Topic 01 of 07
Address validation
Check whether an address is structurally complete and plausible before you treat it as deliverable.
Why it matters
Validation is usually the first gate. It catches missing components, impossible postal codes, and malformed strings so downstream verification and mailing spend less on bad records.
What validation actually checks
Validation asks: does this string look like an address? Are required parts present (street, locality, region, postal code)? Do formats match expected patterns for the country?
It does not always prove a carrier can deliver there. A perfectly formatted address can still point to a vacant lot, a demolished building, or a non-existent unit.
Common techniques
Rule-based parsers split free-text into components (house number, street name, unit, city, state, ZIP).
Country-specific schemas enforce local conventions—US ZIP+4 shapes differ from UK postcodes or Canadian FSA+LDU formats.
Lightweight API checks can confirm postal-code–to-city consistency without a full postal-authority lookup.
When validation is enough
Internal directories, CRM hygiene passes, and form UX often start with validation alone.
If you mail, ship, or bill against an address, pair validation with verification (and often CASS or equivalent certification for US bulk mail).
Related topics
- Address verification→
Confirm that an address exists in authoritative reference data and can typically receive mail or deliveries.
- Standardization & formatting→
Rewrite addresses into a consistent, preferred format so systems can compare, store, and print them reliably.
- CASS certification→
USPS Coding Accuracy Support System—software certification and a process that improves ZIP+4 and delivery-point accuracy for US mail.