MasteringBackend
BACKEND PROJECT

DocuChat: AI-Powered Document Q&A System

Build a production-grade AI-powered document Q&A system where users upload documents, ask questions, and get answers with citations — powered by RAG (Retrieval-Augmented Generation), vector search, and OpenAI.

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advanced 6 weeks 30 tasks 300 pts
DocuChat: AI-Powered Document Q&A System

Project Description

DocuChat is an AI backend project that teaches you how to build the kind of system behind products like Notion AI and ChatGPT with file uploads.Users upload documents (PDF or text). The system chunks the text, generates vector embeddings, and stores them in PostgreSQL with pgvector. When a user asks a question, the system searches for the most relevant chunks using semantic similarity, assembles them as context, and

What you'll learn

  • Node.js

  • Python

  • TypeScript

  • API Development

  • AI/ML Integration

  • Database Design

Project tasks

01

Project Setup, Database & Authentication

Set up the DocuChat project foundation. Configure the Express server with TypeScript and a layered architecture (controller → service → repository). Design the Prisma database schema with SQLite for development and PostgreSQL for production. Implement JWT authentication with refresh token rotation,

02

RBAC, Background Jobs & External Integrations

Implement role-based access control using junction tables (not arrays) for role-permission mappings. Build background job processing with BullMQ and Redis for async work like document processing. Integrate external APIs with Axios interceptors, retry logic with exponential backoff, and circuit break

03

Caching, Rate Limiting, Security & Observability

Make DocuChat production-ready. Add Redis caching with cache-aside pattern and proper invalidation strategies. Implement per-user rate limiting with token bucket and sliding window algorithms, tiered by user role. Harden security with Helmet, CORS, input sanitization, and prompt injection defenses.

04

Vector Database, Document Processing & RAG Pipeline

Build the core AI pipeline that makes DocuChat what it is. Set up pgvector for vector storage with HNSW indexes. Upload documents (PDF, TXT) with multer, extract text, chunk intelligently, and generate embeddings with OpenAI's text-embedding-3-small. Build the RAG pipeline: embed user questions, ret

05

HITL Systems, Agent Patterns, Memory & AI Testing

Design AI systems that are safe and reliable in production. Build a human-in-the-loop review system with confidence scoring that routes low-confidence answers to a review queue. Implement agent autonomy guardrails — action whitelists, budget caps, kill switches, and supervisor patterns. Build ReAct

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DocuChat: AI-Powered Document Q&A System

Date

Apr 2026

Instructor

MB Team

Certificate ID

MB-B9DH39

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Project Overview

6
Weeks
30
Tasks
300
Points
Difficulty
advanced
Builders
2

Technologies

Node.jsTypeScriptExpressPythonPrismaPostgreSQLpgvectorRedisBullMQOpenAI APIJWT

Prerequisites

  • Solid knowledge of JavaScript and TypeScript.
  • Solid knowledge of Python.
  • Basic understanding of REST API design.
  • Familiarity with relational databases (SQL).
  • A free or paid OpenAI API key.

Real Students.
Real Success Stories.

Lyle Christine
Lyle ChristineA Happy Student from Scotland

"I truly appreciate the high-quality material in this course. The structured lessons, hands-on projects, and clear explanations make learning a great experience. I look forward to future additions and updates! Thanks for your polite and friendly attitude."

Daniel Tinivella
Daniel TinivellaSoftware Engineer, Globant

"The practical examples and hands-on exercises were particularly beneficial. They not only reinforced the theoretical concepts but also allowed me to apply them in real-world scenarios. The inclusion of best practices and common pitfalls added a practical dimension to the learning process."

Eshan Shafeeq
Eshan ShafeeqBlockchain & Web3 Engineer, Cake Defi

"The course is an excellent resource for beginners. Your explanations of the basics are clear, making it easy for newcomers to grasp. I particularly enjoyed the task management application; it's a practical example that helps solidify the concepts."