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phone-number-validator

A phone number validator parses a phone string under a chosen country's rules, normalizes it to E.164 international format (+countrycode followed by digits), classifies it as mobile / fixed-line / VoIP / toll-free / premium-rate, and detects obvious errors like wrong digit counts or invalid prefixes — using Google's libphonenumber rules so the verdict matches what carriers actually deliver. The ZTools Phone Validator runs entirely in the browser, supports 200+ countries, validates bulk lists up to 1,000 entries at once, exports labelled CSV / JSON, and exposes country-specific format hints so users see why a number was rejected and how to fix it.

Use cases​

Form input validation​

Sign-up forms ask for phone. Validate against the user's declared country; offer country-specific error messages.

CRM list cleanup​

Sales lists accumulate sloppy phone formats. Bulk-validate and emit clean E.164 strings for telephony / SMS APIs.

SMS pre-flight check​

Before sending SMS at scale, dedupe and normalise phone numbers. Invalid ones cost money and never deliver.

Lead-form quality scoring​

Lead with valid mobile + valid email + matched country = high-quality. Validator output feeds a scoring rule.

How it works​

  1. Pick the default country — Affects how leading digits are interpreted (e.g. "020 ..." parses as UK landline given GB default).
  2. Paste number(s) — Single or bulk. Both spaces and dashes acceptable; the parser strips formatting.
  3. Parse and validate — libphonenumber rules return: valid yes/no, country, line type, E.164 form, national display form.
  4. Inspect line type — mobile, fixed_line, voip, toll_free, premium_rate, shared_cost, unknown.
  5. Export — CSV with: input, valid, country, line_type, e164, national_format. JSON also available.

Examples​

Input: +1 415 555 0123 (US)

Output: valid=true, country=US, line=mobile, e164=+14155550123

Input: 020 7946 0958 (GB default)

Output: valid=true, country=GB, line=fixed_line, e164=+442079460958

Input: 0800 123456 (DE default)

Output: valid=true, country=DE, line=toll_free

Frequently asked questions​

What is E.164?

The international phone-number format: + then country code then national number. Maximum 15 digits. SMS / VoIP APIs require E.164 — non-E.164 input often silently fails.

Can it tell mobile from landline?

For most countries yes — libphonenumber maintains range databases. Some countries have ported numbers (mobile to landline), so the verdict is "intended type at allocation", not necessarily "current type".

Why is "555-0100" invalid?

In North America, 555-01xx is reserved for fictional use (TV / movies). Real assignments do not use that range. The validator correctly flags it as invalid.

Does it call the number?

No — pure offline rule-based parsing. No tariffs, no API calls, no live dial.

What about VoIP numbers?

Detected when the country exposes VoIP ranges (US tollfree, UK 070, etc.). For most countries the verdict is "fixed_line_or_mobile" because the data is not segmented.

Are international roaming numbers handled?

Roaming uses the home E.164. The validator returns the home country regardless of where the device is currently connected.

Tips​

  • Always validate at form-submit AND before any SMS API call — formats drift between the two.
  • For multi-country forms, capture country first, then phone — the parser is dramatically more accurate with a default country.
  • Use E.164 as the canonical form in your database; render national format only for display.
  • Reject premium-rate and unknown line types on signup forms — they are usually fraud-prone.
  • When users mistype, show the country-specific format hint instead of a generic "invalid phone".

Try it now​

The full phone-number-validator runs in your browser at https://ztools.zaions.com/phone-number-validator — no signup, no upload, no data leaves your device.

Open the tool ↗

Last updated: 2026-05-05 · Author: Ahsan Mahmood · Edit this page on GitHub