Here’s a description of `de.finance.yahoo.com/d/quotes.csv` suitable for use in a webpage, written in HTML:

Yahoo Finance CSV Quotes API (Deprecated)

Please Note: This API is no longer officially supported by Yahoo Finance. While it may still function, its reliability and availability are not guaranteed. It is highly recommended to explore alternative data sources and APIs.

The URL de.finance.yahoo.com/d/quotes.csv (or similar URLs using other regional domains like `en.finance.yahoo.com`) historically provided a simple way to retrieve stock quotes and financial data in CSV (Comma Separated Values) format. This service was widely used by developers and financial enthusiasts for scripting, data analysis, and building custom applications.

How It Worked

The basic principle was to construct a URL with specific parameters telling the API which stock symbols to retrieve data for and which data fields (e.g., price, volume, change) to include in the response. The API would then return a CSV file containing the requested information.

The core components of the URL were:

Base URL: de.finance.yahoo.com/d/quotes.csv
Symbol Parameter: ?s= followed by one or more stock symbols separated by commas (e.g., ?s=AAPL,GOOG,MSFT).
Format Parameter: &f= followed by a string of characters, each representing a different data field. The order of these characters determined the order of the columns in the CSV output.

Example URL (Likely Non-Functional)

de.finance.yahoo.com/d/quotes.csv?s=AAPL,GOOG&f=sl1d1t1c1ohg

In this example:

s=AAPL,GOOG requested data for Apple (AAPL) and Google (GOOG).
f=sl1d1t1c1ohg specified the following fields:
- s: Symbol
- l1: Last Trade Price
- d1: Last Trade Date
- t1: Last Trade Time
- c1: Change
- o: Open
- h: Day’s High
- g: Day’s Low

Data Field Codes

A comprehensive list of field codes existed, but was never officially documented by Yahoo. Users relied on community-maintained lists to understand which codes corresponded to which data fields. Commonly used codes included those listed above, plus volume (v), bid (b), ask (a), previous close (p), and many more.

Limitations and Alternatives

This CSV API was simple but had limitations:

No Official Documentation: The lack of official documentation made it difficult to rely on and understand the API’s behavior.
Unreliable: Yahoo could change or discontinue the API without notice.
Rate Limiting: There was often undocumented rate limiting, which could cause requests to fail if too many were made in a short period.

Due to these limitations and its deprecated status, it’s crucial to explore alternative data sources such as the Yahoo Query Language (YQL) (also deprecated) or other commercial data providers like Alpha Vantage, IEX Cloud, or Finnhub. These services typically offer more robust and reliable APIs with better documentation and support, though often require registration and may involve costs.