Learning path

JavaScript Developer Roadmap

What to learn, in order, to work as a JavaScript developer: the language and TypeScript, the command line, Git and SQL, then the data structures and algorithms interviews test, and finally code a team can maintain. The same foundation serves frontend, backend and full-stack work. Free, hands-on, in your browser.

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503,064+ codders enrolled across these courses

651 lessons577 challenges2,785 quiz questions

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The JavaScript developer roadmap, step by step

17 courses7 sections651 lessons577 challenges2,785 quiz questions

Each step is made of existing Coddy courses, and every Start button opens them in JavaScript. Take the steps in order, or start with the one you are missing; progress is saved per course.

1
Step 1
JavaScript, then TypeScriptDedicated page
Start this stepStartFour sections. Fundamentals covers variables, strict and loose equality, type coercion, functions and arrow functions, and arrays; Logic & Flow covers strings, JSON and objects, the spread operator, sets, and the array methods map, filter, reduce and sort; Introduction To TypeScript covers core types, tuples, unions, interfaces, enums, generics and type guards; Object Oriented Programming covers this, modules, classes, private fields, inheritance and composition. Learn it deeply: every framework you meet later is JavaScript underneath, and its loose rules, == beside === and silent type conversion, are traps only until you know them.Start Dedicated page
4 sections, in order
271 lessons288 challenges1,457 questions
2
Step 2
Linux and the command lineDedicated page
Start this stepStartPaths and files, wildcards, grep, pipes and redirection, permissions, environment variables and shell scripts. JavaScript tooling lives in the terminal: npm install, npx, dev servers, builds and test runners are commands, the scripts in package.json are shell commands, and secrets reach a Node.js app as environment variables through process.env.Start Dedicated page82 lessons68 challenges440 questions
3
Step 3
Git and version controlDedicated page
Start this stepStartStaging, commits, .gitignore, branches, merges and conflicts, undoing mistakes and remotes. In a JavaScript project node_modules/ is ignored from the first commit and package-lock.json is committed, and a busy lockfile is where parallel branches often conflict. Hosts such as Vercel and Netlify deploy on every push, so on many web teams a merge to main is a release.Start Dedicated page58 lessons46 challenges370 questions
4
Step 4
SQL fundamentalsDedicated page
Start this stepStartFiltering, sorting, joins, grouping, aggregates, subqueries, WITH clauses and window functions, on real tables. Full-stack JavaScript means a database behind the API, often PostgreSQL or MySQL, reached through an ORM or query builder such as Prisma; reading the SQL it sends is how you find out why an endpoint is slow.Start Dedicated page72 lessons72 challenges360 questions
5
Step 5
Data structures, built by hand
Start this stepStartStack, queue, linked list, binary tree and hash table, each built from scratch in JavaScript and then used on problems. They are the shapes JavaScript applications already run on: undo history is a stack, the event loop works through a queue, and a nested menu or a JSON document is a tree.Start
5 courses, in order
66 lessons34 challenges
6
Step 6
Algorithms and recursive thinking
Start this stepStartRecursion challenges, then bubble, selection, insertion, merge and quick sort in JavaScript, each sort paired with Coddy's algorithm visualizer. Recursion is everyday JavaScript, walking a nested object or a component tree, and it has a ceiling: go too deep and V8, the engine in Chrome and Node.js, throws RangeError: Maximum call stack size exceeded. This step teaches you to see that coming.Start
6 courses, in order
62 lessons37 challenges158 questions
7
Step 7
Code other people can read
Start this stepStartAn object-oriented project built end to end and a bank of coding problems, both in JavaScript. Prettier settles formatting and ESLint flags some mistakes; naming, function size and where responsibilities live are left to you, and they are what reviewers comment on.Start
2 courses, in order
1. User Class - OOP Project8 lessons1 challenges
2. Coding Problems32 lessons31 challenges
40 lessons32 challenges

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1const greeting = "Hello, Coddy!"

2function sayHi(name) {

3 return greeting + " " + name

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"Alex"

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Read, listen, test yourself, ask the AI, or look up anything you've already covered. Every lesson meets you where you are.

Intro to Variables

Audio

A variable is a named container that stores a value you can reference later in your program.

In Python, you create one by writing the name, an equals sign, then the value you want to store.

The value can change over time - reassigning the name simply points it to a new value.

1xSarah

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Certificate of Completion

This certifies thatJohn Doehas successfully completed

Python Fundamentals

DateJan 2026

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Why follow this JavaScript roadmap on Coddy

One language across the web. JavaScript runs in every browser, and with Node.js it also runs servers, build tools and scripts, so frontend, backend and full-stack jobs all start from the foundation this roadmap builds before they split.
TypeScript inside the first step. The JavaScript course has a full TypeScript section, from core types and unions to interfaces, enums and generics, so the typed JavaScript many professional teams write is part of the language you learn, not a surprise at your first job.
Interview practice in JavaScript. The data structures, the recursion challenges and the five sorts are all taught in JavaScript, so you rehearse interviews in the language you will actually be asked to use.
Graded, hinted, nothing to install. Each lesson closes on a JavaScript challenge that test cases grade, and Bugsy, the AI tutor, points at what is wrong without writing the fix. Most courses end with a free certificate, and there is no Node.js or editor to set up: it all runs in the browser.

Frequently asked questions about becoming a JavaScript developer

How long does it take to become a JavaScript developer?

Six to twelve months at about an hour a day is a fair range from zero to a junior interview. On this roadmap the JavaScript course, TypeScript section included, takes eight to ten weeks; the command line, Git and SQL about a month together; the data structures and sorting steps two more. Then comes the specialty, a framework such as React or a Node.js backend, built into one or two projects you can show.

Is JavaScript a good first language for a software engineer?

Yes, with one caution. It runs everywhere, shows results in a browser at once and leads directly to paid work on the web. The caution is that JavaScript forgives mistakes other languages reject: == converts types before comparing, and a missing property is undefined rather than an error. That is why this roadmap's first step includes TypeScript, and why the data structures steps make you build each structure yourself.

What does a JavaScript developer need to know besides JavaScript?

The command line, Git and SQL, which this roadmap covers, then the platform you write for, which it does not: HTML, CSS, the DOM and a framework such as React in the browser, or Node.js, npm and HTTP on the server. Coddy's Frontend path covers the browser side, React included, and picks up where this page leaves off.

Should I learn TypeScript or JavaScript first?

JavaScript first, and TypeScript soon after. TypeScript is JavaScript with types added, and its errors only make sense once you know what the JavaScript underneath does. The JavaScript course orders it that way: two sections of plain JavaScript, then the TypeScript section, then object-oriented programming.

Which course on this roadmap is not taught in JavaScript?

One: clean code is taught in Python only so far, so it is listed after the steps rather than in step seven. Its subject, naming, function size and structure, reads the same in any language, and linters such as ESLint catch only a slice of it. Every step, the object-oriented project and the coding problems included, is in JavaScript.

Is this JavaScript roadmap free?

Yes. Every course on it is free: the lessons, the editor and the Linux terminal in your browser, the test-graded challenges, Bugsy's hints and the certificates. Pro removes the daily energy limit and adds unlimited AI help, and nothing on this roadmap requires it.

Other learning paths

The same courses, arranged for a different role. Progress carries over: a course finished on one path counts on every path that includes it.

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