How I Built a Japan Travel App with Next.js and FastAPI

Last year I decided to plan a trip to Japan. I quickly realized that information about Japan travel is scattered across dozens of websites, each with different formats and outdated prices.

So I built ViajApp - a complete Japan travel platform with API, web app, and soon mobile.

The Stack

• Frontend: Next.js 16 with TypeScript
• Backend: FastAPI (Python)
• Database: Supabase (PostgreSQL)
• Hosting: Vercel + Render

Features I Built

1. Restaurant Search with Serper API

Real-time search for restaurants, temples, and attractions using Google Places data.

2. Currency Converter

Live exchange rates updated daily. No more mental math at konbini.

3. Transport Calculator

Calculate the best route between cities with JR Pass recommendations.

4. Blog Auto-Generation

This article you're reading was automatically generated and posted via GitHub Actions. Every week, a new article about Japan travel is created and published to both the website and Dev.to.

5. Emergency Info

Real-time weather, emergency numbers, and hospital finder for each region.

The API

The backend has 40+ endpoints covering:

• Culture guides
• Food recommendations
• Budget calculator
• Event finder
• Transport info
• Emergency services

Lessons Learned

1. Start with the data: Before writing code, I collected all the Japan travel information I could find
2. API-first design: Building the API first made the frontend much easier
3. Automation is key: The blog auto-generation saves hours every week
4. SEO matters: Each article has metadata, tags, and structured content

What's Next

• Mobile app (React Native)
• AI-powered itinerary generator
• More countries (Greece, Italy, Spain)

Try It

🌐 Web: viajapp.app
📡 API: japan-travel-api.onrender.com

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Built with love for Japan 🇯🇵