CyFinance 0.0.49

Yahoo Finance API Client Library

This is a C# client library designed to interact with the Yahoo Finance API.

Documentation

Static documentation is published to GitHub Pages by the .github/workflows/publish-nuget.yml workflow. The first release includes the API reference plus a few short guides.

To generate the site locally:

dotnet tool restore
dotnet run --project pipelines/CyFinance.Pipelines/CyFinance.Pipelines.csproj --configuration Release

The generated site is written to artifacts/docs.

The project was originally a fork of dougdellolio/YahooFinanceAPI. However, due to significant changes in Yahoo’s API, the library has been rebuilt from scratch with the goal of providing a C# implementation that closely mirrors the popular Python library yfinance.

Features Parity

The table below outlines the current feature parity between yfinance and this C# library (CyFinance):

Feature	yfinance (Python)	CyFinance (C#)	API Used
Current Quote Data	✅	✅	Quote Summary API
Historical Price Data	✅	✅	Chart/Historical Data API
Company Information (Profile, Summary)	✅	⚠️ Limited	Quote Summary API
Financial Statements (Income, Balance Sheet, Cash Flow)	✅	✅	Financial Statements API
Dividends & Splits History	✅	✅ (Current dividend data only)	Chart/Historical Data API
Analyst Recommendations	✅	✅	Analyst Recommendations
Shareholder Information (Major, Institutional)	✅	✅	Shareholder Information
Earnings Calendar	✅	✅	Earnings Calendar
Company News	✅	✅	Company News
Option Chains	✅	✅	Options Data API
Quote Search	✅	✅	Search API
Stock Screening (Screener API)	✅	✅	Screener API
Multi-Ticker Data Download	✅	❌	Quote API (Real-time)
Market Status & Summary	✅	✅	Market Status and Summary API
Sector Domain Data	✅	✅	Sector/Industry APIs
Industry Domain Data	✅	✅	Sector/Industry APIs
Global Calendars (Earnings, IPO, Splits, Economic Events)	✅	✅	Global Calendars API
Live Streaming (WebSocket)	✅	❌	WebSocket Streaming API
Mutual Fund / ETF Data	✅	✅	Mutual Fund/ETF Data API
Currency / Forex Data	✅	✅	Currency/Forex API
Cryptocurrency Data	✅	✅	Cryptocurrency API

Facade API (CyFinanceClient)

CyFinance exposes a facade client (CyFinanceClient) so you can access all service APIs from a single DI-resolved entry point.

Setup

using CyFinance;
using CyFinance.DependencyInjection;
using Microsoft.Extensions.DependencyInjection;

var services = new ServiceCollection();
services.AddCyFinance();

await using var provider = services.BuildServiceProvider();
var client = provider.GetRequiredService<CyFinanceClient>();

Facade API map

Facade Property	Service Interface
client.QuoteSummary	IQuoteSummaryService
client.HistoricalData	IHistoricalDataService
client.OptionsData	IOptionsDataService
client.Search	ISearchService
client.StockScreening	IStockScreeningService
client.Market	IMarketSummaryService
client.Calendars	IGlobalCalendarsService
client.EarningsCalendar	IEarningsCalendarService
client.FinancialStatements	IFinancialStatementsService
client.AnalystRecommendations	IAnalystRecommendationsService
client.ShareholderInformation	IShareholderInformationService
client.CompanyNews	ICompanyNewsService
client.FundData	IFundDataService
client.SectorIndustry	ISectorIndustryService
client.Currency	ICurrencyService
client.Crypto	ICryptoService

Facade examples (each API)

1. Quote Summary API

var quote = await client.QuoteSummary.GetQuoteSummaryAsync("AAPL", "price", "summaryDetail");
Console.WriteLine(quote?.QuoteSummary?.Result?[0]?.Price?.LongName);

2. Historical Data API

var prices = await client.HistoricalData.GetHistoricalPricesAsync("MSFT");
Console.WriteLine($"Historical points: {prices.Count}");

3. Options Data API

var expirations = await client.OptionsData.GetExpirationDatesAsync("AAPL");
Console.WriteLine($"Option expirations: {expirations.Count}");

4. Search API

var search = await client.Search.SearchAsync("NVIDIA", quotesCount: 5, newsCount: 2);
Console.WriteLine($"Quotes returned: {search?.Quotes?.Count ?? 0}");

5. Stock Screening API

var gainers = await client.StockScreening.ScreenPredefinedAsync(PredefinedScreenersCatalogItem.DayGainers);
Console.WriteLine(gainers is not null ? "Screener request complete" : "No screener data returned");

6. Market Summary API

var snapshot = await client.Market.GetMarketSnapshotAsync("US");
Console.WriteLine($"Market open time: {snapshot?.Status?.Open}");

7. Global Calendars API

var earnings = await client.Calendars.GetEarningsCalendarAsync(limit: 10);
Console.WriteLine($"Upcoming earnings events: {earnings.Count}");

8. Earnings Calendar API

var earningsCalendar = await client.EarningsCalendar.GetEarningsCalendarAsync("AAPL");
Console.WriteLine($"Next earnings unix date: {earningsCalendar?.GetNextEarningsDate()}");

9. Financial Statements API

var statements = await client.FinancialStatements.GetAllStatementsAsync("AAPL");
Console.WriteLine(statements is not null ? "Statements loaded" : "No statements returned");

10. Analyst Recommendations API

var recommendations = await client.AnalystRecommendations.GetRecommendationsAsync("AAPL");
Console.WriteLine($"Consensus rating: {recommendations?.GetConsensusRating()}");

11. Shareholder Information API

var holders = await client.ShareholderInformation.GetShareholderInformationAsync("AAPL");
Console.WriteLine($"Institutional ownership: {holders?.GetInstitutionalOwnershipPercent():F2}%");

12. Company News API

var latestNews = await client.CompanyNews.GetLatestCompanyNewsAsync("AAPL");
Console.WriteLine(latestNews?.Title);

13. Fund Data API

var fund = await client.FundData.GetFundSummaryAsync("VOO");
Console.WriteLine($"Fund name: {fund?.Name}");

14. Sector/Industry API

var sectorInfo = await client.SectorIndustry.GetSectorInfoAsync("AAPL");
Console.WriteLine($"{sectorInfo?.Sector} / {sectorInfo?.Industry}");

15. Currency API

var eurUsd = await client.Currency.GetExchangeRateAsync("EUR", "USD");
Console.WriteLine($"EUR/USD: {eurUsd?.Rate}");

16. Crypto API

var btc = await client.Crypto.GetCryptoQuoteAsync("BTC", "USD");
Console.WriteLine($"BTC/USD: {btc?.Price}");

Which internal APIs are used by yfinance ?

Info from Claude, based on analysis of the yfinance library source code and documentation.

Core Data Endpoints

1. Chart/Historical Data API

• Endpoint: https://query2.finance.yahoo.com/v8/finance/chart/{ticker}
• Purpose: Historical price data, volume, and chart information
• Parameters:
  • period1 & period2: Unix timestamps for date range
  • interval: Time intervals (1m, 2m, 5m, 15m, 30m, 1h, 1d, 5d, 1wk, 1mo, 3mo)
  • events: dividends, splits
• Usage: Primary endpoint for .history() method

2. Quote Summary API

• Endpoint: https://query2.finance.yahoo.com/v10/finance/quoteSummary/{ticker}
• Purpose: Comprehensive ticker information including financials, statistics, and company data
• Modules:
  • assetProfile: Company profile and business description
  • summaryProfile: Basic company information
  • summaryDetail: Current price and market data
  • esgScores: ESG (Environmental, Social, Governance) ratings
  • price: Real-time price information
  • incomeStatementHistory: Annual income statements
  • incomeStatementHistoryQuarterly: Quarterly income statements
  • balanceSheetHistory: Annual balance sheets
  • balanceSheetHistoryQuarterly: Quarterly balance sheets
  • cashflowStatementHistory: Annual cash flow statements
  • cashflowStatementHistoryQuarterly: Quarterly cash flow statements
  • defaultKeyStatistics: Key financial metrics
  • financialData: Real-time financial data
  • calendarEvents: Upcoming earnings and events
  • secFilings: SEC filing information
  • recommendationTrend: Analyst recommendations
  • upgradeDowngradeHistory: Analyst upgrades/downgrades
  • institutionOwnership: Institutional ownership data
  • fundOwnership: Fund ownership data
  • majorDirectHolders: Major direct shareholders
  • majorHoldersBreakdown: Ownership breakdown
  • insiderTransactions: Insider trading activity
  • insiderHolders: Insider holdings
  • netSharePurchaseActivity: Share buyback activity
  • earnings: Earnings data and estimates
  • earningsHistory: Historical earnings
  • earningsTrend: Earnings trend and estimates
  • industryTrend: Industry-wide trends
  • indexTrend: Index trend data
  • sectorTrend: Sector trend data

2.5 Financial Statements API

• Endpoint: Uses https://query2.finance.yahoo.com/v10/finance/quoteSummary/{ticker} under the hood
• Purpose: Simplified access to income statements, balance sheets, and cash flow statements
• Usage: Used by FinancialStatementsService class

Financial Statements

• Income statement data via GetIncomeStatementAsync(ticker) - Returns annual and quarterly data
• Balance sheet data via GetBalanceSheetAsync(ticker) - Returns annual and quarterly data
• Cash flow statement data via GetCashFlowStatementAsync(ticker) - Returns annual and quarterly data
• All statements via GetAllStatementsAsync(ticker) - Returns all three statement types
• Custom module selection via GetStatementsAsync(ticker, params string[] modules)

Facade example (showcase all methods):

var incomeStatement = await client.FinancialStatements.GetIncomeStatementAsync("AAPL");
var balanceSheet = await client.FinancialStatements.GetBalanceSheetAsync("AAPL");
var cashFlow = await client.FinancialStatements.GetCashFlowStatementAsync("AAPL");
var allStatements = await client.FinancialStatements.GetAllStatementsAsync("AAPL");
var customStatements = await client.FinancialStatements.GetStatementsAsync(
  "AAPL",
  "incomeStatementHistory",
  "balanceSheetHistory");

Console.WriteLine(incomeStatement is not null ? "Income statement loaded" : "No income statement");
Console.WriteLine(balanceSheet is not null ? "Balance sheet loaded" : "No balance sheet");
Console.WriteLine(cashFlow is not null ? "Cash flow loaded" : "No cash flow");
Console.WriteLine(allStatements is not null ? "All statements loaded" : "No full statement payload");
Console.WriteLine(customStatements is not null ? "Custom statement modules loaded" : "No custom module payload");

2.6 Analyst Recommendations

• Endpoint: Uses https://query2.finance.yahoo.com/v10/finance/quoteSummary/{ticker} under the hood
• Purpose: Simplified access to analyst recommendations and rating changes
• Usage: Used by AnalystRecommendationsService class

Analyst Recommendations

• Recommendation trend data via GetRecommendationTrendAsync(ticker) - Returns analyst sentiment over time
• Rating change history via GetRatingChangeHistoryAsync(ticker) - Returns upgrades/downgrades
• Complete recommendations summary via GetRecommendationsAsync(ticker) - Returns both trend and history with convenience methods

Convenience Methods:

• GetConsensusRating() - Calculates consensus rating (Strong Buy, Buy, Hold, Sell, Strong Sell)
• GetRecommendationPercentages() - Returns percentage breakdown of recommendations

Facade example (showcase all methods):

var recommendations = await client.AnalystRecommendations.GetRecommendationsAsync("AAPL");
var trend = await client.AnalystRecommendations.GetRecommendationTrendAsync("AAPL");
var history = await client.AnalystRecommendations.GetRatingChangeHistoryAsync("AAPL");

Console.WriteLine($"Consensus: {recommendations?.GetConsensusRating()}");
Console.WriteLine($"Trend points: {trend?.Count ?? 0}");
Console.WriteLine($"Rating changes: {history?.Count ?? 0}");

var breakdown = recommendations?.GetRecommendationPercentages();
foreach (var (rating, percentage) in breakdown ?? new Dictionary<string, double>())
{
  Console.WriteLine($"{rating}: {percentage:F1}%");
}

2.7 Shareholder Information

• Endpoint: Uses https://query2.finance.yahoo.com/v10/finance/quoteSummary/{ticker} under the hood
• Purpose: Simplified access to major holders, institutional/fund ownership, and insider ownership data
• Usage: Used by ShareholderInformationService class

Shareholder Information

• Major holders breakdown via GetMajorHoldersBreakdownAsync(ticker)
• Institutional ownership list via GetInstitutionalOwnershipAsync(ticker)
• Fund ownership list via GetFundOwnershipAsync(ticker)
• Insider holders list via GetInsiderHoldersAsync(ticker)
• Insider transactions via GetInsiderTransactionsAsync(ticker)
• Full aggregate payload via GetShareholderInformationAsync(ticker)

Convenience Methods:

• GetInstitutionalOwnershipPercent()
• GetInsiderOwnershipPercent()
• GetLargestInstitutionalHolder()

Facade example (showcase all methods):

var shareholders = await client.ShareholderInformation.GetShareholderInformationAsync("AAPL");
var major = await client.ShareholderInformation.GetMajorHoldersBreakdownAsync("AAPL");
var institutions = await client.ShareholderInformation.GetInstitutionalOwnershipAsync("AAPL");
var funds = await client.ShareholderInformation.GetFundOwnershipAsync("AAPL");
var insiders = await client.ShareholderInformation.GetInsiderHoldersAsync("AAPL");
var insiderTransactions = await client.ShareholderInformation.GetInsiderTransactionsAsync("AAPL");

Console.WriteLine($"Institutional Ownership: {shareholders?.GetInstitutionalOwnershipPercent():F2}%");
Console.WriteLine($"Insider Ownership: {shareholders?.GetInsiderOwnershipPercent():F2}%");
Console.WriteLine($"Largest Holder: {shareholders?.GetLargestInstitutionalHolder()?.Organization}");
Console.WriteLine($"Major holders payload: {(major is not null ? "yes" : "no")}");
Console.WriteLine($"Institutions: {institutions?.Count ?? 0}, Funds: {funds?.Count ?? 0}");
Console.WriteLine($"Insider holders: {insiders?.Count ?? 0}, Insider transactions: {insiderTransactions?.Count ?? 0}");

2.8 Earnings Calendar

• Endpoint: Uses https://query2.finance.yahoo.com/v10/finance/quoteSummary/{ticker} under the hood
• Purpose: Simplified access to upcoming earnings dates and historical earnings surprises
• Usage: Used by EarningsCalendarService class

Earnings Calendar

• Upcoming earnings dates via GetUpcomingEarningsAsync(ticker)
• Historical quarterly earnings via GetHistoricalEarningsAsync(ticker)
• Combined earnings snapshot via GetEarningsCalendarAsync(ticker)

Facade example (showcase all methods):

var upcoming = await client.EarningsCalendar.GetUpcomingEarningsAsync("AAPL");
var historical = await client.EarningsCalendar.GetHistoricalEarningsAsync("AAPL");
var earnings = await client.EarningsCalendar.GetEarningsCalendarAsync("AAPL");

Console.WriteLine($"Upcoming entries: {upcoming?.EarningsDates?.Count ?? 0}");
Console.WriteLine($"Historical entries: {historical?.Quarterly?.Count ?? 0}");
Console.WriteLine($"Next Earnings Date (unix): {earnings?.GetNextEarningsDate()}");
Console.WriteLine($"Most Recent Earnings Date: {earnings?.GetMostRecentEarningsDate()}");
Console.WriteLine($"Beat Rate: {earnings?.GetEarningsBeatRate():F1}%");

2.9 **Company News

• Endpoint: Uses https://query2.finance.yahoo.com/v1/finance/search under the hood
• Purpose: Ticker-specific news headlines and article metadata
• Usage: Used by CompanyNewsService class

Company News

• Company news list via GetCompanyNewsAsync(ticker, newsCount)
• Latest company headline via GetLatestCompanyNewsAsync(ticker)
• Filtered recent company news via GetCompanyNewsSinceAsync(ticker, sinceUnixTime, newsCount)

Facade example (showcase all methods):

var allNews = await client.CompanyNews.GetCompanyNewsAsync("AAPL", newsCount: 10);
var latest = await client.CompanyNews.GetLatestCompanyNewsAsync("AAPL");
var oneDayAgo = DateTimeOffset.UtcNow.AddDays(-1).ToUnixTimeSeconds();
var recentNews = await client.CompanyNews.GetCompanyNewsSinceAsync("AAPL", oneDayAgo, newsCount: 20);

Console.WriteLine($"News count: {allNews?.Count ?? 0}");
Console.WriteLine($"Latest: {latest?.Title}");
Console.WriteLine($"Recent since yesterday: {recentNews?.Count ?? 0}");

3. Options Data API

• Endpoint: https://query2.finance.yahoo.com/v7/finance/options/{ticker}
• Purpose: Options chain data
• Parameters:
  • date: Expiration date (Unix timestamp)
• Usage: Used by .option_chain() method

Options chain

• Full option chain retrieval via GetOptionsChainAsync(ticker, date)
• Available expiration dates via GetExpirationDatesAsync(ticker)
• Expiration-specific chain via GetOptionsForExpirationAsync(ticker, expirationDate)
• Calls-only helper via GetCallsAsync(ticker, date)
• Puts-only helper via GetPutsAsync(ticker, date)

Facade example (showcase all methods):

var chain = await client.OptionsData.GetOptionsChainAsync("AAPL");
var expirations = await client.OptionsData.GetExpirationDatesAsync("AAPL");
var expiration = expirations.FirstOrDefault();

if (expiration != 0)
{
  var byExpiration = await client.OptionsData.GetOptionsForExpirationAsync("AAPL", expiration);
  var calls = await client.OptionsData.GetCallsAsync("AAPL", expiration);
  var puts = await client.OptionsData.GetPutsAsync("AAPL", expiration);

  Console.WriteLine($"Expiration {expiration}: calls={calls.Count}, puts={puts.Count}");
  Console.WriteLine(byExpiration is not null ? "Expiration chain loaded" : "No expiration data");
}

Console.WriteLine(chain is not null ? "Full chain loaded" : "No options chain");
Console.WriteLine($"Available expirations: {expirations.Count}");

4. Search API

• Endpoint: https://query2.finance.yahoo.com/v1/finance/search
• Purpose: Search for tickers, news, and quotes
• Parameters:
  • q: Search query
  • quotesCount: Number of quote results
  • newsCount: Number of news results
• Usage: Used by SearchService class

Search API

• Search for tickers and quotes via SearchAsync(query, quotesCount, newsCount)
• Separate methods for quotes-only search: SearchQuotesAsync(query, quotesCount)
• Separate methods for news-only search: SearchNewsAsync(query, newsCount)
• Returns structured results with multiple result types: quotes, news, research, nav

Facade example (showcase all methods):

var results = await client.Search.SearchAsync("Apple", quotesCount: 10, newsCount: 5);
var quotes = await client.Search.SearchQuotesAsync("Tesla", quotesCount: 5);
var news = await client.Search.SearchNewsAsync("Microsoft", newsCount: 3);

Console.WriteLine($"All search quotes: {results?.Quotes?.Count ?? 0}");
Console.WriteLine($"Quotes-only count: {quotes?.Count ?? 0}");
Console.WriteLine($"News-only count: {news?.Count ?? 0}");

5. Screener API

• Endpoint: https://query2.finance.yahoo.com/v1/finance/screener
• Purpose: Stock screening and filtering
• Usage: Used by Screener and EquityQuery classes

Screener

• Custom screener query via POST /v1/finance/screener (equivalent to yf.screen(query=...))
• Predefined screener query via GET /v1/finance/screener/predefined/saved?scrIds=...
• Query operators supported in request model:
  • EQ, IS-IN, BTWN, GT, LT, GTE, LTE, AND, OR
• Paging/sorting fields supported in request model:
  • offset, size, sortField, sortType, quoteType, userId, userIdType

Screener catalog and typed helpers

• Predefined screener catalog available via PredefinedScreeners constants and PredefinedScreenersCatalogItem enum
• Typed query helpers available:
  • EquityQuery
  • FundQuery
  • ETFQuery

Facade example (showcase all methods):

var query = EquityQuery.And(
  EquityQuery.Eq("region", "us"),
  EquityQuery.Gte("intradaymarketcap", 2_000_000_000),
  EquityQuery.Gt("dayvolume", 15_000));

var typedResult = await client.StockScreening.ScreenAsync(
  query,
  size: 25,
  sortField: "percentchange",
  sortAsc: false);

var request = new ScreenerRequest
{
  Size = 25,
  SortField = "percentchange",
  Query = query.ToNode()
};

var requestResult = await client.StockScreening.ScreenAsync(request);

var predefinedByEnum = await client.StockScreening.ScreenPredefinedAsync(PredefinedScreenersCatalogItem.DayGainers);
var predefinedByString = await client.StockScreening.ScreenPredefinedAsync("day_gainers");

Console.WriteLine(typedResult is not null ? "Typed screener loaded" : "No typed screener result");
Console.WriteLine(requestResult is not null ? "Request-based screener loaded" : "No request-based screener result");
Console.WriteLine(predefinedByEnum is not null ? "Predefined enum screener loaded" : "No predefined enum screener result");
Console.WriteLine(predefinedByString is not null ? "Predefined string screener loaded" : "No predefined string screener result");

6. News API

• Endpoint: https://query2.finance.yahoo.com/v2/finance/news
• Purpose: Financial news related to specific tickers
• Usage: Used for .news property

7. Spark Chart API

• Endpoint: https://query2.finance.yahoo.com/v8/finance/spark
• Purpose: Lightweight chart data for quick price updates
• Parameters:
  • symbols: Comma-separated ticker symbols
  • range: Time range (1d, 5d, 1mo, etc.)
  • interval: Data interval

Market Data APIs

8. Market Status and Summary API

• Summary Endpoint: https://query1.finance.yahoo.com/v6/finance/quote/marketSummary
• Status Endpoint: https://query1.finance.yahoo.com/v6/finance/markettime
• Purpose: Market indices, summary moves, trading session windows, and timezone information
• Usage: Used by MarketSummaryService class

Market Status and Summary API

• Market summary by Yahoo market code via GetMarketSummaryAsync(market)
• Market status/time window via GetMarketStatusAsync(market)
• Combined snapshot via GetMarketSnapshotAsync(market)
• Yahoo market codes mirrored from yfinance usage include: US, GB, ASIA, EUROPE, RATES, COMMODITIES, CURRENCIES, CRYPTOCURRENCIES

Facade example (showcase all methods):

var summary = await client.Market.GetMarketSummaryAsync("US");
var status = await client.Market.GetMarketStatusAsync("US");
var snapshot = await client.Market.GetMarketSnapshotAsync("US");

Console.WriteLine($"Summary exchanges: {summary?.Count ?? 0}");
Console.WriteLine($"Open: {status?.Open}, Close: {status?.Close}");
Console.WriteLine($"Snapshot exchanges: {snapshot?.SummaryByExchange?.Count ?? 0}");

9. Trending Tickers API

• Endpoint: https://query2.finance.yahoo.com/v1/finance/trending/{region}
• Purpose: Get trending stocks by region
• Regions: US, AU, CA, FR, DE, HK, IT, ES, GB, IN

10. Sector/Industry APIs

• Endpoint: https://query2.finance.yahoo.com/v1/finance/sector/{sector_id}
• Endpoint: https://query2.finance.yahoo.com/v1/finance/industry/{industry_id}
• Purpose: Sector and industry performance data
• Usage: Simplified sector and industry lookup/screening via SectorIndustryService

Sector/Industry API

• Sector and industry classification for a ticker via GetSectorInfoAsync(ticker)
• Sector screener via GetStocksInSectorAsync(sector, size)
• Industry screener via GetStocksInIndustryAsync(industry, size)

Facade example (showcase all methods):

var info = await client.SectorIndustry.GetSectorInfoAsync("AAPL");
var sectorStocks = await client.SectorIndustry.GetStocksInSectorAsync("Technology", size: 10);
var industryStocks = await client.SectorIndustry.GetStocksInIndustryAsync("Consumer Electronics", size: 10);

Console.WriteLine($"Sector: {info?.Sector}, Industry: {info?.Industry}");
Console.WriteLine($"Sector stocks: {sectorStocks.Count}, Industry stocks: {industryStocks.Count}");

Real-time Data APIs

11. WebSocket Streaming API

• Endpoint: wss://streamer.finance.yahoo.com/
• Purpose: Live streaming price data
• Usage: Used by WebSocket and AsyncWebSocket classes
• Protocol: Uses Yahoo's proprietary streaming protocol

12. Quote API (Real-time)

• Endpoint: https://query1.finance.yahoo.com/v7/finance/quote
• Purpose: Real-time quotes for multiple symbols
• Parameters:
  • symbols: Comma-separated ticker symbols
  • fields: Specific fields to return
• Usage: Used for real-time price updates

Additional Endpoints

13. Dividend History API

• Endpoint: https://query2.finance.yahoo.com/v8/finance/chart/{ticker}?events=div
• Purpose: Historical dividend data
• Usage: Part of historical data retrieval

14. Stock Splits API

• Endpoint: https://query2.finance.yahoo.com/v8/finance/chart/{ticker}?events=split
• Purpose: Historical stock split data
• Usage: Part of historical data retrieval

15. Mutual Fund/ETF Data API

• Endpoint: https://query2.finance.yahoo.com/v10/finance/quoteSummary/{ticker}
• Modules:
  • fundProfile: Fund-specific information
  • topHoldings: Fund's top holdings
  • bondHoldings: Bond fund holdings
  • equityHoldings: Equity fund holdings
  • bondRatings: Bond ratings distribution
  • sectorWeightings: Sector allocation
• Usage: Simplified fund/ETF access via FundDataService

Mutual Fund/ETF API

• Fund summary via GetFundSummaryAsync(ticker)
• Fund profile via GetFundProfileAsync(ticker)
• Top holdings via GetTopHoldingsAsync(ticker)
• Sector weightings via GetSectorWeightingsAsync(ticker)
• Trailing returns via GetTrailingReturnsAsync(ticker)
• Annual returns via GetAnnualReturnsAsync(ticker)

Facade example (showcase all methods):

var summary = await client.FundData.GetFundSummaryAsync("VOO");
var profile = await client.FundData.GetFundProfileAsync("VOO");
var holdings = await client.FundData.GetTopHoldingsAsync("VOO");
var sectors = await client.FundData.GetSectorWeightingsAsync("VOO");
var trailing = await client.FundData.GetTrailingReturnsAsync("VOO");
var annual = await client.FundData.GetAnnualReturnsAsync("VOO");

Console.WriteLine($"Fund: {summary?.Name}");
Console.WriteLine(profile is not null ? "Profile loaded" : "No profile data");
Console.WriteLine($"Holdings: {holdings?.Count ?? 0}, Sector weights: {sectors?.Count ?? 0}");
Console.WriteLine(trailing is not null ? "Trailing returns loaded" : "No trailing return data");
Console.WriteLine($"Annual return records: {annual?.Count ?? 0}");

16. Currency/Forex API

• Endpoint: https://query2.finance.yahoo.com/v8/finance/chart/{currency_pair}
• Purpose: Foreign exchange rates and historical data
• Usage: Used by CurrencyService for currency pairs (e.g., "EURUSD=X")

Currency/Forex API

• Current exchange rate via GetExchangeRateAsync(baseCurrency, quoteCurrency)
• Historical FX rates via GetHistoricalRatesAsync(baseCurrency, quoteCurrency, startDate, endDate, interval)
• Amount conversion helper via ConvertAsync(amount, baseCurrency, quoteCurrency)

Facade example (showcase all methods):

var quote = await client.Currency.GetExchangeRateAsync("EUR", "USD");
var history = await client.Currency.GetHistoricalRatesAsync(
  "EUR",
  "USD",
  startDate: DateTime.UtcNow.AddDays(-7),
  endDate: DateTime.UtcNow,
  interval: ChartInterval.OneDay);
var converted = await client.Currency.ConvertAsync(100, "EUR", "USD");

Console.WriteLine($"{quote?.BaseCurrency}/{quote?.QuoteCurrency}: {quote?.Rate}");
Console.WriteLine($"Historical points: {history.Count}");
Console.WriteLine($"100 EUR = {converted} USD");

17. Cryptocurrency API

• Endpoint: https://query2.finance.yahoo.com/v8/finance/chart/{crypto_symbol}
• Purpose: Cryptocurrency price data
• Usage: Used by CryptoService for crypto symbols (e.g., "BTC-USD")

Cryptocurrency API

• Current crypto quote via GetCryptoQuoteAsync(cryptoSymbol, quoteCurrency)
• Historical crypto candles via GetHistoricalPricesAsync(cryptoSymbol, quoteCurrency, startDate, endDate, interval)

Facade example (showcase all methods):

var btc = await client.Crypto.GetCryptoQuoteAsync("BTC", "USD");
var history = await client.Crypto.GetHistoricalPricesAsync("ETH", "USD", interval: ChartInterval.OneDay);

Console.WriteLine($"{btc?.Symbol}: {btc?.Price}");
Console.WriteLine($"Candles: {history.Count}");

18. Global Calendars API

• Endpoint: https://query1.finance.yahoo.com/v1/finance/visualization
• Purpose: Global event calendars for earnings, IPOs, stock splits, and economic releases
• Usage: Used by GlobalCalendarsService class

Global Calendars API

• Earnings calendar via GetEarningsCalendarAsync(start, end, limit, offset, marketCap, filterMostActive)
• IPO calendar via GetIpoCalendarAsync(start, end, limit, offset)
• Splits calendar via GetSplitsCalendarAsync(start, end, limit, offset)
• Economic events calendar via GetEconomicEventsCalendarAsync(start, end, limit, offset)
• Earnings calendar mirrors yfinance’s Calendars.get_earnings_calendar() behavior, including the optional marketCap filter and the default most-active ticker filter when offset == 0

Facade example (showcase all methods):

var earnings = await client.Calendars.GetEarningsCalendarAsync(
    start: DateTime.UtcNow.Date,
    end: DateTime.UtcNow.Date.AddDays(7),
    limit: 10,
    marketCap: 1_000_000_000,
    filterMostActive: true);

var ipos = await client.Calendars.GetIpoCalendarAsync(limit: 10);
var splits = await client.Calendars.GetSplitsCalendarAsync(limit: 10);
var economics = await client.Calendars.GetEconomicEventsCalendarAsync(limit: 10);

Console.WriteLine($"Earnings: {earnings.Count}, IPOs: {ipos.Count}");
Console.WriteLine($"Splits: {splits.Count}, Economic events: {economics.Count}");

Base URLs and Domains

• Primary Domain: query2.finance.yahoo.com (main API endpoint)
• Fallback Domain: query1.finance.yahoo.com (backup/alternative)
• Streaming Domain: streamer.finance.yahoo.com (WebSocket streaming)

Native AOT Support

CyFinance is configured for Native AOT compilation via PublishAot=true in the project file. This enables the library to be compiled into native code ahead-of-time for improved performance and reduced memory footprint. Currently, the library compiles successfully with warnings about JSON serialization that can be addressed by implementing JsonSerializerContext for full Native AOT compatibility.

NuGet Publishing (ModularPipelines)

Publishing is implemented with ModularPipelines in pipelines/CyFinance.Pipelines/Program.cs, and executed by .github/workflows/publish-nuget.yml.