---
title: LINE
description: Community LINE Messaging API adapter for Chat SDK with Flex Message cards, inbound media, action postbacks, and typing indicators.
tagline: LINE Messaging API adapter for Chat SDK. Send text and Flex Message cards, receive media and postback actions, and verify signed webhooks.
package: chat-adapter-line
---

# LINE



## Install

<PackageInstall package="chat-adapter-line chat @chat-adapter/state-memory" />

## Quick start

```typescript title="lib/bot.ts" lineNumbers
import { Chat } from "chat";
import { createLineAdapter } from "chat-adapter-line";
import { createMemoryState } from "@chat-adapter/state-memory";

const bot = new Chat({
  userName: "mybot",
  adapters: {
    line: createLineAdapter(),
  },
  state: createMemoryState(),
});

bot.onDirectMessage(async (thread, message) => {
  await thread.post(`You said: ${message.text}`);
});
```

The memory state adapter keeps subscriptions and locks in process memory, which suits local development. Use [Redis](/adapters/official/redis) or [PostgreSQL](/adapters/official/postgres) in production.

When called with no arguments, `createLineAdapter()` reads `LINE_CHANNEL_ACCESS_TOKEN` and `LINE_CHANNEL_SECRET` from the environment.

## Platform setup

1. Create a provider and channel in the [LINE Developers Console](https://developers.line.biz/console/).
2. Enable the Messaging API for the channel.
3. Copy the channel access token and channel secret.
4. Set the webhook URL to a public HTTPS endpoint, such as `https://your-domain.com/api/webhooks/line`.
5. Subscribe to message and postback events.

## Configuration

<TypeTable
  type={{
  channelAccessToken: {
    type: "string",
    description:
      "LINE channel access token. Falls back to `LINE_CHANNEL_ACCESS_TOKEN`.",
  },
  channelSecret: {
    type: "string",
    description:
      "LINE channel secret. Falls back to `LINE_CHANNEL_SECRET`.",
  },
  userName: {
    type: "string",
    default: '"line-bot"',
    description: "Bot display name used by Chat SDK.",
  },
  logger: {
    type: "Logger",
    description: "Custom Chat SDK logger. Defaults to `ConsoleLogger`.",
  },
}}
/>

### Environment variables

| Variable                    | Required | Description                                                      |
| --------------------------- | -------- | ---------------------------------------------------------------- |
| `LINE_CHANNEL_ACCESS_TOKEN` | Yes      | LINE channel access token, unless you pass `channelAccessToken`. |
| `LINE_CHANNEL_SECRET`       | Yes      | LINE channel secret, unless you pass `channelSecret`.            |

## Webhooks

```typescript title="app/api/webhooks/line/route.ts" lineNumbers
import { after } from "next/server";
import { bot } from "@/lib/bot";

export async function POST(request: Request): Promise<Response> {
  return bot.webhooks.line(request, {
    waitUntil: (task) => after(() => task),
  });
}
```

LINE sends each webhook with an `x-line-signature` header. The adapter computes an HMAC-SHA256 digest with the channel secret and compares it with the header before parsing the body.

## Messages and cards

Text and Markdown output are converted to plain text. Chat SDK cards become LINE Flex Messages: the card title and text become the bubble body, and buttons become postback actions in the footer. Button clicks dispatch to Chat SDK action handlers.

## Attachments

The adapter receives image, video, audio, and file messages as attachments. It doesn't upload outbound files. Posting a message with files logs a warning and sends any text or card content.

## Streaming

Streaming is buffered. The adapter sends a text message after it collects more than 500 characters, then sends the remaining text after the stream ends. It sends at most five messages per stream.

## Thread IDs

```text
line:<channelId>:<sourceType>:<sourceId>
```

`sourceType` is `user`, `group`, or `room`. `sourceId` is the LINE user, group, or room ID.

## Feature support

<FeatureSupport />