How to format an international phone number (E.164, +country, no dashes)

Every reliable click-to-chat link — wa.me, viber://, signal.me, t.me, zalo.me — expects a phone number in the same format: E.164. If you hand a link the number in the wrong shape, it silently fails. This is the #1 reason people say "the link didn't work."

What E.164 is

E.164 is the ITU's international numbering standard. A conforming number is:

Up to 15 digits total (including country code).
Country code first (1 to 3 digits).
Optionally prefixed with +.
No spaces, no dashes, no parentheses, no dots.

Examples:

UK mobile: +447700900123
US mobile: +14155552671
Hong Kong mobile: +85298765432
India mobile: +919876543210
Brazil mobile: +5511987654321

The plus sign: sometimes yes, sometimes no

Different link formats disagree on whether the plus sign belongs:

wa.me/ — no plus sign. wa.me/85298765432.
viber://chat?number= — plus sign required. viber://chat?number=+85298765432.
signal.me/#p/ — plus sign required.
zalo.me/ — no plus sign.
tel: (dial pad) — plus sign optional but strongly recommended for international dialing.

Ringlink handles this for you. Internally we always store numbers in E.164 with the plus sign, and format per-link at launch time.

The trunk prefix trap

Most countries have a "trunk prefix" — a leading digit or two you dial for domestic calls but drop for international. This is where users get it wrong most often:

UK: domestic 07700 900123 → international +44 7700 900123. Drop the leading 0.
France: 06 12 34 56 78 → +33 6 12 34 56 78. Drop the 0.
Germany: 0171 1234567 → +49 171 1234567. Drop the 0.
Russia: 8 (925) 123-45-67 → +7 925 123 45 67. Drop the 8, add +7.
Italy: 333 1234567 → +39 333 1234567. Keep the leading digit — Italy doesn't use trunk zeros for mobiles.

North American Numbering Plan (NANP)

The US, Canada, most of the Caribbean, and some Pacific territories all share country code +1. Numbers look like area-code + 7 digits: +14155552671. There's no trunk prefix to drop — the "1" you dial for long distance IS the country code.

Special numbers to avoid in links

Toll-free numbers (US 800, UK 0800, etc.) — many don't route from outside the country. Don't put them in international WhatsApp links.
Short codes — 4–6 digit codes used for SMS services (like 32665 for Facebook). Not phone numbers; won't work in any messenger link.
Premium-rate numbers — often can't receive messages at all.

How to test a number quickly

Type it into Ringlink with the country flag picked.
If Ringlink accepts it, it's E.164-valid.
If a messenger tile fails to open, the specific app doesn't have that number registered — but the format is right.

Storing numbers programmatically

If you're building a system that will eventually feed into messenger links, always store numbers as E.164 strings with the plus sign. Every mainstream phone-number library (Google's libphonenumber, the many JavaScript ports) accepts E.164 as input and can format it for display. Store canonical; format for humans; never the other way around.