The EndoFLIP (for its acronym in English: endoluminal functional luminal probe) is a system that measures in real time the compliance index of the gastroesophageal junction and secondary esophageal peristalsis, based on the principle of impedance planimetry. Although this technology is relatively new and its diagnostic usefulness is still being evaluated, its use in clinical practice is increasingly recognized, fundamentally in those patients where there is no conclusive manometric diagnosis of esophageal motor pathology, mainly esophagogastric junction outflow obstruction and achalasia.