In the past several years, it has no doubt become challenging to patent software inventions. However, it is still possible to obtain patents for software.
Software inventions can come in different forms. One form might be a word processing program like Microsoft Word. Another form may be a software program that controls the operation of an apparatus, such as a medical device.
A common hurdle to overcome for a software invention is that a standard general purpose computer is being used to simply gather data and then display results of the data. Another common hurdle is that the general purpose computer is being used to "computerize" a well known series of process steps in the brick and mortar world.
For software inventions (and others such as medical diagnostics), the US patent office (USPTO) continues to provide guidelines to patent examiners which describe how the examiners should determine the patentability of an invention. In legalese, this is referred to as patent eligible or ineligible subject matter.
The USPTO "2019 Revised Patent Subject Matter Eligibility Guidance" can be useful to patent applicants. The 2019 Guidance can serve as a roadmap on how to better anticipate rejections by a patent examiner to your patent application. Being able to better anticipate rejections can enable you to better draft your patent application and increase the likelihood of being awarded a patent.
Here is a condensed explanation of the 2019 Guidance as it may apply to software.
A. Is your invention an "abstract idea" such as mathematical concepts, organizing human activity, or mental processes? If NOT, then your invention contains patent eligible subject matter. But your patent application may still be rejected for other reasons, such as being obvious.
B. If your invention IS an abstract idea, is your invention integrated into a "practical application"? In other words, does your invention (i.e., patent claim) have additional elements beyond the abstract idea? The additional elements can be well-known. The additional elements can use the abstract idea in conjunction with an apparatus.
C. If your invention IS integrated into a practical application, then your invention has patent eligible subject matter.
D. If your invention is NOT integrated into a practical application, does your invention have an "inventive concept"? In other words, do the additional elements amount to "significantly more" than the abstract idea. Are the additional elements NOT well known?
E. If your invention has an inventive concept, then your invention has patent eligible subject matter. But, again, your patent application may still be rejected for other reasons, such as being obvious.