International Business Machines Corp. showed off its artificial intelligence software this week for use as a foundation for programmers, as it welcomed about 1,300 software developers to the first Watson Developer Conference in San Francisco.

Watson in 2011 famously beat human contestants on the television game show “Jeopardy,” and IBM went on to apply the technology to helping doctors diagnose and treat cancer. Since then, the technology has evolved into a collection of software that dispenses human-like conversation, vision,...