---
title: "Check portability"
method: POST
path: "/v1/phone-numbers/port-in/check"
tags: ["Phone Numbers"]
---

# Check portability

`POST /v1/phone-numbers/port-in/check`

Pre-flight portability check: whether each number can be ported in and
whether it qualifies for FastPort, BEFORE the user commits to a port
order (LOA, invoice, service address). Read-only; creates no order and
bills nothing.

## Request body

- object
  - `phoneNumbers` string[], required — E.164 numbers to check, e.g. +13035550000.

## Response `200`

Per-number portability.

- object
  - `results` object[]
    - `phoneNumber` string
    - `portable` boolean
    - `fastPortable` boolean — Qualifies for the carrier's accelerated FastPort lane.
    - `lineType` string, nullable — Line type when known (mobile, landline, voip…). A US/CA mobile number requires the transfer PIN at submit.
    - `countryCode` string, nullable — ISO country of the number — pass it to GET /v1/phone-numbers/port-in/requirements for international numbers.
    - `phoneNumberType` string, nullable — Carrier number-type classification (local, mobile, national, toll_free…) — the numberType for the requirements endpoint.
    - `notPortableReason` string, nullable — Carrier reason when not portable; null when portable.

## Other responses

- `401` — Unauthorized

---

[API](https://skmtc.net/zernio/apis/zernio-api.md) · [All operations](https://skmtc.net/zernio/apis/zernio-api/llms.txt) · [OpenAPI document](https://skmtc-service-staging.skmtc.workers.dev/v1/apis/zernio/zernio-api/revisions/19fd2b70854e/schema)