Stroid

English | 日本語

Stroid is a web application for checking stock, foreign exchange, and cryptocurrency prices through a simple interface. Enter a ticker symbol to display the current price, change, volume, and market time using data from Yahoo Finance. For stocks, pre-market or after-hours prices are also shown when available.

The frontend is built with HTML, CSS, and JavaScript. The price API is implemented in Python using yfinance. Bottle is used for local development, while the production setup uses GitHub Pages and AWS Lambda.

Features

• Search stock, foreign exchange, and cryptocurrency prices
• Display the current price, change, percentage change, volume, and market time
• Display pre-market and after-hours information for stocks
• Shortcuts for BTC/USD, ETH/USD, and USD/JPY
• Save and load a ticker symbol in the browser
• Compact interface for both desktop and mobile devices

Live Demo

https://berochlu.github.io/stroid/

Project Structure

.
├── public/                         # Static frontend
│   ├── index.html
│   └── static/
│       ├── script.js
│       ├── style.css
│       └── favicon.png
├── lambda/
│   └── lambda_function.py          # API for AWS Lambda
├── local_test.py                   # Local Bottle server
├── requirements.txt                # Python dependencies
├── run_Windows.bat                 # Windows startup script
└── .github/workflows/
    └── stroid-deploy-pages.yml      # Workflow that deploys public/ to GitHub Pages

Requirements

• Python 3 (uses zoneinfo)
• Internet connection

Yahoo Finance must be reachable to retrieve price data.

Running Locally

pip install -r requirements.txt
python local_test.py

After the server starts, open http://127.0.0.1:5400 in your browser.

The server listens on 0.0.0.0:5400. To access it from another device on the same network, use the Network URL displayed at startup.

Usage

1. Enter a Yahoo Finance ticker symbol in the input field.
2. Press update or the Enter key.
3. If needed, press save to store the ticker in browser LocalStorage and load to restore it.

Examples:

Asset	Ticker
Apple	AAPL
Toyota Motor	7203.T
Bitcoin / USD	BTC-USD
Ethereum / USD	ETH-USD
USD / JPY	JPY=X

The BTC, ETH, and $/¥ buttons place the corresponding ticker in the input field. Press update afterward to retrieve the price.

API

The local server provides the following GET endpoints.

GET /api/quote?t=AAPL
GET /quote?t=AAPL

Example:

curl "http://127.0.0.1:5400/api/quote?t=AAPL"

Example response:

{
  "ticker": "AAPL",
  "title": "Apple Inc. (AAPL)",
  "price": "210.50",
  "priceChange": "+1.25",
  "priceChangePercent": "(+0.60%)",
  "marketTime": "July 28 at 04:00:00 PM EDT",
  "volume": "Vol: 45,000,000",
  "postPrice": "210.80",
  "postPriceChange": "+0.30",
  "postPriceChangePercent": "(+0.14%)",
  "postMarketTime": "July 28 at 07:59:00 PM EDT"
}

Values are formatted as strings for display. If after-hours data or volume is unavailable, the corresponding fields are null.

Status	Condition
200	The price was retrieved successfully
400	The t query parameter is missing
500	The ticker was not found or the external data request failed

Deployment

In production, public/ is hosted on GitHub Pages, and lambda/lambda_function.py is called through an AWS Lambda Function URL.

Lambda

• Handler: lambda_function.lambda_handler
• Runtime: Python 3.13
• Dependency: yfinance
• Input: the t query parameter of the Function URL

When deploying to Lambda, include lambda_function.py and its dependencies in the deployment package, or add the dependencies as a Lambda Layer. CORS must also be configured so the Function URL can accept browser requests.

For detailed instructions on building and setting up the Lambda Layer, see AWS Lambda Layer Setup.

The frontend endpoint is selected by getApiUrl() in public/static/script.js. If the hostname or Lambda Function URL changes, update this function as well.

GitHub Pages Deployment

.github/workflows/stroid-deploy-pages.yml automatically deploys the contents of public/ to GitHub Pages on every push to the main branch.

Note: This workflow deploys only the static frontend files. lambda/lambda_function.py must be deployed to Lambda separately.

Development Notes

• local_test.py and lambda/lambda_function.py contain the same price retrieval logic. Update both when changing retrieved fields or formatting.
• Displayed prices and times depend on data available from Yahoo Finance; real-time accuracy and completeness are not guaranteed.
• After-hours trading is not checked for cryptocurrencies or foreign exchange.

License

MIT License