Requirements

 Use of the API requires a Factual API key and the ability to issue requests to http://api.factual.com from your server or client-side script.

API Keys

Factual API keys can be obtained at the developer section of Factual.com -  http://www.factual.com/developers.

Factual API keys come in two forms:

• Read Keys
  • Read keys provide read-only access to Factual data and state information.  Read keys can be used in both server-side and client-side code.
• Write Keys
  • Write keys provide read and write access to Factual data and state information.  Write keys should be reserved for back-end/server code.  You should avoid making these publicly viewable as they can be used to update information with the privileges of and attributed to the linked account.

Response Formats

• JSON*
• XML
• In some situations, we expose additional formats for specific features

*For JSON data, you can include an optional JSONP callback by adding 'jsoncallback=mycallback' to your query(e.g. /read?jsoncallback=?)

Result Object 

All responses from the API will be packaged in a Result object.  This object provides the result payload as well as status and error information. 

• status
  • ok
  • warn
  • error
• message (blank if ok)
• processing time (ms; verbose mode only)

Support

The best line of defense to get a question answered is to post in the Factual Developer Google Group - http://groups.google.com/group/factual_developers.  In fact, even before you post it you should search around and make sure that the question has not come up before.

If you are not getting an answer there, please use our developer email address - developer@factual.com.  Depending on our influx of emails and how polite you are, we'll get back to you sooner or later.