Global Address and Phone Number Standards

Do not model either field as “just a string”

An address is a structured set of country-dependent components rendered through a regional template. A phone number combines a calling-code plan, national numbering metadata, and a display context. Keep the user’s original input for correction, store normalized values where appropriate, and render for the selected destination or audience rather than forcing one global layout.

Address order changes by country and script

UPU S42 separates a generic vocabulary of postal components from country-specific templates. Follow that model: store named components, then render with a maintained template for the destination country and script.

Build an adaptive, forgiving address form

Phone storage and display serve different jobs

Examples illustrate format differences and are not contact numbers or deliverability claims.

Formatting, parsing, validation, and verification are different

Parsing

Interprets digits using an explicit default country when no international calling code is present.

Formatting

Renders a parsed number as E.164, international, national, or RFC3966 output.

Validation

Checks the number against current length and numbering-plan patterns in the selected metadata bundle.

Verification

Confirms control or reachability through an SMS, voice, or another out-of-band challenge. Syntax alone cannot do this.

Parse with an explicit regional context

import { parsePhoneNumberFromString } from "libphonenumber-js";

const local = parsePhoneNumberFromString("020 7946 0018", "GB");
if (!local?.isValid()) {
  throw new Error("Check the number and selected country");
}

const record = {
  originalInput: "020 7946 0018",
  country: local.country,
  e164: local.number,
};

const nationalDisplay = local.formatNational();
const internationalDisplay = local.formatInternational();

An input such as `020 7946 0018` is ambiguous without a country. Do not guess from language, IP address, or the user’s current location when a wrong interpretation would matter; ask for or preserve the selected country.

Treat metadata as versioned operational data

• Record the source, package/data version, generation date, and covered territories.
• Schedule updates because numbering plans, postal codes, administrative divisions, and currency use change.
• When a country template is missing, collect flexible address lines instead of forcing another country’s form.
• Keep test fixtures for shared calling codes, non-geographic numbers, extensions, zero-prefix rules, territories, and script variants.
• Revalidate stored phone numbers only when required; a metadata update should not silently destroy previously accepted input.

Representative fixture matrix

const fixtures = [
  { input: "(415) 555-2671", country: "US", valid: true },
  { input: "020 7946 0018", country: "GB", valid: true },
  { input: "+81 3 1234 5678", country: undefined, valid: true },
  { input: "123", country: "US", valid: false },
];

for (const fixture of fixtures) {
  const parsed = parsePhoneNumberFromString(fixture.input, fixture.country);
  assert.equal(Boolean(parsed?.isValid()), fixture.valid);
}