Input guide
How to format a phone number in E.164
E.164 is the international phone-number format used by TG Validator requests. A normalized identifier begins with +, includes the country calling code, contains digits only after the plus sign, and does not include spaces, brackets, or a domestic trunk prefix.
Reviewed July 21, 2026
What is a valid E.164 input?
Use + followed by the country calling code and subscriber number, with no spaces or punctuation—for example, +14155552671. Do not simply prepend a calling code to an unchanged local number: remove display formatting and any domestic-only trunk prefix according to that country's numbering rules.
Normalize the number before verification
Preserve the original value for audit, then build one canonical identifier for matching and API requests.
- 1
Determine the country
Use an explicit country field or reliable source context rather than guessing from an ambiguous local number.
- 2
Remove presentation characters
Delete spaces, hyphens, parentheses, and dots; they are not part of the normalized identifier.
- 3
Apply national numbering rules
Remove a domestic trunk prefix only when the country's numbering plan requires it in international form.
- 4
Add + and the calling code
Validate the resulting canonical string before sending service_type=tg.
Examples and common corrections
These examples demonstrate common patterns and do not replace an up-to-date numbering-plan library.
| Input | Normalized example | Reason |
|---|---|---|
| +1 (415) 555-2671 | +14155552671 | Keep calling code 1 and remove punctuation. |
| 415-555-2671 with country=US | +14155552671 | Use explicit country context before adding the calling code. |
| 0044 20 7946 0958 | +442079460958 | Convert the international access prefix 00 to +. |
| +44 (0)20 7946 0958 | +442079460958 | The domestic trunk 0 is not retained in international form. |
| 14155552671 | Needs country context | Digits without + are ambiguous unless the source contract defines the country. |
Formatting success does not prove Telegram registration, ownership, reachability, or consent.
Reject ambiguous transformations
Normalization should make known context consistent, not invent missing country or numbering information.
- Do not strip leading digits without a country-specific trunk-prefix rule.
- Do not treat +, 00, and a local leading 0 as universally interchangeable.
- Deduplicate records by the canonical value while preserving each source row.
- Route ambiguous values to correction instead of sending repeated guesses.
API input checklist
Before making a request, confirm that the identifier is canonical and traceable to the imported record.
- The value starts with + and contains digits only after it.
- The calling code came from explicit or reliable country context.
- National digits were transformed according to local numbering rules.
- Duplicates were compared using the normalized value.
- The original input remains available for review.