Build a LINE AI Bot with OpenAI (ChatGPT models)
Step-by-step guide to running a OpenAI (ChatGPT models)-powered AI bot on LINE with LangBot: model setup, bot credentials, networking, testing and troubleshooting.
This recipe puts a OpenAI (ChatGPT models) model 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.
Use OpenAI's GPT models with LangBot's built-in Agent, with optional knowledge bases, MCP tools, Skills and a code sandbox.
What you need
- A running LangBot instance: LangBot Cloud (no server needed) or a self-hosted deployment with Docker or
uvx langbot. - A OpenAI (ChatGPT models) account or server you can call from LangBot.
- 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. Add the OpenAI (ChatGPT models) model
- Create an API key in the OpenAI console.
- In LangBot, open Models, add an LLM model with the provider set to OpenAI and request URL
https://api.openai.com/v1, then paste the API key and the model ID. - Enable Tool Use if the model supports function calling; MCP tools, Skills and the sandbox need it.
- Use a current model ID from OpenAI's model list. Any OpenAI-compatible endpoint works the same way with its own request URL.
2. Create a pipeline
Open Pipelines in the LangBot WebUI, create a pipeline (or edit the default one) and set AI as follows.
| Field | Value |
|---|---|
| Runner | Local Agent (built-in Agent) |
| Model | The model you just added. You can add fallback models. |
| Prompt | Instructions: who the bot is, tone, what it must not do. |
| Knowledge Bases | Optional. Attach a knowledge base so answers come from your documents. |
3. Create the LINE bot
- Create a bot with the LINE adapter and enter the Channel Secret and Channel Access Token.
- 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
- Region or network errors: LangBot must be able to reach the request URL. Behind a restricted network, use a compatible gateway you can reach.
- 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 OpenAI (ChatGPT models) 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
- Model configuration
- Other AI back ends on LINE: Dify · n8n · Coze · Langflow · DeepSeek
- OpenAI (ChatGPT models) on other platforms: Telegram · Discord · Slack · Lark (Feishu) · DingTalk · WeCom (internal app)
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