This paper studies the impact of generative artificial intelligence (AI) technologies on the demand for online freelancers using a large data set from a leading global freelancing platform. We identify the types of jobs that are more affected by generative AI and quantify the magnitude of the heterogeneous impact. Our findings indicate a 21% decrease in the number of job posts for automation-prone jobs related to writing and coding compared with jobs requiring manual-intensive skills within eight months after the introduction of ChatGPT. We show that the reduction in the number of job posts increases competition among freelancers, whereas the remaining automation-prone jobs are of greater complexity and offer higher pay. We also find that the introduction of image-generating AI technologies led to a 17% decrease in the number of job posts related to image creation. We use Google Trends to show that the more pronounced decline in the demand for freelancers within automation-prone jobs correlates with their higher public awareness of ChatGPT’s substitutability.