go-finance

README

go-finance

Fetches real-time and historical stock, crypto, and currency prices from Yahoo Finance and returns JSON output.

{"symbol":"AAPL","price":270.17,"currency":"USD"}

Prerequisites

• Go 1.22+
• golangci-lint

CLI usage

make build

# Current price
make run ARGS="AAPL"
make run ARGS="BTC-USD"
make run ARGS="USD-EUR"

# Monthly price (OHLC + average)
make run ARGS="AAPL --year 2024 --month 3"

# Yearly price (aggregated from quarterly data)
make run ARGS="AAPL --year 2024"

# Yearly price for a currency pair
make run ARGS="USD-RON --year 2015"

Output examples

Current price

{"symbol":"AAPL","price":270.17,"currency":"USD"}

Monthly (--year 2024 --month 3)

{"symbol":"AAPL","year":2024,"month":3,"open":179.55,"high":180.53,"low":168.49,"close":171.48,"avg":175.01}

Yearly (--year 2024)

{"symbol":"AAPL","year":2024,"open":187.15,"high":237.49,"low":164.08,"close":225.91,"avg":203.66}

Yearly — currency pair (USD-RON --year 2015)

{"symbol":"USD-RON","year":2015,"open":3.7029,"high":4.1851,"low":3.7029,"close":4.0333,"avg":3.9061}

Flags

Flag	Description
--year YEAR	Return historical data for the given year. Omit --month for yearly aggregate.
--month MONTH	Month (1–12). Requires --year.

Flags may appear before or after the ticker: go-finance AAPL --year 2024 and go-finance --year 2024 AAPL both work.

Using the package in another Go app

go get github.com/hackmajoris/go-finance@v0.1.0

package main

import (
    "context"
    "fmt"
    "log"

    "github.com/hackmajoris/go-finance/pkg/yahoo"
)

func main() {
    client, err := yahoo.New()
    if err != nil {
        log.Fatal(err)
    }

    ctx := context.Background()

    // Current price — single symbol
    quote, err := client.GetQuote(ctx, "USD-EUR")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(quote.Symbol, quote.Price, quote.Currency)

    // Current prices — multiple symbols in parallel (returns map[symbol]price)
    prices, err := client.FetchQuotes(ctx, []string{"AAPL", "BTC-USD", "BRK B"})
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(prices["AAPL"], prices["BTC-USD"], prices["BRK-B"])

    // FX rates relative to a base currency — fetched in parallel
    rates, err := client.FetchFXRates(ctx, []string{"EUR", "RON", "USD"}, "USD")
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(rates["EUR"], rates["RON"]) // rates["USD"] == 1.0

    // Normalize broker tickers to Yahoo Finance format ("BRK B" → "BRK-B")
    fmt.Println(yahoo.NormalizeTicker("BRK B"))

    // Monthly OHLC
    bar, err := client.GetMonthlyBar(ctx, "AAPL", 2024, 3)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(bar.Open, bar.High, bar.Low, bar.Close, bar.Avg)

    // Yearly OHLC (aggregated from 4 quarters)
    yearly, err := client.GetYearlyBar(ctx, "AAPL", 2024)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(yearly.Open, yearly.High, yearly.Low, yearly.Close, yearly.Avg)

    // Yearly OHLC for a currency pair
    forexYearly, err := client.GetYearlyBar(ctx, "USD-RON", 2015)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println(forexYearly.Open, forexYearly.High, forexYearly.Low, forexYearly.Close, forexYearly.Avg)
}

GetQuote accepts any Yahoo Finance symbol — stocks (AAPL), crypto (BTC-USD), and currency pairs (USD-EUR, RON-USD).

FetchQuotes fetches multiple symbols in parallel via the v8 chart endpoint (no crumb required) and returns a map[string]float64. Both the original ticker and its normalized form (e.g. "BRK B" and "BRK-B") are stored in the map.

FetchFXRates fetches spot rates for a list of currencies relative to a base currency in parallel. The base currency always gets rate 1.0.

NormalizeTicker converts broker-style tickers to Yahoo Finance format (spaces → hyphens).

GetMonthlyBar and GetYearlyBar accept any Yahoo Finance symbol — stocks (AAPL), crypto (BTC-USD), and currency pairs (USD-RON).

Development(examples)

make build                          # compile binary to .bin/go-finance
make run ARGS="AAPL"                # current price
make run ARGS="AAPL --year 2024"    # yearly
make run ARGS="AAPL --year 2024 --month 3"  # monthly
make test                           # run tests with race detector
make lint                           # run linter

License

MIT