The Senior Path
You didn’t write this code. You own it now. Inherit a real production codebase — Arena Group, a nine-venue sports-booking platform — and do what senior engineers are actually hired to do: understand it, stabilise it, harden it, scale it, and lead the work on it.
✓ First 2 lessons free · no card needed · one plan unlocks every course
The course at a glance
Across twelve phases and roughly 6–8 months of weekend and evening work, students take over a real production codebase they did not write — Arena Group, a nine-venue sports-booking platform — and do what senior engineers are actually hired to do: understand it, stabilise it, harden it, scale it, and lead the work on it. Every junior course on the market teaches you to build from an empty folder. Almost nobody is hired to do that. Seniors inherit — and this program is built entirely around that truth.
The AI relationship changes with the seniority. In the junior path, the student directed one AI pair to write code. Here the student runs a small team of AI agents the way a senior runs a team: setting standards, decomposing work, delegating, reviewing critically, and signing their name to the outcome. The loop changes from Learn → Build → Break → Fix → Reflect to Assess → Decide → Delegate → Verify → Own.
How learning happens
Every chapter follows the same loop — taught in Phase 0 and run for the rest of the course. Two beats to learn, two beats to build. Most chapters take 30–60 minutes; the build chapter that closes each phase runs longer.
Learn
A short read plus an animated model of the idea. No syntax dumps — you learn what the thing is for.
Brief
Write the instruction in plain English. Precision of intent is the skill being trained here.
Review
Read what came back against a checklist. This is where engineers are actually made.
Tweak
Change one thing yourself, by hand, and watch it move. Ownership beats copy-paste.
What you need first
Junior Web AI Engineer (or equivalent)
You can build and deploy a Node + Express + SQL application, you’re fluent with Git, and you’re comfortable directing Claude Code.
Docker Fundamentals (or equivalent)
Required — the local stack runs on Docker Compose throughout the whole course.
The Senior Path — the Arena Group takeover
No new language to learn — everything stays JavaScript, graduating to TypeScript in Phase 4. Works standalone: the inherited codebase ships as the Phase 1 before-zip, so you don’t need to have built the original project yourself.
The portfolio
Everything built in this course is real, runnable, and shareable — and it compounds into one flagship artefact.
Map it, test it, refactor it
Read the inherited system, pin its behaviour with characterization tests and a CI gate, then pay down the 4,187-line bookings.js with metrics to prove the improvement.
TypeScript, data, security, contracts, async
Migrate to TypeScript live, tune the database to two million rows, run an OWASP security audit, version the API, and extract an async billing worker behind a queue.
Observe, ship, survive Grand Final, lead
Instrument the platform, ship without fear, run a live 40× traffic incident, then close as tech lead with an RFC, code reviews, and a promotion packet.
The capstone
There’s no separate capstone project here — the whole course is one continuous takeover. Arena Group, a nine-venue sports-booking platform, is inherited in Phase 1 and every later phase adds to the same system and the same dossier, until it survives Grand Final week at 40× normal traffic.
Arena Group
Map it, test it, refactor it
A system map, a risk register, characterization tests, a CI gate, and a 4,187-line module split into six focused files.
Typed, tuned, secured
A live TypeScript migration, a database tuned from 1.8s to 45ms on two million rows, and an OWASP audit with every fix linked to a PR.
Contracts, async, observable
A versioned /v2 API, an async billing worker behind a queue and Outbox, and full logs, metrics, and traces with real SLOs.
Deploy, survive, lead
A CI/CD pipeline with canaries and a rehearsed rollback, a live 40× Grand Final incident and postmortem, then an RFC and a promotion packet.
Concept coverage matrix
Every major concept, where it's introduced, and where it pays off.
The skill ladder
What you can honestly say after each stage. Each claim maps to something you've built, run, and can show on a screen.
Codebase Cartographer → Refactoring Lead
A system map, a risk register, and a 4,000-line module reduced to six files, live, with metrics proving it.
Migration Engineer → Security Auditor
A running JavaScript system migrated to TypeScript with zero feature freeze, and a fixed live OAuth vulnerability.
API Steward → Observability Engineer
A versioned, deprecation-managed API, a defended monolith-vs-microservices ADR, and SLOs the business signs off on.
Senior Web AI Engineer
A rehearsed two-minute rollback, a live 40×-load incident with a blameless postmortem, and a promotion packet where every claim links to evidence.
Time and pacing
Each chapter is roughly 2–3 hours of guided work plus 2–3 hours of practice. The steady cadence is one chapter per weekend or two evenings; phases wrap in 1–4 weeks depending on weight. The full program lands around 6–8 months — slightly faster than the junior path, because the student now works like a senior: delegating more, but reviewing harder.
Steady pace
One chapter per weekend or two evenings; phases wrap in 1–4 weeks depending on weight.
Typical chapter
2–3 hours of guided work plus 2–3 hours of practice.
Access
Every phase repo, before and after — including the Phase 1 before-zip if you’re starting fresh.
One subscription. Every course.
The Senior Path isn't sold on its own. A single MJ Tech Institute plan unlocks it alongside every other course we've shipped — 8 today, with more added over time — at no extra cost.
Everything, included
Subscribe once and every course unlocks — this one and every future release. No per-course purchases, ever.
Cancel any time
Monthly and annual plans cancel from My account whenever you like. Your progress is always saved.
Start free first
The first 2 lessons of The Senior Path cost nothing, no card required, before you choose a plan.
Finish with a Senior Dossier with your name on it
Phase 0 is free and takes about an hour. If it doesn't click, you've lost nothing.
Start the course today