On the first of august 2012, Microsoft stopped returning results to all the BING Search API v 2.0 requests. This was an intentional and announced change, which is a part of their migration to the new and metered BING Search API (Azure).
In the new API, youre still allowed to search for free if you stay under 5000 search requests/transactions per month if you need an API key that can do more than 5000 transactions per month, here is the pricing table:
|5 000||€ 0.00|
|10 000||€ 15.31|
|20 000||€ 30.61|
|50 000||€ 76.53|
|100 000||€ 153.06|
|250 000||€ 382.65|
|500 000||€ 765.30|
|1 000 000||€ 1 530.60|
|1 500 000||€ 2 295.90|
|2 000 000||€ 3 061.20|
|2 500 000||€ 3 826.50|
This is the pricing table displayed in Belgium on the 6th of august 2012, using a point as the decimal sign.
As the implementation of the API on my website could easily pass 5 000 transactions per month, I had to rethink the way I was using it. I noticed that the API was requesting some content several times so I have solved my transaction limit issue by caching results. Caching results is allowed under the second section of the BING Search API (Azure).
The caching is easily achieved by storing the previously searched terms together with a timestamp. Depending on how long you want to keep displaying the cached version of the content, you can look at the timestamp and determine when you want to get a new version of the content using the API. I myself made sure to cache all the content on my website, before Microsoft turned off the BING Search API v 2.0 switch, and will be looking at updating the content in the future using the Azure version of the API.
As the caching used between 250 000 and 500 000 transactions (in one day), if the caching were to re-run, the transactions under the paid model would have cost me 765.30 instead of the 0 it was at the time.
Section 2 of the user agreement for BING Search API (Azure).
2. WHAT RIGHTS DO I HAVE? Solely to the extent that you are in compliance with all terms of this Agreement, we grant you a non-exclusive, non-transferable, non-sublicenseable license to use the Services to: enable your Website or application to obtain Bing results; make limited intermediate copies of the Bing results, solely as necessary to display or use them as a part of your Website or application; or host and display Bing results on your Website or application. Your license to use the Services is limited, however, to solely your Websites and applications. You are responsible for your own conduct and content while using the Services and for any consequences of this use.