> ## Knowledge Base Index
> Fetch the complete knowledge base index at: https://help.1lookup.io/sitemap.xml
> Use this file to discover available pages before exploring further.
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# Number type check: mobile, landline, VoIP or toll-free

A number type lookup classifies a phone number and tells you whether it is valid. Use it to route contacts to the right channel, for example sending SMS only to numbers that can receive it.

## What it tells you

- What kind of number it is: mobile, landline, VoIP or toll-free.
- Whether the number is valid.
- The carrier the number belongs to.
- The country the number belongs to.
- A suggested next action based on the result.

## What you need to provide

The phone number you want to classify. International format (E.164) is strongly recommended.

## What it costs

1 credit per lookup. Live per-product costs are shown on the Billing page in your dashboard.

## How to run it

- In the dashboard: Number Type Detection
- From your code: POST /v1/nt-lookup, then see the Developer Hub at app.1lookup.io/developer-hub.

## Good to know

- This tells you what a number is, not whether a handset is switched on at this moment.
- Results are point-in-time. Numbers get reassigned, and a line can move between number types, so re-check numbers you have held for a while.
- Number Validation covers line type alongside carrier, location and a fraud score in one call. Use this lookup when the number type is all you need.
- VoIP is not the same as bad. Plenty of real people and businesses use VoIP lines, so decide for yourself how to treat them rather than rejecting them outright.