Yahoo! Developer Network - Frequently Asked Questions

Here is a list of the questions we get asked most frequently, with their answers. If you don't find an answer to your question, please contact us.

Yahoo! Web Services and APIs

Q: What are Yahoo! Web Services and APIs?

Web Services provide application developers access to content and services to build new applications. For example, you can combine our data and services with those you create in a desktop application or those offered by other Web sites. With Yahoo! Web Services, more of the power of the Yahoo! network is in your hands.

Q. Who are Yahoo! Web Services and APIs for?

Yahoo! Web Services are for developers, businesses, and researchers interested in using Yahoo! products, services, data, and content as a resource in their applications. Currently, this program is free, not subject to any SLA or uptime agreement, and subject to daily limits on query volume. If your requirements are above and beyond our standard non-commercial usage policies, please contact us and tell us how we can help your business grow.

Q: What do I need to access Yahoo! APIs?

To access Yahoo! Web Services, we require that you register and use an API Key (sometimes referred to as application ID), which is tied to your application. Your application ID must be sent with each Web Services request. Your application must also follow our Usage Policy.

Q: What is an Application ID?

As noted in the preceding answer, an Application ID is a string that uniquely identifies your application. Think of it like a User-Agent string. If you have multiple applications, you must use a different ID for each one. Get yours here.

Q: What is REST?

REST stands for Representational State Transfer. Most of the Yahoo! Web Services use "REST-Like" RPC-style operations over HTTP GET or POST requests with parameters URL encoded into the request.

For more information about REST, you can start with the following:

Q: What programming languages does Yahoo! support?

You can use any language you like.

Q: Where can I get help on using Yahoo! Web Services and APIs? Where do I report bugs or outages?

The best way to report bugs, outages, or unexpected behavior is by posting to the developer support forum for the Web Service or API in question.

Limitations and Commercial Use

Q: What are the guidelines and limitations for applications using Yahoo! Web Services and APIs?

All of our Web Services are available for use up to the standard per-service rate limit in applications and Web sites that comply with our Terms of Use. Many of our Web Services will allow certain kinds of business usage, but this can vary per-service. You can review our general Usage Policies for more information about what is permitted.

Q: Does it cost anything to use Yahoo! Web Services and APIs?

No. We do not charge for access to our Web Services. We make them available for free to you as-is, rate limited, and controlled by the relevant Terms of Use. We will be providing more commercial terms going forward. You may use the services up to their individual standard daily rate limit (see the documentation for specifics) in applications that comply with our Usage Policies.

Q: What are the limits on how much I can use Yahoo! Web Services?

Access is rate-limited based on the caller's IP address, and queries are limited per IP and per day. Each service may have a different access rate limit. See the documentation for each service for more information. Circumvention of these rate limits by any means is expressly forbidden under our Terms of Use .

Q: How will I know when I hit the daily limit?

When a rate limit has been exceeded, the HTTP request will receive an error code of 403, along with a standard XML error response. See our rate limiting documentation for details.

Q: How do I request additional queries?

You can request additional queries for your application via this form.

Q: What is the limit on the number of results I can receive per query?

Each service may have different limits on the number of results returned by each query, as well as other variations in supported parameters. The documentation for each service specifies the default number and maximum number you can receive.

Q: Some of your services say "non-commercial use only." What does that mean?

Some of our services are made available only for use in non-commercial applications. For those services, we are not able to place firm limits on what we consider "commercial use" because so many unforeseen uses are invented daily that we need to maintain a level of flexibility — especially while the program is free. That said, the following general examples show uses we consider to be commercial:

  • Use of our services on high traffic, established commercial-oriented or business web sites or applications
  • Applications or web sites monetized indirectly (by advertising, affiliate links) or directly, including subscriber-only content (subscriptions, software-as-a-service, hosted applications where your users pay for access) and for-pay applications, products, or services
  • Productivity tools for businesses created to bring value to a business function, typically only accessible to select users

Developers can create applications that use our APIs and web services as work-for-hire for clients; however, the usage within the application itself must be approved.

User Data Usage

How does Yahoo! define user data?

Generally, any information in relation to a Yahoo! user is considered user data - this includes account information, observed activities, data shared by the user through a Yahoo! API, or any derived or inferred information that extends from this sharing. Please refer to the Yahoo! APIs' Terms of Use, associated guidelines, and this FAQ to better understand your rights and responsibilities when handling Yahoo! user data.

How do users give permission for sharing user data with third parties?

To provide permission for the use of non-public user data, a user must provide consent to the third party (for example, through OAuth): A user is presented with a consent-flow interface when asked to share data with a third party through a Yahoo! API. This interface informs users of what information about them and their activities will be shared with the third party. Users have the option to retract this permission at any time by visiting their Manage Account page.

In general, the use of public user data, such as through the Updates Firehose API, does not need explicit user consent. Users are able to control what data is made public via the Manage Updates area of Yahoo! Pulse or at the location where they post an update on Yahoo!.

Can user data be cached or stored, and for how long a period of time?

In general, user data may be stored and cached for up to 24 hours but there are types of user data that may be stored or cached for longer periods of time. In particular, if you are caching sign-on through OAuth, the Authenticated Token Value may be stored indefinitely (unless or until it is revoked). Pursuant to the restrictions outlined in the Yahoo! Developer Network Guidelines, Updates also may be stored indefinitely, unless a user or Yahoo! requests deletion. Please refer to the Yahoo! APIs Terms of Use, associated guidelines, and these FAQ for more information.

Under what circumstances can user data be displayed offline?

In general, user data may only be used on a website and/or within a mobile device application.

Can user data obtained through interaction with my App be used commercially?

Yes, if the API from which you obtained the data allows commercial usage, user data obtained through interaction with your App may be used commercially but is subject to the rate limit as discussed in the Yahoo! APIs Terms of Use, associated guidelines, and documentation.

Can a user control whether his/her data is used for commercial purposes?

Yes, a user can control whether or not to make his/her data public, but once a user gives permission to share data with the developer, the developer controls what is done with the user's data. If the developer chooses to store user data for longer than 24 hours, it must post a privacy policy that explains what user data is collected and the uses of that data. The privacy policy must be accessible from the developer's App and it must provide a way for users to request deletion of their data. If a user does request deletion of user data, the developer must comply within 24 hours. Note: Not all Yahoo! APIs allow commercial usage. Please refer to the Yahoo! Developer Network Guidelines for more information.

Can user data be sold to a third party?

No. Selling user data to a third party is in violation of the Yahoo! APIs Terms of Use. In the event of a violation of the Terms of Use, your developer's license to use the Yahoo! APIs may be revoked.