• Investigating the pace of AI innovations has thus become increasingly relevant. Yet, few studies have managed to measure or depict this increasing velocity of innovations in AI. • A research framework and three measures, i.e., Average Time Interval (ATI), Innovation Speed (IS), and Update Speed (US), are proposed, to explore the pace of AI from the perspective of AI papers, AI players, and trial and error. The fine-grained analysis of the AI field enabled to portrait the pace of AI innovation and demonstrated that the proposed approach can be adopted to understand other fast-growing fields. • In 2019, more than 3 AI preprints were submitted to arXiv per hour, over 148 times faster than in 1994. Furthermore, there was one deep learning–related preprint submitted to arXiv every 0.87 hours in 2019, over 1,064 times faster than in 1994. • 5.26 new researchers entered into the field of AI each hour in 2019, more than 175 times faster than in the 1990s. • An updated version of the AI preprint was submitted to arXiv every 41 days, with around 33% of arXiv’s AI preprints being updated twice or more in 2019. It took about 0.2 year on average for AI preprints to get their first citations from 2014–2019, around 5 times faster than from 2000–2007. Innovations in artificial intelligence (AI) are occurring at speeds faster than ever witnessed before. However, few studies have managed to measure or depict this increasing velocity of innovations in the field of AI. In this paper, we combine data on AI from arXiv and Semantic Scholar to explore the pace of AI innovations from three perspectives: AI publications, AI players, and AI updates (trial and error). A research framework and three novel indicators, Average Time Interval (ATI), Innovation Speed (IS) and Update Speed (US), are proposed to measure the pace of innovations in the field of AI. The results show that: (1) in 2019, more than 3 AI preprints were submitted to arXiv per hour, over 148 times faster than in 1994. Furthermore, there was one deep learning–related preprint submitted to arXiv every 0.87 h in 2019, over 1064 times faster than in 1994. (2) For AI players, 5.26 new researchers entered into the field of AI each hour in 2019, more than 175 times faster than in the 1990s. (3) As for AI updates (trial and error), one updated AI preprint was submitted to arXiv every 41 days, with around 33 % of AI preprints having been updated at least twice in 2019. In addition, as reported in 2019, it took, on average, only around 0.2 year for AI preprints to receive their first citations, which is 5 times faster than 2000–2007. This swift pace in AI illustrates the increase in popularity of AI innovation. The systematic and fine-grained analysis of the AI field enabled to portrait the pace of AI innovation and demonstrated that the proposed approach can be adopted to understand other fast-growing fields such as cancer research and nano science.