Real-time validation (used at the point of capture):
Real-time number validation is needed when your customer onboarding is sensitive to experience any potential friction. It is also often needed when sending one-time passwords (OTP), when fraud risk is high, or immediate corrections are required.
When validating numbers in real-time, it more often leads to higher conversions, a reduction in support tickets and less fraud.
Batch validation (for existing databases)
Batch number validation is required for tasks including historical CRM clean-ups, in readiness for a campaign, or perhaps a business may need to clean up their data before migrating tools.
A batch validation will lead to a reduction in wasted send costs, deeper segmentation of contacts, and cleaner (more reliable) reporting.
Most businesses require both to complement their needs: real-time to prevent new problems, batch to fix existing ones.