🐍 Backend & AI Systems Engineering: 90-Day Master Roadmap

A rigorous, production-grade 90-day learning, coding, revision, and interview blueprint to evolve from Python core to an Enterprise Python Backend & AI Systems Engineer.

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📌 Repository Architecture

Every single day follows a strictly standardized 7-file contract:

Day-XX-[Topic-Name]/
├── README.md         # 15-Point Deep-Dive Notes
├── example_01.py     # Core Concept / Working Code (Explaining "WHY")
├── example_02.py     # Production-grade Pattern / Real-world Use
├── mistakes.md       # 5-10 Common Pitfalls & Antipatterns
├── exercises.md      # 3-5 Practical Problems to solve
├── interview.md      # Top 5-10 Interview Questions with Answers
└── revision.md       # Quick 5-Minute Bullet Revision

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🗺️ 90-Day Phase Roadmap

Phase	Days	Focus Area	Capstone Project / Deliverable
Phase 1	Days 01–15	Python Core, Internals, OOP & Concurrency	CLI Utilities & Async Processing Engine
Phase 2	Days 16–30	Practical Backend DSA Patterns	In-Memory LRU Cache & Rate Limiting Engine
Phase 3	Days 31–45	Web Standards, Django & DRF Production	Project 1: Multi-Tenant DRF SaaS API
Phase 4	Days 46–60	Databases (SQL, Postgres, SQLAlchemy) & FastAPI	Project 2: High-Throughput Async FastAPI Platform
Phase 5	Days 61–75	DevOps, Docker, AWS & High-Scale System Design	Project 3: Microservices Event-Driven Backend
Phase 6	Days 76–90	ML Engineering, LLMs, RAG, Agents & Interviews	Project 4: Enterprise Multimodal RAG & AI Agent Backend

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🚀 Daily Routine & Contribution SOP

1. Check Out Topic: Review today's curriculum in ROADMAP-90-DAYS.md.
2. Read & Code: Study the daily README.md and execute example_01.py & example_02.py.
3. Solve Exercises: Work through exercises.md and test edge cases.
4. Git Commit & Push:

   git add 01-Python-Foundation/Day-01-Python-Environment/
   git commit -m "feat(day-01): python environment, memory model & production validator"
   git push origin main

5. Update Tracker: Mark the day complete in PROGRESS.md.

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📂 Quick Directory Links

• 🚀 20 Software Engineering Topics for the AI Era (Master Engineering Pillars & Phased Plan)
• 🧠 AI Backend Core Skills Theory Guide (Daily Theory, Architectures & Comparisons)
• 01-Python-Foundation
• 02-DSA-Essentials
• 03-Django-and-DRF
• 04-SQL-Postgres-FastAPI
• 05-DevOps-System-Design
• 06-ML-and-AI-Systems
• Progress Tracker
• Complete 90-Day Syllabus