Altmetrics are alternative metrics for measuring the impact of scholarly work that use social media and online mentions. They provide a more comprehensive view of impact across different sectors. Altmetric tools track how often research is mentioned online, including the number of tweets, likes, shares and saves. This provides a more timely measure of impact than traditional citations alone. While altmetrics don't tell the whole story, they can help understand broader impacts beyond academia. Librarians can help researchers understand and use altmetrics to track engagement and influence.