Global Validation Data Coverage

“Global” is not one coverage level

A provider can accept requests worldwide while offering rooftop-level reference data in one country, locality-level correction in another, and formatting-only behavior elsewhere. Coverage must be evaluated by country, script, endpoint, and required outcome—not by the size of a marketing number.

Formatting, validation, deliverability, and geocoding

Provider documentation comparison

This table compares how the providers' own documentation exposes coverage. It is not a universal ranking: products, licensed datasets, pricing, and country support change, so verify the current contract and run the same test corpus against each candidate.

A vendor scorecard that survives a sales demo

Score each launch country independently. Require evidence for the endpoint and commercial tier you will actually use.

1. Reference provenance: postal authority, government, commercial, map, user-contributed, or blended data; update cadence and effective date.
2. Granularity: country, administrative area, locality, postcode, street, premise, subpremise, delivery point, or rooftop.
3. Scripts and languages: native-script input/output, Latin transliteration, aliases, accents, and mixed-script behavior.
4. Correction evidence: which fields were confirmed, corrected, inferred, unconfirmed, or replaced; confidence and ambiguity signals.
5. Operational evidence: postal deliverability signals, geocode precision, residence/business classification, and known exclusions.
6. Integration: latency, batch and interactive endpoints, rate limits, deterministic IDs, retention, privacy, and permitted caching.
7. Failure policy: behavior for ambiguous, rural, new-build, PO box, military, and unsupported addresses.

Country-specific cases your test corpus needs

Examples describe test dimensions, not current allocation or deliverability guarantees. Validate real test fixtures against the relevant authority and current provider documentation.

Phone-number validation has four separate questions

1. Parseable: can the text be interpreted with a region and current numbering-plan metadata?
2. Possible: does its length and structure fit a known plan?
3. Valid range: does the prefix match a currently assigned pattern in the metadata?
4. Reachable and controlled: can an OTP or call reach it, and can the user complete the challenge?

import { parsePhoneNumberFromString } from "libphonenumber-js";

const parsed = parsePhoneNumberFromString("020 7946 0018", "GB");

const result = {
  parseable: Boolean(parsed),
  possible: parsed?.isPossible() ?? false,
  metadataValid: parsed?.isValid() ?? false,
  e164: parsed?.number ?? null,
  // Set only after a separate verification challenge succeeds.
  ownershipVerifiedAt: null,
};

// Metadata validity does not prove that the number is assigned or reachable.

Keep evidence, not just a boolean

A single valid: true cannot explain what changed or how much the provider knew. Store normalized fields, field-level verdicts, precision, provider, dataset/result version, and the user-confirmed original where policy allows.

{
  "inputId": "checkout-address-2",
  "country": "JP",
  "provider": "selected-provider",
  "checkedAt": "2026-08-02T12:00:00Z",
  "datasetVersion": "provider-reported-version",
  "outcome": "confirmed-with-correction",
  "correctedFields": ["postalCode", "administrativeArea"],
  "unconfirmedFields": ["subpremise"],
  "geocodePrecision": "premise",
  "deliverabilityEvidence": "not-assessed",
  "userAcceptedCorrection": true
}

Run a measured proof of coverage

1. Define launch countries, required scripts, expected address types, and success criteria.
2. Build a consented or synthetic gold dataset containing valid, invalid, incomplete, ambiguous, rural, PO box, and subpremise cases.
3. Send identical cases to each provider endpoint and preserve raw verdicts.
4. Measure false correction, false rejection, unresolved ambiguity, field recovery, latency, and unit cost per country.
5. Have in-country reviewers inspect standardized output and operational usability.
6. Set country-specific fallbacks: accept as entered, ask a targeted question, switch provider, or route to manual review.
7. Repeat after material reference-data, API, or numbering-plan updates.