Simple Calculator App

Simple Calculator App

A clean one-page calculator app built with Codexirra, using a React, Vite, TypeScript frontend and a FastAPI backend.

This template was generated with Codexirra, an AI development workspace for building real web applications. Codexirra helps you generate, edit, preview, and refine full web apps from simple prompts.

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Built with Codexirra

This project is an example of what can be created using Codexirra.

Codexirra can help generate complete web applications with:

• Frontend pages and components
• Backend API routes
• Clean UI layouts
• Forms, tables, dashboards, and app logic
• Full project structure
• Editable code and live preview

This calculator template is intentionally simple, making it a good starter example for testing a full frontend and backend app structure.

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What this app does

• Adds, subtracts, multiplies, divides, and calculates modulo.
• Supports decimal numbers and keyboard input.
• Shows clear loading and error states.
• Keeps the five most recent calculations on the page.
• Uses a real backend endpoint for safe expression evaluation.

Project structure

/
  src/                 React frontend
  backend/app/main.py  FastAPI backend

Frontend

Install dependencies:

npm install

Run the frontend:

npm run dev

Build the frontend:

npm run build

The frontend API client reads VITE_API_URL or VITE_API_BASE_URL when provided. If neither is configured, it uses same-origin /api. The helper always normalizes the base so calls go to /api/calculate.

Backend

Install backend dependencies:

cd backend
pip install -r requirements.txt

Run the API:

uvicorn app.main:app --reload

Available backend routes:

• GET /api/health
• POST /api/calculate

Usage

Open the app, tap the calculator buttons, or use your keyboard:

• Number keys enter digits.
• +, -, *, /, %, and . enter operators and decimals.
• Enter solves.
• Backspace deletes one character.
• Escape clears the calculator.