Cover Letter Generator

A web app that generates personalized cover letters from job descriptions and user details, then renders the output into a downloadable PDF.

The app now uses OpenRouter only for LLM generation, with the allowed model list defined in YAML and surfaced in the UI dropdown.

Features

• OpenRouter-powered cover letter generation
• Job application question answering using the same resume/projects context
• Resume PDF tailoring from structured resume.yaml
• YAML-driven model allowlist (config/model.yaml)
• Backend model validation (rejects unknown slugs)
• React frontend with model dropdown fetched from backend
• PDF generation and download
• Dockerized deployment

Architecture

• frontend/: React app
• backend/: Flask app serving APIs + frontend build
• backend/api_service/: Prompt construction, model config loading, OpenRouter calls
• backend/models/: Pydantic schemas for structured LLM outputs
• pdf_service/: ReportLab PDF generation
• resume.yaml: Structured resume source used for tailored resume generation
• config/: YAML model configuration
• static/: Resume and static assets

Prerequisites

• Python 3.9+
• Node.js 18+
• OpenRouter API key

Setup

1. Install backend dependencies

python -m venv .venv
source .venv/bin/activate
pip install -r backend/requirements.txt

2. Install frontend dependencies

cd frontend
npm install
cd ..

3. Configure environment variables

Create .env:

OPENROUTER_API_KEY=your_openrouter_api_key_here
# Optional attribution headers:
# OPENROUTER_HTTP_REFERER=https://your-app-domain.com
# OPENROUTER_APP_TITLE=Cover Letter Generator

4. Configure model catalog

Edit config/model.yaml:

openrouter:
  base_url: https://openrouter.ai/api/v1
  default_model: openai/gpt-4.1-mini
  models:
    - label: GPT-4.1 Mini
      slug: openai/gpt-4.1-mini

5. Add resume context

Place your resume PDF at static/resume.pdf for cover-letter and question-answer context. Edit resume.yaml for generated resume content; the backend renders tailored resume PDFs from this YAML file.

Running

Quick start

chmod +x run.sh
./run.sh

• Frontend: http://localhost:3002
• Backend: http://localhost:5000

Manual

source .venv/bin/activate
python backend/app.py

In another terminal:

cd frontend
PORT=3002 npm start

Docker

docker build -t cover-letter-generator .
docker run -p 8080:8080 -e OPENROUTER_API_KEY=your_key_here cover-letter-generator

API Endpoints

• GET /api/models: Returns configured model list and default model
• POST /api/analyze: Generates cover letter text using selected model slug (or default)
• POST /api/answer-questions: Generates answers for pasted application questions using the same candidate context
• POST /api/generate-resume: Generates a tailored resume PDF from resume.yaml
• POST /api/generate-pdf: Builds PDF from generated text
• GET /api/download/<filename>: Downloads generated PDF

Notes

• Backend enforces model allowlist from config/model.yaml.
• Backend loads YAML at startup and fails fast if invalid.
• POST /api/analyze returns 400 for unknown model slugs.