A lightweight, local emulator for the LINE Messaging API that allows developers to test their LINE bot applications without connecting to the actual LINE servers. This emulator implements the endpoints defined in the official LINE OpenAPI specifications, including messaging endpoints and webhook handling.

• Local Testing Environment: Test your LINE bot locally without requiring internet access or LINE accounts
• Messaging API Coverage: Implements endpoints from the official LINE Messaging API specification
• Webhook Support: Simulates webhook events for testing bot responses
• No Authentication Required: Skip the complexity of managing channel access tokens during development
• OpenAPI Compliant: Based on the official LINE OpenAPI specifications for accuracy

• Go 1.24.4 or higher
• Make (optional, for using Makefile commands)
• Atlas CLI (curl -sSf https://atlasgo.sh | sh -s --)

Clone the repository:

git clone https://github.com/zero-color/line-messaging-api-emulator.git
cd line-messaging-api-emulator

Install dependencies:

go mod download

Start the emulator server using one of the following methods:

Using Make:

make run

Using Go directly:

go run ./cmd/server

With custom port:

go run ./cmd/server --port 8080

By default, the server runs on port 9090.

The project includes a Makefile with helpful commands:

• make run - Start the emulator server
• make test - Run all tests
• make lint - Run code linters
• make help - Display all available commands

The emulator implements the following LINE Messaging API endpoints:

• GET /v2/bot/channel/webhook/endpoint - Get webhook endpoint information
• PUT /v2/bot/channel/webhook/endpoint - Set webhook endpoint URL
• POST /v2/bot/channel/webhook/test - Test webhook endpoint

• POST /v2/bot/message/reply - Send reply message
• POST /v2/bot/message/push - Send push message
• POST /v2/bot/message/multicast - Send multicast message
• POST /v2/bot/message/narrowcast - Send narrowcast message
• POST /v2/bot/message/broadcast - Send broadcast message

• GET /v2/bot/message/{messageId}/content - Download image, video, and audio data
• GET /v2/bot/message/{messageId}/content/preview - Get preview image
• GET /v2/bot/message/{messageId}/content/transcoding - Check transcoding status

• GET /v2/bot/profile/{userId} - Get user profile
• GET /v2/bot/followers/ids - Get follower IDs

• GET /v2/bot/group/{groupId}/member/{userId} - Get group member profile
• GET /v2/bot/room/{roomId}/member/{userId} - Get room member profile
• POST /v2/bot/group/{groupId}/leave - Leave group
• POST /v2/bot/room/{roomId}/leave - Leave room

• POST /v2/bot/richmenu - Create rich menu
• GET /v2/bot/richmenu/{richMenuId} - Get rich menu
• DELETE /v2/bot/richmenu/{richMenuId} - Delete rich menu
• GET /v2/bot/richmenu/list - Get rich menu list

For a complete list of endpoints, refer to the OpenAPI specification.

.
├── cmd/
│   └── server/         # Server entrypoint
│       └── main.go
├── line-openapi/       # LINE OpenAPI specifications
│   ├── messaging-api.yml
│   ├── webhook.yml
│   └── ...
├── go.mod              # Go module dependencies
├── go.sum              # Go module checksums
├── Makefile            # Build and development commands
└── README.md           # This file

Run the test suite:

make test

The tests use gotestsum for better output formatting and include race condition detection.

Run linters to ensure code quality:

make lint

The project uses golangci-lint for comprehensive code analysis.

The server accepts the following command-line options:

• --port - HTTP port number (default: 9090)
• --help - Display help information

Example:

go run ./cmd/server --port 8080

To use this emulator with your LINE bot application:

1. Start the emulator server
2. Configure your bot application to use http://localhost:9090 as the LINE API base URL
3. Point webhook URLs to your bot application
4. Send test messages through the emulator's API endpoints

Example webhook test:

curl -X POST http://localhost:9090/v2/bot/channel/webhook/test \
  -H "Content-Type: application/json" \
  -d '{
    "endpoint": "http://localhost:3000/webhook"
  }'

Contributions are welcome! Please feel free to submit issues and pull requests.

This project is licensed under the terms specified in the LICENSE file.

• Based on the official LINE OpenAPI specifications
• Built with chi router for HTTP routing

This is an unofficial emulator for development and testing purposes only. It is not affiliated with or endorsed by LINE Corporation. For production use, always use the official LINE Messaging API.

For issues, questions, or suggestions, please open an issue on the GitHub repository.