Technical note
A correctly formatted phone number that still cannot be used
Updated 26 September 2026
+1 212 555 0142 is a real United States number in the sense that matters to most code. Eleven digits, a valid area code, and it matches the published numbering plan for the United States. It will pass a form, save to a database and sit in a CRM looking exactly like every other number in the column.
It is also in a block NANPA reserves for fiction. No operator assigns it to anybody, so the first time it matters, it fails.
What the ranges are
Regulators publish blocks that exist so a number can be used in a film, a training manual or a test suite without reaching a real person.
| Region | Range | Authority | What it means |
|---|---|---|---|
| United States and Canada | 555-0100 to 555-0199 | NANPA | Reserved for fictional use across every area code. The wider 555 prefix is not all fictional: other 555 numbers can be assigned, and some are used for information services. |
| United Kingdom | Ofcom drama ranges | Ofcom | Ofcom reserves blocks for drama and fiction, including numbers in 020 7946 0000 to 0999 for London. They are published so that a number read out on television does not ring a real household. |
Is every 555 number fake?
No. The reserved block is narrow: 555-0100 to 555-0199, within any area code. Numbers outside that block but still beginning 555 are ordinary numbers as far as the numbering plan is concerned, and some of them are assigned and in use for information services.
That distinction is the reason a check has to look at the range rather than the prefix. Treating all of 555 as fictional would reject numbers that work, which is the same class of mistake in the other direction.
Why one ends up in your database
These numbers are the ones people reach for when they do not want to give you a real one, and the ones that get typed into a form during testing and never cleaned up. They are designed to look correct, so every check that asks whether the digits are well formed says yes.
The cost lands later and somewhere else. A lead is captured, routed, assigned and worked, and the failure surfaces at the moment somebody in sales or support actually tries to call. By then the record has been counted, reported on, and possibly paid for.
What a check returns for one
This is the live response for that number, not an illustration.
This phone number will not work
- verdict
- rejected
- risk_score
- 64
- evidence_coverage
- 72
- credits
- 1
recommendation
Do not accept this phone number. Ask for a replacement at the point of capture.
| Capability | State | What it says |
|---|---|---|
| Format | VERIFIED | Parsed successfully |
| Plan validity | FAILED | Matches the national numbering-plan pattern, but the range is not assignable: NANPA reserves 555-0100 to 555-0199 for fictional use. |
| Carrier | NOT OFFERED | Orisift does not currently contract a carrier-data provider, so the operator of this line is not looked up. |
| Reachability | NOT OFFERED | Nothing here dials or pings the number. Plan validity is not evidence that a line is active or reachable. |
The registry line, with its source
NANPA reserves 555-0100 to 555-0199 for fictional use. No operator assigns these to subscribers.
source: National regulator allocations
Note the first two rows of that table together. The format is verified and the plan validity fails, in the same response, for the same number. That is the whole of the problem in two lines: correctly formed and not assignable are separate questions, and only one of them can be answered by looking at the digits.
What this does not tell you
That the number is reachable
Nothing in the check dials or pings anything. A number outside a reserved range can still be disconnected, unassigned or simply not answered.
That other numbers work
A range being assignable means an operator may assign it, not that this one is assigned to anybody.
Who holds it
No carrier lookup, no porting data and no subscriber information of any kind.
Run the number above yourself. Three checks a day, no account.