Shortly — A Minimal URL Shortener API in Go

Shortly is a clean and minimalistic URL shortener built entirely in Go with SQLite as a local storage engine. This project was created as a learning exercise to understand how to:

• Accept and process data via HTTP
• Build a REST API in Go
• Handle persistent data with a relational database

📘 The focus was not on production readiness, but on building something clear and functional to learn Go’s net/http, database/sql, and API patterns.

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✨ Features

• ✅ POST /shorten to create a short URL
• ✅ Optional expiration support (expires_in_minutes)
• ✅ Expired links return a 410 Gone status
• ✅ Expired links are automatically cleaned from the database
• ✅ Duplicate detection (same original URL returns the same short ID)
• ✅ GET /{shortID} to redirect users to the original URL
• ✅ SQLite-backed storage (no external dependencies)
• ✅ Fully local and lightweight

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📦 Project Structure

shortly/
├── cmd/             # Server entrypoint
├── internal/
│   ├── api/         # HTTP handlers
│   ├── storage/     # SQLite database logic
│   └── utils/       # Short ID generator
├── go.mod
└── README.md

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🧪 API Usage

🔗 Shorten a URL

Request

curl -X POST http://localhost:8080/shorten `
     -H "Content-Type: application/json" `
     -Body '{ "original_url": "https://example.com", "expires_in_minutes": 60 }'

Response

{
  "short_url": "http://localhost:8080/abc123"
}

🚀 Redirect

Visiting http://localhost:8080/abc123 will redirect you to https://example.com.
If the link has expired, you will receive a 410 Gone response with a clear message.

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🧼 Automatic Expiration Cleanup

Expired URLs are automatically removed:

• On server startup

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🛠️ Getting Started

🔧 Requirements

• Go 1.21+
• No external DB or services

🧰 Run the app

go run ./cmd/server

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💡 What I Learned

This project helped me learn how to:

• Build a REST API from scratch in Go
• Handle JSON input/output with validation
• Store and retrieve data with SQLite and SQL queries
• Implement time-based expiration and automatic cleanup
• Write modular and extensible backend code

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🛠 Future Enhancements (Ideas)

• Track visit counts per URL
• Rate limiting or API keys
• Frontend UI for generating and managing links
• User authentication and per-user links
• Hosting and deployment via Docker

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📄 License

MIT — open source and free to use for learning or personal projects.