Validation of user journeys can vary depending on your objectives, resources, and constraints. User testing is a popular option; you can ask real or potential users to perform tasks and observe their behavior while using prototypes, mockups, or live products. Surveys, interviews, and analytics can help measure the results. User research is also beneficial, as you can use surveys, interviews, focus groups, or ethnographic studies to collect qualitative and quantitative information. Personas, scenarios, and empathy maps can help synthesize and analyze the data. Expert review is another useful approach; heuristic evaluation, cognitive walkthroughs, and usability inspections can assess the quality and usability of user journeys. Checklists, ratings, and comments can be used to document and communicate feedback.