Financial Service

Query financial data on Yahoo.

Getting Started

1. Install dependencies npm install
2. Create your own environment file .env and fill the variables from .env.tmp e.g. ENV=development PORT=3000.
3. Run the service on your local machine via npm run dev. Hot reloading is available.
4. Open http://localhost:3000 and go to the ApolloGraphQL sandbox explorer
5. Use the following example and enter it into the ApolloGraphQL sandbox

Example Operation

query ($symbol: String, $from: String, $to: String, $interval: String) {
  quote(symbol: $symbol) {
    language
    region
    currency
    shortName
    longName
    market
    marketCap
    regularMarketPrice
    regularMarketDayHigh
    regularMarketDayLow
    regularMarketVolume
  },
  history(symbol: $symbol, from: $from, to: $to, interval: $interval) {
    date
    volume
    high
    low
  }
}

Example Variables

{
  "symbol": "AAPL",
  "from": "2023-09-01",
  "to": "2023-09-13",
  "interval": "1d",
}

Decisions

TypeScript: With TypeScript, the advantage of type safety through GraphQL is also implemented in the further code.

Apollo GraphQL: To implement GraphQL Apollo GraphQL is used. Apollo GraphQL is one of the most popular tools to integrate a GraphQL server and has a large community and ecosystem. In addition, the sandbox provides a simple and powerful tool to write GraphQL queries out of the box.

yahoo-finance2: To query financial data on Yahoo, yahoo-finance2 is used. The package has a high download rate compared to others, which corresponds to a good quality. Moreover, the package is actively maintained and well documented.