GPR35 is a class A G protein-coupled receptor (GPCR) implicated in various physiological and pathological processes, including metabolic regulation, immune response, and cancer progression. Initially identified as an orphan receptor, GPR35 is activated by endogenous ligands such as kynurenic acid and exogenous compounds like zaprinast. It is highly expressed in the gastrointestinal tract, immune cells, and certain cancers, suggesting roles in inflammation, pain signaling, and tumor microenvironment modulation. Antibodies targeting GPR35 are essential tools for studying its expression patterns, signaling mechanisms, and therapeutic potential. However, developing specific GPR35 antibodies has been challenging due to low receptor abundance, sequence homology with other GPCRs, and limited immunogenic epitopes. Polyclonal and monoclonal antibodies are commonly used in techniques like Western blotting, immunohistochemistry, and flow cytometry to validate tissue distribution or receptor activation states. Recent studies highlight GPR35's involvement in diseases like inflammatory bowel disease, diabetes, and colorectal cancer, driving demand for reliable antibodies to explore its diagnostic or therapeutic relevance. Proper validation using knockout controls or functional assays remains critical to ensure antibody specificity, as off-target binding can compromise data interpretation. Ongoing research aims to refine antibody design and uncover GPR35's complex roles in health and disease.