Anet Search Engine's API allows to build programs like Search32 and even more feature rich applications. It is royalty free, you can develop any number of applications and distribute unlimited copies without distribution fees. Read a bit more about ASE API
Another option for developers is to use the Search32 utility API. This API may be used if you distribute Search32 with your application. The Search32 API is similar to Anet Search Engine API (ASE API), but includes only functions to send queries and receive search results. The indexes will be created by running Search32 itself. The user can then conduct searches with your application. It is not necessary to load the Search32 utility when the user works with index files from within your application.
To use the Search32 API you must purchase a Search32 utility licenses for each copy of your application you are going to distribute. For example if you want to produce 100 CD-Roms with your application using Search32 functions you will need to purchase 100 Search32 licenses even if you keep it on CD-Rom and even though your application does not require installation on a personal computer.
You must distribute Search32 utility as a product without decompiling and extracting separate components of Search32. In order to use Search32 API you need to buy at least 3 licenses for $99.00If you want to buy from 3 to 10 licenses - the cost will be $270.00
Starting from version 4.05 Search32 can be used on CD-Roms. In order to do that you should send us your request and inform how many CD-Roms with Search32 you are going to release. After short negotiations about the price we will send you a special password which must be used one time at very first search in the CD-Rom on every personal computer, where this disc will be used.
Download Search32 version 4x from s32e4x.exe