> char that returns A when minutes is 10 or less, B when 20 or less, and C otherwise.

Borrow the first three bytes

Write a function first_three(text: &str) -> &str that returns the first three bytes of a string.

Implement a Greet trait

Define a trait Greet with a method greet(&self) -> String, implement it for a struct Name, and write a function that accepts any Greet type.

Divide with a Result

Write a function divide(a: f64, b: f64) -> Result<f64, String> that returns an error message when b is zero.

Borrow a string

Write a function that returns the length of a &str without taking ownership.

Handle an Option

Write a function that returns a label from Option<&str>, using "Unknown" for None.

Read a file with ?

Write a function that reads notes.txt and returns Result<String, io::Error>.

Sum lesson minutes

Given a Vec of (title, minutes), sum the minutes and collect titles under 15 minutes.

Send a message between threads

Spawn a thread that sends "done" through an mpsc channel and print the received value.

Create your first role and database

Create a login role named app with password 'secret', then a database named myapp owned by app.

Link lessons to courses

Create a lessons table with an identity id, a course_id foreign key that cascades on delete, a title, and a minutes value that must be positive.

Make an atomic update

Start a transaction, insert a course and return its id, update its title, then commit.

Verify a restore

You just restored a database from a backup. Write a query that confirms the courses table is usable by counting its rows.

Find a missing index

A query filters lessons by course_id and its plan shows a Seq Scan. Write the index that turns it into an index scan.

Create a lessons table

Create lessons with an identity id, a course_slug foreign key, a slug, a title and positive minutes. Make course_slug + slug unique.

Add an expiry constraint

Create a certificates table with issued_at and expires_at and a constraint that expiry is after issue.

Count lessons per course

Join courses to lessons and return each course slug with its lesson count, including courses with zero lessons.

Index a lookup

Create an index on lessons(course_slug, minutes desc) and explain why it helps a filtered, ordered query.

Make an atomic publication change

Group a course update and an audit insert in one transaction.

Create a reading list

Switch to a database named library and insert a book document with title, pages and tags, then read it back with find.

Model one order

Insert an order document that embeds two line items, then reference a customer by id. Keep the embedded list bounded and small.

Move money atomically

Open a session and transfer 50 from account "ada" to account "grace" inside withTransaction so both updates commit or neither does.

Index a filtered sort

Create a compound index on published ascending and minutes descending, then confirm it is used by explaining a filtered and sorted query.

Verify a restore

After restoring into a scratch database, count the documents in the books collection and find one known title.

Model a small course

Insert a course document with slug, title, published and a bounded modules array.

Publish a lesson

Update the lesson with slug "queries" to published: true and increment its version by one.

Find short lessons

Find published lessons between 8 and 14 minutes and return only slug and title.

Summarize lessons by course

Aggregate published lessons by courseSlug and return lesson count and total minutes.

Index a filtered list

Create a compound index supporting published: true and sorting by minutes descending.

Run a web server in the background

Start an nginx:alpine container named web, map host port 8080 to container port 80, and run it detached. Then list the running containers.

Tag and push an image

Tag the node:22-alpine image as yourname/my-app:1.0 and push it to Docker Hub.

Write a cache-friendly Dockerfile

Write a Dockerfile that copies package*.json first, runs npm ci, copies the source, builds, and serves the built output from a runtime stage.

DOCKERFILEOpen challenge

Run a container that restarts itself

Run a web container with --restart unless-stopped so Docker brings it back after it exits.

Read why a container stopped

List all containers including stopped ones, then inspect one to read its exit code.

Run a throwaway command

Run node --version in a node:22-alpine container and remove it afterwards.

Run as a non-root user

Add a USER node line to a Node runtime stage and explain why it matters.

DOCKERFILEOpen challenge

Connect to a database by name

Run a postgres container named db on network edubyte, then run psql from another container using -h db.

Add a healthcheck

Add a pg_isready healthcheck to a Postgres service and make the app depend on it being healthy.

YAMLOpen challenge

Harden a run command

Run an app read-only with all capabilities dropped and no-new-privileges.