This chapter examines the evolution and current landscape of independent fact-checking as an ex post response to disinformation. It traces the historical roots of fact-checking from traditional editorial practices to the emergence of contemporary initiatives aimed at verifying content already in circulation. The modern fact-checking movement underwent a significant expansion after 2016, driven by the global debate over “fake news” and political disinformation, particularly on social media platforms. The field has always been diversified in scope and structure, encompassing projects that target both political and non-political misinformation. These initiatives vary in size, funding, and organizational models, with growing efforts toward institutionalization through international networks like the IFCN, EFCSN, and EDMO. Since its inception, fact-checking faces critiques regarding its epistemological assumptions, limited effectiveness in changing beliefs, and potential biases. Nonetheless, it remains a crucial tool for providing context and transparency in public discourse, even as it contends with financial pressures, political hostility, and the evolving challenges of the digital information ecosystem.