---
ref: tool:twilio/look-up-phone-number
name: Look up a phone number
company: company:twilio
workflows: []
access: [cli]
tags: [capability:enrich-contacts, category:messaging, has:cli]
docs: https://www.twilio.com/docs/lookup/v2-api#making-a-request
updated: 2026-09-27
---

# Look up a phone number

Validates a phone number and returns it in E.164 and national formats, plus line type, caller name or other data you request.

Pass `--phone-number` in E.164 format. The basic lookup (formatting and
validation) is free; add paid data packages with `--fields`, such as
`line_type_intelligence` (mobile, landline, VoIP and more) or `caller_name`
(US numbers only). Some packages need Twilio's approval first. The REST call
is `GET https://lookups.twilio.com/v2/PhoneNumbers/{PhoneNumber}`. The CLI
also needs `TWILIO_ACCOUNT_SID` and `TWILIO_API_SECRET`, or a `twilio login`
profile.

## Set up

Use the first option your agent supports.

### CLI (official)

Install the command, then confirm it runs.

```sh
brew tap twilio/brew && brew install twilio
twilio --version
```

Run `twilio api:lookups:v2:phone-numbers:fetch`.

Set `$TWILIO_API_KEY` in your environment first (get a key: https://www.twilio.com/docs/iam/api-keys/keys-in-console).

Before doing anything else, make one read-only call to confirm access.

## Rules

- Ask the user before anything that sends messages, costs money, or changes data.
- Never print API keys.