Connect Langflow to LINE

This recipe puts your Langflow app behind a LINE bot. LangBot receives messages from LINE, runs them through a pipeline, and sends the answer back, so you do not write any platform code.

Langflow builds agents and flows with a drag-and-drop editor. LangBot runs a flow through the Langflow API for every message.

What you need

• A running LangBot instance: LangBot Cloud (no server needed) or a self-hosted deployment with Docker or uvx langbot.
• A Langflow account or instance that LangBot can reach over the network.
• A Messaging API channel in the LINE Developers Console: Channel Secret and Channel Access Token (click Issue).

Networking

LINE calls a webhook, so LangBot needs a public HTTPS URL. LangBot Cloud includes a domain and HTTPS.

1. Prepare Langflow

1. Build a flow in Langflow (the Simple Agent template is a good start).
2. Create an API key under Settings.
3. Copy the Flow ID from Share → API access.

2. Create a pipeline

Open Pipelines in the LangBot WebUI, create a pipeline (or edit the default one) and set AI as follows. If the runner is not listed, install the official runner plugin from Plugins or the LangBot Space marketplace.

3. Create the LINE bot

1. Create a bot with the LINE adapter and enter the Channel Secret and Channel Access Token.
2. Copy the webhook callback URL from LangBot into the channel's Webhook URL, verify it, and turn on Use webhook.

4. Bind and test

Open the bot, select the pipeline you created, save and make sure the bot is enabled.

Add the official account as a friend with its QR code and send a message.

Troubleshooting

• Connection refused: http://localhost:7860 only works when Langflow runs on the same host and network namespace as LangBot.
• Webhook verification fails: check the URL and that HTTPS works from the public internet.
• No replies: turn off LINE's auto-reply messages in the Official Account Manager so they do not answer instead of the bot.
• Check Monitoring in the WebUI: every message, pipeline run and error is recorded there.

FAQ

Do I need a server with a public IP for LINE?

Yes, or use LangBot Cloud. LINE calls a webhook, so LangBot needs a public HTTPS URL. LangBot Cloud includes a domain and HTTPS.

Does the LINE bot support streaming replies?

Check the platform feature matrix for what this platform supports. Replies are delivered once the AI back end has finished.

Can the same Langflow setup serve other platforms too?

Yes. A pipeline can be bound to many bots, so one configuration can answer on several platforms at once.

Related guides

• Full LINE setup guide
• Full Langflow runner guide
• Other AI back ends on LINE: Dify · n8n · Coze · DeepSeek · OpenAI (ChatGPT models)
• Langflow on other platforms: Telegram · Discord · Slack · Lark (Feishu) · DingTalk · WeCom (internal app)