Get Telegram API credentials:
- Visit https://my.telegram.org
- Login with your phone number
- Go to "API development tools"
- Create new application to get API ID and API Hash

Clone the repository:

git clone <repository-url>
cd <repository-name>

Create environment file:
```
cp .env.example .env
```

Configure environment variables in .env:

PHONE=+1234567890
API_ID=12345678
API_HASH=your_api_hash_here
GROUP_ID=-1001234567890
OUTPUT_DIR=out
VERBOSE=false

# Export options (default: true for ID, username, first_name, last_name; false for others for privacy)
INCLUDE_ID=true
INCLUDE_USERNAME=true
INCLUDE_FIRST_NAME=true
INCLUDE_LAST_NAME=true
INCLUDE_IS_BOT=false
INCLUDE_IS_SCAM=false
INCLUDE_IS_FAKE=false
INCLUDE_PHONE_NUMBER=false

# Optional proxy settings
PROXY_HOST=proxy.example.com
PROXY_PORT=443
PROXY_SECRET=your_proxy_secret

Usage

Basic Usage

Run the application:
```
go run main.go
```
If GROUP_ID is not specified in the environment, the application will show a list of accessible groups for you to select from.
Enter the authentication code sent to your Telegram when prompted.
The application will export the member list to a JSON file in the out/ directory.

Configuration Options

GROUP_ID: Specify a group ID directly to export from that group
OUTPUT_DIR: Directory to save the exported JSON file (default: out)
VERBOSE: Enable verbose logging (default: false)
INCLUDE_*: Control which member fields to include in the export

Export Format

The exported JSON file contains:

{
  "members": [
    {
      "id": 123456789,
      "username": "username",
      "first_name": "First",
      "last_name": "Last",
      "is_bot": false,
      "is_scam": false,
      "is_fake": false,
      "phone_number": "1234567890"
    }
  ],
  "memberCount": 150,
  "exportTime": "2025-12-06T17:11:00Z"
}

Building

To build the application:

go build -o telegram-exporter main.go

Then run:

./telegram-exporter

Error Handling

The application includes robust error handling for:

Authentication failures
Invalid group IDs or inaccessible groups
Rate limiting by Telegram API
Network timeouts
Transient network failures (with retry logic)

Performance

Supports exporting large groups with thousands of members
Implements pagination to handle large datasets
Includes performance timing to monitor export duration

Security Considerations

Store your Telegram API credentials securely
Don't commit .env file to version control
Be mindful of privacy settings when exporting member information
Only export member information you have permission to access

Troubleshooting

Authentication Issues

Ensure phone number is in international format (+1234567890)
Verify API credentials are correct
Check that phone number is properly registered with Telegram

Group Access Issues

Verify the group ID is correct
Ensure you have access to the group
Confirm you're using the correct format (negative ID for supergroups)

Network Issues

Check internet connection
If behind firewall, try using proxy settings
Verify API endpoints are not blocked in your region

License

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