The openFDA API supports searching by range in date, numeric, or string fields.

• Specify an inclusive range by using square brackets [min+TO+max]. These include the values in the range. For example, [1+TO+5] will match 1 through 5.
• Dates are simple to search by via range. For instance, [2004-01-01+TO+2005-01-01] will search for records between Jan 1, 2004 and Jan 1, 2005.