Engineering classes that respect your time.
Frontend, backend, systems, infra, mobile, security, pick the role or topic and Octo writes the class around the parts you actually have to ship.
Data Structures & Algorithms
The foundation every great engineer leans on. Learn data structures and algorithms from first principles, so you stop memorizing patterns and actually understand them.
Coding Interview Foundations
Stop grinding random LeetCode problems. Learn the small set of patterns behind almost every coding interview, so the questions start to look familiar instead of impossible.
Python From Scratch
The fastest way from total beginner to writing real Python. Build the fundamentals from scratch and finish with a small project that actually runs, no copy-paste required.
Java for CS Students
The Java your CS course assumes you already know. Learn the language the way college actually teaches it, so lectures and assignments stop feeling like a foreign language.
C++ for CS Students
The C++ the rest of your CS curriculum depends on. Learn pointers, memory, and the STL clearly, so OS, compilers, and interviews stop being a wall.
Object-Oriented Programming
The OOP explanation that finally clicks. Learn classes, inheritance, and design principles by building real examples, so you understand why OOP exists, not just how it works.
Operating Systems Fundamentals
Open up the black box your code runs inside. Learn how processes, memory, and threads actually work, so you stop guessing why programs hang, leak, or crash.
Computer Architecture
What actually happens when your code runs. Go from transistors to cache to assembly, so the machine stops being magic and starts making sense.
Discrete Math for CS
The math your algorithms course assumes you already know. Learn logic, sets, and graphs in plain language, so proofs and analysis stop feeling like another language.
Git & Version Control
Stop being afraid of Git. Learn how it really works under the hood, so commits, rebases, and merge conflicts stop feeling like a coin flip.
Senior Frontend Engineering
The skills that separate senior frontend engineers from mid-level ones. Learn the patterns, trade-offs, and architectural judgment that get you the title, the trust, and the offers.
React Deep Dive
Move from shipping React apps to understanding why React works. Master concurrent rendering, server components, suspense, and the patterns shaping every serious React codebase.
Next.js Mastery
You moved to App Router and half your habits no longer apply. Master server components, server actions, and edge runtime, so Next.js stops surprising you in production.
TypeScript for Real Codebases
Your TypeScript types break the moment a real codebase touches them. Learn generics, conditional types, and narrowing well enough that types help you instead of fighting you.
Frontend Performance
Your Lighthouse score is bad and you do not know which fix actually matters. Learn Core Web Vitals, INP, hydration, and RUM, so you can move the numbers that decide rankings and revenue.
Design Systems Engineering
Your team has built three component libraries and nobody uses any of them. Learn the tokens, primitives, and headless UI patterns that get a design system actually adopted.
Web Accessibility
Accessibility feels like a checklist nobody has time for, until a complaint lands. Learn what a real, accessible product looks like, so a11y stops being a fear and starts being a habit.
Backend Engineering Foundations
You can wire up an API and you have only a vague sense of how the rest works. Build a real mental model of a backend service end to end, so the work stops feeling like guesswork.
Senior Backend Engineering
You ship features and the senior backend engineers ship systems. Learn concurrency, consistency, idempotency, and observability well enough that you start being one of them.
API Design
You designed an API and now you are stuck with it for three years. Learn the REST, GraphQL, and RPC trade-offs that decide which APIs age well and which become technical debt.
Event-Driven Architecture
Your team is moving to events and the failure modes are biting. Learn queues, streams, and sagas, plus the patterns that keep event-driven systems sane under real load.
Caching Strategies
Your latency is bad and your cloud bill is worse. Learn the CDN, application, and database caching layers that move both numbers, plus the invalidation traps that cause outages.
Background Jobs & Workers
Your background jobs run twice, fail silently, or stop entirely on weekends. Learn the queue, scheduler, and retry patterns that get async work right the first time.
System Design Fundamentals
You can read a system diagram and you cannot draw one yet. Learn the load balancers, caches, databases, and queues piece by piece, so the building blocks finally make sense.
System Design Interview Prep
You freeze when the interviewer says design Twitter. Learn the structure, clarifying questions, and out-loud reasoning that turns the system design loop from a guessing game into a script.
Scaling Real Systems
Tutorials show monoliths and case studies show finished diagrams. Walk through the actual jumps from monolith to multi-region, so you understand which trade-offs decided each step.
Low-Latency Systems
You work in a place where ten milliseconds is revenue. Learn the caching, async, and architectural choices that move tail latency, not just average latency.
Multi-Tenant Architecture
Your SaaS works fine until a noisy customer takes everyone else down. Learn the isolation models and tenancy patterns that real SaaS companies use to keep tenants apart.
Distributed Systems Foundations
You read distributed systems papers and the words feel slippery. Learn CAP, time, ordering, and consensus from the ground up, so the mental models behind every distributed problem click.
Consistency Models Explained
Your database promises consistency and your team argues about what that means. Learn linearizability, sequential, causal, and eventual clearly, so you pick the model your product actually needs.
Paxos & Raft
You can quote the Raft paper and you cannot quite implement it. Build Paxos and Raft up in code and debug them, so consensus stops being the algorithm everyone pretends to understand.
Replication & Partitioning
Your data outgrew one box and now decisions get expensive. Learn the master-slave, leaderless, and sharding trade-offs, so you pick a design that survives the next order of magnitude.
Databases for Engineers
You write CRUD all day and the rest of the database feels like trivia. Learn indexes, transactions, joins, and normalization for real, so the database stops being something you fear.
Postgres Deep Dive
You use Postgres every day and your knowledge stops at SELECT. Go deep on MVCC, query planning, partitioning, and extensions, so Postgres becomes leverage instead of a black box.
Database Internals
Your queries are slow and the docs assume you know what an LSM tree is. Learn B-trees, LSM trees, and write-ahead logs, so the storage layer stops being magic underneath your code.
Query Optimization
Your slowest query is taking down production at 9am. Learn to read EXPLAIN, design indexes that work, and rewrite the queries that crush your database before they crush you.
Schema Design That Scales
You designed a schema two years ago and now every migration is a war. Learn the normalization, denormalization, and evolution patterns that produce schemas you can actually live with.
QA Engineering Foundations
You are doing manual testing and your team wants automation yesterday. Learn the modern QA toolkit step by step, so the move from clicker to engineer stops feeling so big.
Playwright Mastery
Your Playwright suite is flaky and your CI runs are slow. Learn the selectors, fixtures, and parallelism patterns that turn brittle tests into a suite the team trusts.
API Testing Deep Dive
Your API tests pass and your customers still find regressions. Learn the REST, GraphQL, and contract testing patterns that actually catch the bugs that get to production.
Mobile App Testing
Your app passes on the simulator and crashes on a Pixel 4a in Brazil. Learn the device, emulator, and review-process testing that keeps your app from getting yanked from the store.
Accessibility Testing
Your team treats a11y as a checklist, until a screen-reader user files a ticket. Learn accessibility as a real testing discipline, automated, manual, and assistive tech end to end.
Test Strategy & Leadership
Running QA at scale is more politics than testing. Learn risk-based test plans, hiring, and managing flake across many teams, so you can lead a QA org instead of fighting fires.
AI Test Automation
Every vendor says AI will write your tests for you and most of those tests are junk. Learn where AI genuinely helps generate, prioritize, and triage tests, and where it gets in the way.
DevOps Fundamentals
You ship code and the deploy is still someone else's problem. Move from works-on-my-machine to a real CI/CD pipeline you own and understand, so deployment stops being scary.
Kubernetes in Production
Your cluster works on Friday and pages you on Sunday. Go past the tutorial and learn the operational concerns, networking, autoscaling, and upgrades that actually bite at scale.
Terraform & Infrastructure as Code
Your Terraform state file is one bad apply away from a disaster. Learn modules, state, drift, and multi-account patterns, so IaC scales to your real org instead of your one repo.
Observability & SRE
Your dashboards have everything and tell you nothing during an incident. Learn logs, metrics, traces, and SLOs, so your system becomes legible the moment something goes wrong.
CI/CD Pipelines
Your CI takes thirty minutes and everyone learned to wait. Learn the pipeline patterns that are fast, safe, and stop being the bottleneck on every PR.
Cloud Cost Optimization
Finance is asking why the AWS bill went up again and you do not have a great answer. Learn the FinOps patterns engineers can actually run, so you move the bill without slowing the team.
Platform Engineering
Your team keeps building the same plumbing and your platform team is overwhelmed. Learn what an internal developer platform actually is, and how to build one developers will use.
AWS Solutions Architect Associate
Pass the SAA-C03 without memorizing every AWS service name. Learn the architecture patterns the exam actually tests, so the questions stop feeling like trivia and start feeling like decisions.
AWS Developer Associate
Pass the AWS Developer Associate exam and come out actually able to build on AWS. Learn the services and patterns the exam tests, weighted to where you are weakest.
Google Cloud Associate Cloud Engineer
You want the ACE cert without sitting through a 40-hour generic course. Learn the GCP fundamentals the exam tests, mapped to what you already know and what you do not.
Google Cloud Professional Cloud Architect
The Pro Architect exam is harder than the ACE and the case studies are where most people lose points. Learn the design trade-offs, case-study reasoning, and the questions that decide your score.
Azure Fundamentals (AZ-900)
Your boss wants the cert and you have never used Azure. Learn cloud concepts and Azure services from zero, so the AZ-900 becomes a one-week prep, not a six-week ordeal.
Azure Administrator (AZ-104)
Pass the AZ-104 against the current blueprint, not last year's. Learn identity, compute, storage, and networking the way the exam asks, so you walk in knowing what to expect.
Multi-Cloud Architecture
Your CTO wants multi-cloud and the team is not sure why. Learn when multi-cloud genuinely helps, when it just adds cost, and what a good multi-cloud design actually looks like.
iOS Development with Swift
You came up on UIKit and SwiftUI keeps changing under you. Learn the modern iOS stack, SwiftUI, Combine, and concurrency, so you ship native apps you are proud to put your name on.
Android Development with Kotlin
You learned Android in the XML era and Compose moves fast. Master Jetpack Compose, coroutines, and the modern Android stack, so your apps stop feeling stuck in 2018.
React Native in Production
Half your team wants React Native and the other half thinks it is a toy. Learn when RN is genuinely the right call, and how to ship apps that do not feel like web wrappers.
Flutter Fundamentals
You know web or native and Flutter is starting to land contracts. Learn Dart, widgets, and state cleanly, so you can pick up Flutter without feeling like a beginner again.
Mobile App Performance
Your app launches in three seconds and your reviews mention it. Learn to fix cold starts, memory, battery, and jank, so the app store ratings climb back where they belong.
Security for Engineers
Security tickets land on your desk and you wing the response. Learn threat modeling, OWASP, and crypto basics, so security stops being something you outsource to a checklist.
CISSP Exam Prep
CISSP is a marathon and most prep books are 1,000 pages of trivia. Learn the eight domains weighted to your gaps and the current blueprint, so you walk in ready, not buried.
CompTIA Security+
You need Sec+ for the role and you do not have weeks to grind videos. Learn the current SY0 blueprint mapped to your background, so you pass without memorizing acronyms you will never use.
Application Security
You ship code daily and your AppSec team is two people for the whole company. Learn auth, authz, secrets, and supply-chain security, so you stop shipping the easy bugs.
Cloud Security
Your cloud account has 200 IAM roles and nobody knows what most of them do. Learn IAM, network, data, and posture work that turns chaos into a security model you can defend.
Offensive Security Foundations
You are on the blue team and you keep getting outflanked by people who think like attackers. Learn the red team mindset in a practical, ethical, and structured way, so you stop being surprised.
Solidity Fundamentals
Solidity looks like JavaScript and behaves like a minefield. Learn to write safe contracts on EVM chains, so you avoid the foot-guns that have drained protocols for nine figures.
Smart Contract Security
You write contracts and the audit comes back with twelve criticals. Learn the bug classes that have cost protocols millions, so you find them before an auditor or attacker does.
Web3 Product Engineering
Web3 demos look easy and the production reality is wallets, signing, and indexing pain. Learn the off-chain services and patterns that ship real Web3 products users can actually use.