Your First 90 Days roadmap

What you will learn

1. 1. Onboarding & Your First 90 Days

   Onboard well, read an unfamiliar codebase, ask for help at the right time and turn feedback into a growth plan.

   • Onboarding & First Weeks — Junior Career & Interviews · Onboarding & First Weeks
   • Reading an Unfamiliar Codebase — Junior Career & Interviews · Reading an Unfamiliar Codebase
   • Asking for Help & Learning on the Job — Junior Career & Interviews · Asking for Help & Learning on the Job
   • Feedback & Growth Plan — Junior Career & Interviews · Feedback & Growth Plan

2. 2. Pull Requests for Juniors

   Open small, clear pull requests, take review feedback well and review your teammates' code with confidence.

   • Small, Clear Pull Requests — Junior Career & Interviews · Small, Clear Pull Requests
   • Receiving Review Feedback — Junior Career & Interviews · Receiving Review Feedback
   • Reviewing as a Junior — Junior Career & Interviews · Reviewing as a Junior

3. 3. Git Collaboration

   Fetch, pull and push with remotes, and team workflows built on pull requests.

   • Fetch, Pull & Push — Git · Fetch, Pull & Push
   • Workflows, Pull Requests & Code Review — Git · Workflows, Pull Requests & Code Review

4. 4. Testing Essentials

   Unit tests with Arrange-Act-Assert, then integration and end-to-end tests.

   • Unit Testing & AAA — Testing & Quality · Unit Testing & AAA
   • Integration & E2E Testing — Testing & Quality · Integration & E2E Testing

5. 5. TDD Fundamentals

   Learn the red-green-refactor cycle, write tests first in small steps and practise it on classic katas.

   • Red, Green, Refactor — Testing & Quality · Red, Green, Refactor
   • Test-First Design — Testing & Quality · Test-First Design
   • TDD Kata Walkthroughs — Testing & Quality · TDD Kata Walkthroughs

6. 6. TDD in Practice

   Use TDD outside-in with test doubles, fix bugs and refactor safely, tame legacy code and avoid the common pitfalls.

   • Outside-In TDD & Test Doubles — Testing & Quality · Outside-In TDD & Test Doubles
   • Bug Fixes & Safe Refactoring with TDD — Testing & Quality · Bug Fixes & Safe Refactoring with TDD
   • Legacy Code, Seams & Characterization Tests — Testing & Quality · Legacy Code, Seams & Characterization Tests
   • TDD Pitfalls & Design Feedback — Testing & Quality · TDD Pitfalls & Design Feedback

7. 7. Code Review & MentoringOptional

   Give and receive useful code reviews and help teammates grow.

   • Code Review — Engineering Leadership · Code Review
   • Mentoring — Engineering Leadership · Mentoring

8. 8. Test Doubles & Test DesignOptional

   Isolate code with mocks, stubs and fakes, and design boundary, negative and regression tests.

   • Mocks, Stubs & Fakes — Testing & Quality · Mocks, Stubs & Fakes
   • Boundary, Negative & Regression Testing — Testing & Quality · Boundary, Negative & Regression Testing

9. 9. Design PrinciplesOptional

   SOLID, coupling and cohesion, and DRY, KISS and YAGNI.

   • SOLID — Clean Code & Software Design · SOLID
   • Coupling, Cohesion & Composition — Clean Code & Software Design · Coupling, Cohesion & Composition
   • DRY, KISS & YAGNI — Clean Code & Software Design · DRY, KISS & YAGNI

10. 10. SOLID in Practice

    Apply the five SOLID principles to real code: spot violations, refactor them and explain the trade-offs in an interview.

    • Single Responsibility & Open/Closed — Clean Code & Software Design · Single Responsibility & Open/Closed
    • Liskov Substitution & Interface Segregation — Clean Code & Software Design · Liskov Substitution & Interface Segregation
    • Dependency Inversion & Injection — Clean Code & Software Design · Dependency Inversion & Injection
    • Spotting SOLID Violations — Clean Code & Software Design · Spotting SOLID Violations

11. 11. Incidents & ReliabilityOptional

    Handle incidents calmly, learn from them and build reliability practices into the team.

    • Incident Handling — Engineering Leadership · Incident Handling
    • Reliability Practices — Engineering Leadership · Reliability Practices