BBAuth

Registered Yahoo! users can sign on for your services without having to complete yet another registration process.

OpenID

Easy delivery of a simplified login experience for your users.

Address Book

Access and update contacts in the Yahoo! Address Book.

Mail

Build applications to list messages, display folders, compose and send messages.

Messenger

Create add-ons with collaborative features that can run inside Yahoo! Messenger.

Finance

RSS feeds deliver timely data on finance topics including top stories, most viewed, and company ticker symbol.

HotJobs

Post, edit, refresh and delete public and private job ads. Use the API to manage your job ads in real-time.

Kelkoo

Create applications that provide comparison shopping and product search functionality.

MyBlogLog

Build social networking services on demand. Create badges and access user activity data.

Shopping

Access millions of product listings and thousands of merchants.

RSS Feeds

Content for a variety of products and services – thousands of feeds in total.

Travel

Build applications that allow trip planning and sharing, airfare comparisons, and ratings and reviews.

Upcoming

Add user-generated event and location data to your applications and websites.

Fire Eagle

Create location-aware applications and services.

GeoPlanet

A resource for managing all geo-permanent named places on Earth.

Local

Bring location-based information and user-created content to your website.

Maps

Flash, Ajax and Map Image APIs allow embedding of rich, interactive maps.

TagMap

TagMaps is a toolkit to visualize text (well, tags) geographically on a map.

Traffic

Access real-time traffic alert information for a given location.

Weather

Get up-to-date weather information for your location.

Zonetag

ZoneTag is a research prototype release from Yahoo! Research Berkeley that allows cell tower to location mapping.

Flickr

Tap into this highly interactive photosharing community that uploads and shares photos and tags.

Live Video Broadcast

Create your own broadcast channel, or display, hack, and mash up live video streams on your website or client.

Media Player

Create an embedded player for each audio link on your site, or, with one click, turn any page into a playlist.

Music API

Get access to the Yahoo! Music catalog of artists, albums, tracks, videos, ratings and more

Answers

Provide user-generated advice on any topic, from within your own site.

BOSS

BOSS (Build your Own Search Service) is Yahoo!'s open search web services platform for the next generation of search innovation, serving hundreds of millions of users across the Web.

delicious

Search delicious bookmarks and tags or see when a specific user last posted.

Search Monkey

Reach tens of millions of Yahoo! Search users by using structured data to enhance your Yahoo! Search results and make them more useful, relevant, and visually appealing.

Y! Search Marketing

Create and manage campaigns, pull reports, set bids and more. These capabilities are exposed via a collection of SOAP-based Web Services.

Y! Search SDK

Libraries and sample code for accessing Yahoo! Search Web Service APIs from various languages, including Flash, Java, PHP, Ruby, Python, Perl, JavaScript, C#, VB and .Net.

Y! Search Web Services

Access data from the wide variety of web and vertical search content available via Yahoo!, including Audio, News, Site, Image, Web and Local search content.

Konfabulator Widgets

Tools to help build self-contained desktop Widgets.

l10n & i18n Tools

Tools that make it easy to set up templates and translate your website.

Mobile Widgets

Build Mobile widgets with a standards-based language, easy-to-use toolkit, and a seamless path to hundreds of devices.

Network Time

Little helpers for applications that consume web services.

Pipes

A powerful composition tool to aggregate, manipulate, and mashup content from around the web.

ColdFusion

Flash

Java

JavaScript

.NET

PHP

Python

Ruby

Silverlight