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Getting Started with LINE over the 8x8 API

This guide takes a developer who has been handed working credentials from nothing to a first LINE message accepted by the platform. It starts with what both LINE products share, authentication and the regional base URLs, then splits: one section for the two-way LINE Official Account (LOA) channel, and one for the one-way LINE Official Notification (LON) product. They use different endpoints and address recipients differently, so read the section for the product you are integrating.

If you are still waiting on an Official Account, see Account Provisioning and Onboarding instead.

Prerequisites & Checklist​

Before you begin, ensure you have the following:

  • An 8x8 account with Messaging Apps enabled. Contact your account manager to confirm the product is enabled on your account. Sign up at connect.8x8.com if you do not have an account yet.
  • A LINE sub-account. LINE requires a new sub-account ID. It cannot be an existing SMS sub-account.
  • An API key generated in the 8x8 Connect portal, scoped to that sub-account.
  • A LINE Official Account linked to the sub-account. 8x8 configures the channel for you. See Connecting Your OA to 8x8.
  • A registered webhook. On the LOA channel you cannot obtain a recipient's channelUserId without one, so this is a hard prerequisite rather than a later step. See Configuring Your Webhook.
  • A separate sub-account per product. LOA and LON have different sending behaviour, so set up each in a different 8x8 sub-account.

Authentication​

The 8x8 Messaging Apps API accepts an ApiKey Bearer Token authentication method. Generate tokens from your customer portal at https://connect.8x8.com/, then include the following header in every request:

Authorization: Bearer {apiKey}

Replace {apiKey} with the key generated from the customer portal.

Important: The LINE Official Account sub-account token and the LINE Official Notification sub-account token are separate. A key that authorises a send on one will not authorise a send on the other.

Base URLs​

Use the base URL that matches the platform region your account is provisioned in. Sending to the wrong region will not reach your sub-account. Both LOA and LON use these same base URLs.

API RegionBase URL
Asia (default)https://chatapps.8x8.com
Europehttps://chatapps.8x8.uk
North Americahttps://chatapps.us.8x8.com
Indonesiahttps://chatapps.8x8.id

For more information on platform regions, see Platform Deployment Regions.

Sending on LINE Official Account (LOA)​

This is the two-way line channel. It carries Text, Image, Video, Audio, and Location messages, and it addresses recipients by their LINE user ID.

The Send Endpoint​

One endpoint sends every LINE Official Account message type. The type field selects the content type, and only the content object changes with it.

Endpoint:

POST https://chatapps.8x8.com/api/v1/subaccounts/{subAccountId}/messages

Path Parameters:

  • {subAccountId}: The sub-account that owns your LINE channel. 3 to 50 characters, restricted to letters, digits, and the characters -, ., _, and &.

The user, type, and content properties are required in the request body.

Getting the channelUserId First​

You cannot send a LINE message to a phone number, and you cannot look a LINE user up. The identifier you need is issued by LINE and reaches you only through an inbound event.

  1. A LINE user adds your LINE Official Account as a friend, or sends it a message.
  2. LINE notifies 8x8, and 8x8 forwards an inbound message webhook to your registered callback URL.
  3. Read the LINE user ID from payload.user.channelUserId in that webhook.
  4. Store it. That value is what you put in user.channelUserId when you send.

The format is U[0-9a-f]{32}: the letter U followed by exactly 32 lowercase hexadecimal characters. The same person has a different user ID under a different LINE provider, so an ID obtained through another integration is not usable in yours.

Key Takeaway: Until a user has interacted with your Official Account, you have no way to address them on the line channel. Design your onboarding around capturing channelUserId on first contact. See Identifying a LINE Recipient.

Send Your First Message​

The minimum viable LINE send is a text message to one user.

Sample JSON Payload:

{
  "user": {
    "channelUserId": "U3d3edab4f36c6292e6d8a8131f141b8b"
  },
  "type": "Text",
  "content": {
    "text": "Hello from 8x8 Messaging API"
  },
  "clientMessageId": "<YOUR_MESSAGE_ID>"
}

Key Fields:

  • user.channelUserId (required): The LINE user ID of the recipient. Use this instead of msisdn when sending to a LINE user on the LINE Official Account channel.
  • type (required): The content type. Written in Title Case in every 8x8 LINE example: Text, Image, Video, Audio, Location.
  • content.text (required for Text): The message body.
  • clientMessageId (optional): Your own unique reference for the message, maximum 50 characters. It is echoed back in the send response and in delivery receipts.

Note

LINE counts a text message in UTF-16 code units, with a maximum of 5,000 characters, and emoji count as more than one character. Per-type payloads and their full constraints are in LINE Official Account: Behaviour, Messages, and Constraints.

The Response​

A successful send returns 200 with the message identifier and its initial status.

Response:

{
  "umid": "<UNIQUE_MESSAGE_ID>",
  "user": {
    "channelUserId": "U3d3edab4f36c6292e6d8a8131f141b8b"
  },
  "clientMessageId": "<YOUR_MESSAGE_ID>",
  "status": {
    "state": "queued",
    "timestamp": "2026-07-29T08:19:45.99Z"
  }
}

Key Fields:

  • umid: The unique message ID (a GUID) generated by the 8x8 platform on submission. It is the platform's identifier for this message, so persist it against your own record.
  • user.channelUserId: Echoes the recipient you submitted.
  • status.state: queued on a successful submission, meaning the request was accepted and queued for processing. It is not a delivery confirmation.
  • status.timestamp: UTC, ISO 8601.
  • clientMessageId: Your own reference, echoed back.

Important: The line channel reports Accepted and Sent delivery statuses but does not report Delivered or Read. After this synchronous response, delivery receipts will arrive at your callback URL as the message progresses. See Delivery Receipts.

Error responses​

Failures at submission time come back synchronously with an error body:

HTTP statusMeaningExample body
400Bad request. A parameter is missing or invalid{"code": 1002, "message": "Invalid MSISDN format (not E.164 international number)", "errorId": "...", "timestamp": "..."}
401The request was not authenticated{"code": 1200, "message": "Request was not authenticated properly", "errorId": "...", "timestamp": "..."}
500Internal server error{"code": 2000, "message": "Internal server error", "errorId": "...", "timestamp": "..."}

Failures after acceptance arrive asynchronously as delivery receipts with a failing status.state. See Delivery Receipts.

Optional Request Options​

These properties are available on the LOA send request in addition to the required three.

  • scheduled: An ISO 8601 date-time at which delivery of the message should happen.
  • expiry: An ISO 8601 date-time after which the message should be discarded if it has not been delivered.
  • dlrCallbackUrl: A URI that overrides your account's default delivery receipt callback URL, for this message only. Use it to route delivery receipts for a specific message to a separate handler.
  • clientMessageId: Your own reference, maximum 50 characters.
  • channels: A channel fallback override array. Each entry takes:
    • channel (required): One of SMS, WhatsApp, Facebook, RCS, Viber, Line, WeChat, Zalo, Instagram. Note the capital L in Line here, which differs from the line channel type value used in inbound webhooks.
    • fallbackAfter: Seconds to wait before moving to the next channel. Minimum 10, maximum 86400 (one day).
    • successStatus: One of Accepted, Sent, Delivered, Read. This is the status that counts as success on a fallback target, so set it only to a status the target channel actually reports. The line channel reports Accepted and Sent, so set successStatus to one of those values when Line is a fallback target.

Note: The fallback chain configured by 8x8 can use the Accepted or Sent status to evaluate whether to proceed to the next channel.

Important: The fallback chain for your account is normally configured by the 8x8 team, including which channels are used, in what order, and the delay between them. Use channels only to override that configuration for a specific message.

Note

The /messages endpoint is shared across every Messaging Apps channel, so its schema carries content.interactive, content.template, content.richCard, and content.carousel. None of these are supported on the line channel. Do not treat the shared schema as the LINE surface. The supported set is listed in Supported Types at a Glance.

Sending on LINE Official Notification (LON)​

LON is a separate product, not a message type on the line channel. It is strictly one-way, every message populates a template that LINE has pre-approved, and the recipient is a phone number rather than a LINE user ID. It also has its own sub-account and its own bearer token.

Endpoint:

POST https://chatapps.8x8.com/api/v1/subaccounts/{subAccountId}/lon

Path Parameters:

  • {subAccountId}: The sub-account provisioned for LINE Official Notification. This is not the same sub-account as your LINE Official Account channel.

The user and content properties are required in the request body.

Sample JSON Payload:

{
  "user": {
    "msisdn": "+15551234567"
  },
  "clientMessageId": "<YOUR_MESSAGE_ID>",
  "content": {
    "title": "Event reminder",
    "company": "8x8",
    "icon": "calendarCheck",
    "greeting": "Can't wait to see you there!",
    "explanation": "Registration opens at 09:00. See you soon."
  }
}

Key Fields:

  • user.msisdn (required): The recipient's mobile number. International E.164 format with a leading + is preferred.
  • content.title: The message title.
  • content.company: The company name shown on the notification.
  • content.icon: The icon displayed on the notification, one of 38 documented values.
  • content.greeting: The greeting line.
  • content.explanation: The explanatory body text.

That example is trimmed. The full content schema also carries an emphasised field, a label-and-value list, action buttons, and an smsFallback object. For every property, the complete 38-value icon enumeration, the 500-character template limit, and the response shape, see LINE Official Notification (LON).

Important: You cannot compose freeform LON content at send time. Your template must be approved by LINE first, and templates are submitted through 8x8. See Template Approval.

Next Steps​

For Developers:

Important Concepts:

API Reference: