Code Reviewer Chatbot

A web-based AI chatbot that reviews code snippets for bugs, security issues, performance, and style. Supports multi-turn conversation, persistent chat history per user, and account-based session isolation.

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Team

Student	Name	Responsibility
A	Iulian	Frontend (React), Express server bootstrap, CORS, Docker
B	Jaimie	Middleware — validation, rate limiting, error handling, logging
C	Maxim	LLM integration — Groq API, prompt engineering, conversation history
D	Nam Khan	API routes, SQLite database, authentication, session persistence

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What each student built

Iulian built the full React frontend: a ChatGPT-style interface with a session sidebar, chat bubbles, markdown rendering, login and register pages, and protected routes. He also wrote the Express server entry point, CORS configuration, both Dockerfiles, and the docker-compose setup.

Jaimie wrote the middleware layer: input validation, a global error handler, rate limiting at 5 requests per second per IP, and a request logger.

Maxim built the LLM integration: the Groq API client, the system prompt defining the code reviewer persona, conversation history formatting, and per-language prompt hints.

Nam Khan implemented the API routes, SQLite database schema, and full authentication system. He added user registration and login with bcrypt password hashing, 7-day persistent tokens stored as cookies, and per-user session and message storage. Each user's chat history is isolated — no account can see another account's sessions.

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Running the project

1. Clone the repository

git clone https://github.com/<your-org>/code-reviewer.git
cd code-reviewer

2. Configure environment variables

cp backend/.env.example backend/.env

Open backend/.env and fill in your values:

LLM_PROVIDER=groq
LLM_MODEL=llama-3.3-70b-versatile
GROQ_API_KEY=your_groq_api_key_here
PORT=4000

Get a free Groq API key at https://console.groq.com

3. Build and start

docker-compose up --build -d

4. Open the app

Go to http://localhost:3000

5. Useful commands

docker-compose ps          # check running containers
docker-compose logs backend  # view backend logs
docker-compose down        # stop containers
docker-compose up --build -d  # rebuild after changes

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Authentication

Register

Go to http://localhost:3000/register

• Username must be at least 3 characters
• Password must be at least 6 characters
• Confirm password must match exactly — the form blocks submission if the two fields do not match
• If the username is already taken, the backend returns an error and registration is blocked

Login

Go to http://localhost:3000/login

• Enter your username and password
• On success, a 7-day session cookie is set automatically
• You stay logged in across page refreshes and browser restarts for 7 days

Session isolation

Each account has its own chat history. Sessions and messages are stored in SQLite and tied to the user who created them. Logging into a different account shows only that account's sessions — no chat history is shared or inherited between accounts.

Sign out

Click "Sign out" in the navbar. The session token is deleted from the database and the cookie is cleared immediately.

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API endpoints

Method	Endpoint	Description
POST	/api/auth/register	Create an account
POST	/api/auth/login	Login and receive session cookie
POST	/api/auth/logout	Invalidate session
GET	/api/auth/me	Check current session
GET	/api/sessions	Get all sessions for logged-in user
POST	/api/sessions	Create a new session
PATCH	/api/sessions/:id	Update session title
DELETE	/api/sessions/:id	Delete session and messages
GET	/api/sessions/:id/messages	Get messages for a session
POST	/api/sessions/:id/messages	Append a message
POST	/api/review	Submit code for AI review
GET	/api/health	Check server and model status

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