A Facebook UID (User ID) is a unique numerical identifier assigned to every Facebook profile, page, group, or post. Checking UIDs helps you:

• Filter out active (live) UIDs for targeted advertising
• Avoid wasting money on ads targeting dead profiles
• Improve accuracy in retargeting and engagement campaigns
• Maintain account safety and reduce spam risks

Legal Reminder: Use legitimate and authorized UID lists only. Do not spam or violate Facebook's Terms of Service. Respect users' privacy and avoid misuse of personal data. This tool is for ethical marketing and data optimization only.