LINE Channel - PicoClaw

LINE is a popular messaging platform in Japan, Taiwan, Thailand, and Southeast Asia. PicoClaw integrates with LINE using the Messaging API via webhooks.

Why LINE?

Popular in Asia: Dominant in Japan, Taiwan, Thailand, Indonesia
Rich Features: Supports text, stickers, images, and interactive messages
Official API: Uses LINE’s official Messaging API
Group Support: Works in 1-on-1 chats and groups (responds to @mentions)

Prerequisites

LINE account
Access to LINE Developers Console
PicoClaw installed with LLM provider configured
Public HTTPS endpoint (webhook requirement)
~15 minutes for setup

Setup Instructions

Create a LINE Provider

Go to LINE Developers Console
Log in with your LINE account
Click Create a new provider
Enter a provider name (e.g., your company/project name)
Click Create

A provider is a container for your LINE channels/bots. One provider can have multiple channels.

Create a Messaging API Channel

Select your provider
Click Create a Messaging API channel
Fill in:
- Channel type: Messaging API
- Provider: Your provider (pre-selected)
- Channel name: Your bot name
- Channel description: Describe your bot
- Category: Choose appropriate category
- Subcategory: Choose subcategory
Agree to terms of service
Click Create

Get Channel Credentials

In your channel’s settings:

Go to Basic settings tab
Copy Channel Secret
Go to Messaging API tab
Scroll to Channel access token
Click Issue (if not yet issued)
Copy Channel access token

Keep these credentials secure! They grant full access to your LINE bot. Never share publicly or commit to git.

Set Up Webhook URL

LINE requires HTTPS webhooks. You need a public endpoint:Option 1: Use ngrok (testing)

# Gateway default port is 18790
ngrok http 18790

Copy the HTTPS URL (e.g., https://abc123.ngrok.io)Option 2: Reverse proxy (production)Set up nginx/Apache with SSL certificate pointing to localhost:18790Option 3: Cloud deploymentDeploy PicoClaw on a cloud server with public IP and SSL

For production, use a real domain with valid SSL certificate. Let’s Encrypt offers free certificates.

Configure Webhook in LINE

In your channel’s Messaging API tab:

Find Webhook settings
Click Edit next to Webhook URL
Enter: https://your-domain/webhook/line
Click Update
Enable Use webhook
Click Verify to test the connection

The webhook path /webhook/line is served on PicoClaw’s Gateway server (default 127.0.0.1:18790). All webhook channels share this single server.

Configure PicoClaw

Edit ~/.picoclaw/config.json:

{
  "gateway": {
    "host": "127.0.0.1",
    "port": 18790
  },
  "channels": {
    "line": {
      "enabled": true,
      "channel_secret": "YOUR_CHANNEL_SECRET",
      "channel_access_token": "YOUR_CHANNEL_ACCESS_TOKEN",
      "webhook_path": "/webhook/line",
      "allow_from": []
    }
  }
}

Replace:

channel_secret: From LINE Developers Console
channel_access_token: Channel access token (long string)
webhook_path: Default is /webhook/line (can customize)
allow_from: LINE user IDs to allow (empty = allow all)

Configure Auto-Reply Settings

In LINE Developers Console → Messaging API tab:

Disable Auto-reply messages (so only your bot replies)
Disable Greeting messages (optional)
Enable Webhooks

If auto-reply is enabled, users will get both LINE’s auto-reply AND your bot’s reply, which can be confusing.

Start the Gateway

Run PicoClaw Gateway:

picoclaw gateway

You should see:

[INFO] gateway: Starting HTTP server on 127.0.0.1:18790
[INFO] line: LINE channel initialized
[INFO] line: Webhook endpoint: /webhook/line

Test Your Bot

Scan the QR code in LINE Developers Console (Messaging API tab)
Add the bot as a friend
Send a message
The bot should respond with AI-generated replies

Configuration Options

Basic Configuration

{
  "channels": {
    "line": {
      "enabled": true,
      "channel_secret": "YOUR_CHANNEL_SECRET",
      "channel_access_token": "YOUR_CHANNEL_ACCESS_TOKEN",
      "webhook_path": "/webhook/line",
      "allow_from": []
    }
  }
}

Field	Type	Required	Description
`enabled`	boolean	Yes	Enable LINE channel
`channel_secret`	string	Yes	Channel secret from LINE Developers Console
`channel_access_token`	string	Yes	Channel access token
`webhook_path`	string	Yes	Webhook path on Gateway server (default: `/webhook/line`)
`allow_from`	array	No	List of allowed LINE user IDs (empty = allow all)

Access Control

Allow specific users:

{
  "allow_from": ["U1234567890abcdef1234567890abcdef", "Uabcdef1234567890abcdef1234567890"]
}

LINE user IDs start with U and are 33 characters long. Finding user IDs:

Check Gateway logs when a user messages the bot
Use LINE Messaging API to query user profiles
Inspect webhook payloads

Allow everyone:

{
  "allow_from": []
}

Public LINE bots can be added by anyone who scans the QR code. This may lead to unexpected API costs and potential abuse.

Webhook Requirements

HTTPS Requirement

LINE requires HTTPS for webhook URLs. HTTP is not supported. Solutions:

ngrok (testing): ngrok http 18790
Reverse proxy: nginx/Apache with SSL
Cloud deployment: Server with public IP and SSL certificate

Webhook Path

The webhook path is configured in two places:

PicoClaw config (webhook_path): /webhook/line
LINE Developers Console: https://your-domain/webhook/line

They must match.

Verification

LINE will send a verification request when you click Verify in the console. PicoClaw automatically handles this.

Features

Text Messages

Send and receive text messages with conversation context maintained per user.

Group Chats

In group chats:

Bot responds only when @mentioned (to avoid spam)
Replies quote the original message
Maintains separate context per group

To use bots in LINE groups, the bot must be added to the group by an admin.

Rich Messages

LINE supports:

Text messages
Images
Stickers
Template messages (buttons, carousels)
Quick replies
Flex messages (custom layouts)

Depending on PicoClaw implementation, advanced message types may be supported. Check the source code or documentation.

Message Types

LINE bots can receive:

Text messages
Image messages
Video messages
Audio messages
Location messages
Sticker messages

Troubleshooting

”Webhook verification failed”

Possible causes:

Gateway not running
Webhook URL incorrect
Firewall blocking incoming requests
HTTPS certificate invalid
Wrong webhook path in config

Solution:

Ensure picoclaw gateway is running
Check Gateway logs for errors
Verify webhook URL matches: https://your-domain/webhook/line
Test HTTPS endpoint with curl
Check webhook_path in config.json

Bot doesn’t respond to messages

Check these:

Webhook enabled: LINE Developers Console → Messaging API → Use webhook = ON
Auto-reply disabled: Disable auto-reply in LINE console
Allow list: User ID in allow_from or empty array
LLM configured: Test with picoclaw agent -m "test"
Gateway logs: Check for incoming webhook requests

”Invalid signature” errors

Cause: Channel secret mismatch Solution:

Verify channel_secret in config.json matches LINE Developers Console
Ensure no extra spaces when copying
Regenerate channel secret if needed
Restart gateway

”Unauthorized” errors

Cause: Invalid or expired channel access token Solution:

Go to LINE Developers Console → Messaging API
Issue new channel access token
Update channel_access_token in config.json
Restart gateway

Webhook timeouts

LINE webhook timeout: 30 seconds maximum If your LLM takes longer than 30 seconds:

Use faster LLM providers (Groq, Cerebras)
Implement async response pattern
Send “thinking” acknowledgment immediately

Gateway not accessible from internet

Check:

gateway.host set to 0.0.0.0 (not 127.0.0.1) if accessing from external network
Firewall allows port 18790
Router port forwarding configured (if behind NAT)
Cloud security groups allow inbound traffic

Rate Limits

LINE Messaging API has rate limits:

Reply messages: 50 requests/second
Push messages: Depends on plan (free tier is limited)
Multicast: 50 requests/second
Broadcast: Depends on plan

Free LINE bot accounts have limited push message quota. Reply messages (responding to user messages) are unlimited.

Privacy & Security

Security Best Practices:

Never share channel secret or access token
Use HTTPS with valid certificates
Never commit credentials to version control
Validate webhook signatures (PicoClaw does this automatically)
Use allow_from for personal bots
Monitor bot usage in LINE console
Regenerate tokens if compromised

Data Privacy

LINE bots can access:

Messages sent to the bot
User display names
User profile pictures
Group information (if in groups)

LINE user IDs are unique per bot. The same user has different IDs across different bots (privacy protection).

Be aware of:

LINE privacy policies
Local data storage in PicoClaw
LLM provider data logging
Regional data protection laws

Complete Example

{
  "agents": {
    "defaults": {
      "workspace": "~/.picoclaw/workspace",
      "model_name": "gpt4"
    }
  },
  "model_list": [
    {
      "model_name": "gpt4",
      "model": "openai/gpt-5.2",
      "api_key": "your-api-key"
    }
  ],
  "gateway": {
    "host": "0.0.0.0",
    "port": 18790
  },
  "channels": {
    "line": {
      "enabled": true,
      "channel_secret": "1234567890abcdef1234567890abcdef",
      "channel_access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
      "webhook_path": "/webhook/line",
      "allow_from": []
    }
  }
}

Production Deployment

Using Reverse Proxy

Example nginx configuration:

server {
    listen 443 ssl;
    server_name your-domain.com;

    ssl_certificate /etc/letsencrypt/live/your-domain.com/fullchain.pem;
    ssl_certificate_key /etc/letsencrypt/live/your-domain.com/privkey.pem;

    location /webhook/line {
        proxy_pass http://127.0.0.1:18790;
        proxy_set_header Host $host;
        proxy_set_header X-Real-IP $remote_addr;
        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header X-Forwarded-Proto $scheme;
    }
}

Docker Deployment

When using Docker:

# Expose Gateway port
docker compose -f docker/docker-compose.yml --profile gateway up -d

Set gateway.host to 0.0.0.0 in config to accept external connections.

Next Steps

WeCom Channel

Another Asian messaging platform

Telegram Channel

Easier setup without webhooks

Channel Overview

Compare all available channels

Configuration

Advanced configuration options

Get Started

Core Concepts

Commands

Configuration

Chat Channels

Features

Deployment

Advanced

​Why LINE?

​Prerequisites

​Setup Instructions

​Configuration Options

​Basic Configuration

​Access Control

​Webhook Requirements

​HTTPS Requirement

​Webhook Path

​Verification

​Features

​Text Messages

​Group Chats

​Rich Messages

​Message Types

​Troubleshooting

​”Webhook verification failed”

​Bot doesn’t respond to messages

​”Invalid signature” errors

​”Unauthorized” errors

​Webhook timeouts

​Gateway not accessible from internet

​Rate Limits

​Privacy & Security

​Data Privacy

​Complete Example

​Production Deployment

​Using Reverse Proxy

​Docker Deployment

​Next Steps

WeCom Channel

Telegram Channel

Channel Overview

Configuration

Build docs developers (and LLMs) love

Why LINE?

Prerequisites

Setup Instructions

Configuration Options

Basic Configuration

Access Control

Webhook Requirements

HTTPS Requirement

Webhook Path

Verification

Features

Text Messages

Group Chats

Rich Messages

Message Types

Troubleshooting

”Webhook verification failed”

Bot doesn’t respond to messages

”Invalid signature” errors

”Unauthorized” errors

Webhook timeouts

Gateway not accessible from internet

Rate Limits

Privacy & Security

Data Privacy

Complete Example

Production Deployment

Using Reverse Proxy

Docker Deployment

Next Steps