---
title: "Carrier Lookup (original carrier) API"
url: "https://lookvalid.com/products/carrier-lookup.md"
canonical_url: "https://lookvalid.com/products/carrier-lookup"
last_updated: "2026-10-22"
type: "product"
summary: "The carrier originally assigned a US number block: company name, operating company number (OCN), rate center and state."
related: ["https://lookvalid.com/pricing.md", "https://lookvalid.com/docs/api/carrier-lookup.md"]
---

# Carrier Lookup (original carrier) API

The carrier originally assigned a US number block: company name, operating company number (OCN), rate center and state.

The carrier originally assigned a US number block: company name, operating company number (OCN), rate center and state, from the public NANPA central office code and thousands-block reports, with the report date. Porting is not reflected (ported: unknown), so a number moved to another carrier still shows its original one. NANPA data has no carrier category, so line type is only a hint from the carrier name. Canada and the Caribbean are not covered.

## Facts

- Endpoint: `POST https://YOUR_API_HOST/v1/carrier-lookup`
- Price: 1 credit per lookup (numbers outside the covered numbering plan areas are free)
- Charged: Only when a lookup finds something
- Cache: repeating the same lookup within 7 days is free

## Example request

```sh
curl -X POST https://YOUR_API_HOST/v1/carrier-lookup \
  -H "Authorization: Bearer $LOOKVALID_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"phone":"+14155550132"}'
```

## Response

The `data` object has 15 named fields. Every response also lists the sources behind the result, the credits charged and whether it was served from your cache.

| Field | Type | Description |
| --- | --- | --- |
| `phone_e164` | string |  |
| `npa_nxx_block` | object |  |
| `original_carrier` | object |  |
| `rate_center` | string or null |  |
| `state` | string |  |
| `assignment_level` | "thousands_block" | "central_office_code" |  |
| `code_holder` | object | Holder of the whole central office code; differs from the carrier when the code is pooled |
| `in_service` | boolean |  |
| `assigned_since` | string or null |  |
| `line_type` | "mobile" | "unknown" |  |
| `line_type_basis` | "carrier name keywords, not an official category" |  |
| `ported` | "unknown" |  |
| `data_date` | string | Date of the NANPA central office code report |
| `blocks_data_date` | string | Date of the NANPA thousands-block file |
| `notes` | string |  |

## Priced in credits

| Case | Charge |
| --- | --- |
| Found | 1 credit |
| Nothing found | 0 credits |
| Repeat inside 7 days | 0 credits |
| Errors and invalid requests | 0 credits |

## Questions

### How much does Carrier Lookup (original carrier) cost?

1 credit per lookup (numbers outside the covered numbering plan areas are free). Credits come out of the one balance shared by every LookValid product.

### Am I charged when nothing is found?

No. When the lookup runs and finds nothing, it returns found: false and costs 0 credits. An error costs nothing either.

### How long are results cached?

For 7 days, per account. Repeating the same lookup inside that window returns cache_hit: true and costs 0 credits.

### Which API key do I use?

The same key as every other product. Send it as a Bearer token in the Authorization header. Email hello@lookvalid.com and we set up your account and send the key.

## Related products

- [Phone Numbering-Plan Validation](https://lookvalid.com/products/phone.md): Checks a phone number against its country's numbering plan and returns E.164, national and international formats, the country and the number type the plan assigns (mobile, fixed line, toll free, VoIP and others).
- [Country Calling Codes](https://lookvalid.com/products/country-code.md): Looks up a country by calling code (+44), ISO region (GB) or English country name and returns the calling code, every region that shares it, national number lengths, trunk and international dialing prefixes, example numbers and the leading digits of mobile and fixed-line numbers where the numbering plan defines them.
- [Email Domain Check](https://lookvalid.com/products/email-domain-check.md): Checks the domain behind an email address: MX records, SPF and DMARC policies, and whether the address uses a disposable domain, a free mailbox provider or a role mailbox such as info@ or support@.

Full request and response fields: [Carrier Lookup (original carrier) reference](https://lookvalid.com/docs/api/carrier-lookup.md).

## Related

- [Plans, trial and credit pricing](https://lookvalid.com/pricing.md)
- [Carrier Lookup (original carrier) reference](https://lookvalid.com/docs/api/carrier-lookup.md)