# Get access to the SMS API

> An Owner or Admin requests SMS API access in Integrations. After Line approves it, create test keys to try the sandbox and live keys to send real texts.

Source: https://useline.io/help/integrations/sms-api  
Section: Integrations and API  
Last updated: 2026-11-05  
Roles: Owner, Admin

The SMS API lets your own software send and receive texts from your Line numbers. Line must approve your workspace first. Then you create API keys in **Integrations** > **SMS API**.

The full API reference, quickstart and code samples are at [/developers](https://useline.io/developers).

## Before you start

- You need the **Owner** or **Admin** role.
- You need a Line number that can send SMS.
- You must have consent to text every recipient, and you must honour opt-outs.

## Request access

1. In the main menu, select **Integrations**.
2. Select **SMS API**.
3. Select **Set up SMS API**. The **API access** page opens.
4. In **Use case**, describe what you will send.
5. In **Expected messages each month**, enter a number.
6. In **Consent process**, describe how recipients agree to get texts.
7. Select the consent check box.
8. Select **Request access**.

The **Status** changes to **Pending**. Line reviews the request. When Line approves it, the status changes to **Active**. If Line rejects it, the page shows the reason.

## Create an API key

1. Open **Integrations** > **SMS API** > **API access**.
2. In **API keys**, select **Create key**.
3. Enter a **Name**.
4. In **Environment**, select **Test** or **Live**.
5. In **Sender**, select the number that the key can send from.
6. Select the **Scopes** that the key needs.
7. Select **Create key**.
8. Select **Copy** and store the key in a safe place.

> **Important:** Line shows the full key only once. If you lose it, create a new key and revoke the old one.

Test keys start with `line_sk_test_`. Live keys start with `line_sk_live_`.

## Test with the sandbox

A test key uses the same URLs as a live key. It sends no real texts and uses no credits. Its messages, events and webhooks stay apart from your live data.

The last four digits of the recipient number set the result:

| Recipient ends in | Result |
|---|---|
| `0002` | `failed` |
| `0003` | `undelivered` |
| Any other digits | `delivered` |

You can also simulate a customer reply, STOP or START with a test key. See the sandbox section at [/developers](https://useline.io/developers).

## Request a sender name

A sender name shows instead of a number, for example ACMEDENTAL. Recipients cannot reply to it. It sends only to UK and Irish numbers.

1. Open **Integrations** > **SMS API** > **API access**.
2. In **Sender names**, select **Request name**.
3. Enter a name of 3 to 11 letters, numbers or spaces.
4. Select **Request name**.

Line reviews each name. Use only your own business name or brand.

## Costs

Live sends use credits from your credit wallet, per segment. Line reserves the credits when it accepts the message. A UK send that the network reports as `failed` or `undelivered` gets its credits back. See [Credits and usage](https://useline.io/help/billing/credits-and-usage).

## Common problems

**I do not see SMS API in Integrations.** Only Owners and Admins see it.

**My request is still Pending.** Line reviews each request by hand. Contact support@useline.io if you need a decision.

**A live send is refused for credits.** Sends stop when the wallet has fewer than 20 credits. Buy credits or turn on automatic top-up.

## Related articles

- [What you can connect to Line](https://useline.io/help/integrations/integrations-overview.md): Line connects to Google Calendar, Microsoft Calendar, your own HTTP and MCP tools, and the SMS API. Email to SMS works with any software that sends email.
- [Send texts by email with an Email to SMS gateway](https://useline.io/help/integrations/email-to-sms.md): Create a gateway in Channels > Email to SMS. Email the gateway address with a mobile number in it, and Line texts the email body from your Line number.
- [How credits and the credit wallet work](https://useline.io/help/billing/credits-and-usage.md): Line is prepaid. Calls, texts, WhatsApp, extra email and AI replies use credits from your wallet. One credit is 1p. Automatic top-up refills it.
- [Send and reply to text messages](https://useline.io/help/messaging/send-sms.md): Send an SMS from the Inbox with New message, or reply in the conversation. Texts leave from your Line number and cost credits per segment.