Job Board Backend API 🚀

A production-ready, secure, and scalable REST API for a job board platform. This project demonstrates advanced backend engineering practices, including Role-Based Access Control (RBAC), PostgreSQL Full-Text Search Optimization, and Automated API Documentation.

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🏗️ Architecture & Features

This system was built with a "Security First" and "Performance First" mindset, moving beyond basic CRUD operations to handle real-world scale and threats.

1. 🔐 Advanced Security (RBAC)

• Custom User Model: Implemented a scalable CustomUser model extending AbstractUser to support distinct roles (Admin, Employer, Job Seeker) without bloat.
• Row-Level Access Control:
  • Employers: Can only edit/delete their own job postings.
  • Applicants: Can only view their own applications.
  • Employers: Can only view applications for their specific jobs.
• JWT Authentication: Secure stateless authentication using simplejwt with short-lived access tokens.

2. ⚡ High-Performance Search

• The Problem: Standard SQL LIKE queries are slow (O(n)) and fail on complex text.
• The Solution: Implemented PostgreSQL GIN (Generalized Inverted Index).
• Implementation: Used Django's SearchVector to combine title and description fields into a lexeme vector, enabling instant O(1) text search capabilities.

3. 📄 Automated Documentation

• Integrated Drf-Spectacular to generate OpenApi 3.0 schema.
• Swagger UI: Fully interactive frontend for testing endpoints directly from the browser.
• Custom Schema Extensions: Manually extended the auto-schema to document complex query parameters like ?search=.

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🛠️ Tech Stack

Category	Technology	Purpose
Framework	Django 5.0 + DRF	Rapid, secure API development
Database	PostgreSQL	Relational data + Full-Text Search Engine
Auth	JWT (SimpleJWT)	Stateless, secure token-based auth
Docs	Drf-Spectacular	Swagger/OpenAPI generation
Indexing	GIN Index	High-performance text querying

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🧪 Testing the API Once the server is running, access the interactive documentation:

Swagger UI: http://127.0.0.1:8000/api/docs/

Redoc: http://127.0.0.1:8000/api/schema/redoc/

Key Endpoints Method,Endpoint,Description,Access POST,/api/auth/token/,Get Access/Refresh Tokens,Public GET,/api/jobs/postings/,List all jobs,Public GET,/api/jobs/postings/?search=python,Search using GIN Index,Public POST,/api/jobs/postings/,Create a job,Employer Only POST,/api/jobs/applications/,Apply for a job,Authenticated

Challenge: The "Invisible Parameter" Issue: The Swagger UI was not showing the search parameter because we handled the logic manually in get_queryset.

Solution: Used @extend_schema from drf_spectacular to explicitly inject the search parameter definition into the OpenAPI schema, making it visible and testable for frontend developers.

Challenge: Security vs. Usability Issue: We needed Employers to post jobs easily, but we couldn't trust them to manually input their user ID (security risk).

Solution: Overrode perform_create in the ViewSet to automatically inject self.request.user as the employer, ensuring data integrity while keeping the API simple.

📜 License This project is part of the ProDev Backend Engineering Program.