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How to Get a User's Username by ID in Telegram

Learn effective methods to get a user's username by ID in Telegram for JavaScript bots. Performance optimization in groups and handling hidden users.

#bot-optimization#data-caching#getchat-method#hidden-users#javascript-telegram#telegram-bot-api#username-by-id
Question

How to get a user’s username by their ID in Telegram?

I created a JavaScript bot for Telegram that authenticates through https://my.telegram.org/auth and connects to a chat. When the bot receives a message, it needs to process it and reply to the sender.

The problem is that the current logic for searching users across the entire group is inefficient because:

  1. There can be many users in the group
  2. An admin might hide all users except for the admin/moderator team

Please advise on how to properly implement getting a user’s username by their ID under these conditions?

P.S. The bot is intended for automatically answering questions, not for spam or advertising.

NeuroAgent

Short Answer

There is no direct method in the Telegram Bot API to get a user’s username by their ID. However, you can use the getChat method with a chat_id parameter containing the user ID in the format user_id, or the users.getFullUser method from unofficial libraries. For efficient searching in groups, it’s recommended to cache user information and use built-in message objects.

Table of Contents

Main Methods for Getting User Information

In the Telegram Bot API, there are several ways to get information about a user, but no direct method exists for getting a username by ID. The main approaches include:

  1. getChat method - allows you to get information about a chat or user
  2. users.getFullUser method - unofficial method for extended user information
  3. Using message objects - when receiving messages from users

Important: Telegram API does not provide a direct method for getting a username by user ID. This limitation is related to privacy policies.

Using the getChat Method

The primary way to get user information by their ID is to use the getChat method. In Telegram, a user ID can be used as chat_id:

javascript
// Format of user ID for getChat: 'user' + user_id
const userId = 123456789;
const chatId = `user_${userId}`;

bot.getChat(chatId).then(chat => {
    console.log('Username:', chat.username);
    console.log('First name:', chat.first_name);
    console.log('Last name:', chat.last_name);
}).catch(error => {
    console.error('Error getting user information:', error);
});

According to the official Telegram Bot API documentation, the getChat method allows you to get information about a chat, including users. However, there are limitations:

  • In groups, administrators can hide user information
  • The bot must be an administrator in the group to access information about other users
  • Some users may have hidden their username

Alternative Approaches with node-telegram-bot-api

The node-telegram-bot-api library provides convenient methods for working with users:

javascript
const TelegramBot = require('node-telegram-bot-api');

const bot = new TelegramBot(TOKEN, { polling: true });

// Getting bot information
bot.getMe().then(function (info) {
    console.log(`${info.first_name} is ready, username: @${info.username}`);
});

// Handling messages and accessing sender information
bot.on('message', (msg) => {
    const userId = msg.from.id;
    const username = msg.from.username;
    const firstName = msg.from.first_name;
    
    console.log(`User ${firstName} (ID: ${userId}, Username: @${username})`);
});

As shown in the examples from TabNine, when receiving messages, all user information is already available in the msg.from object.

Performance Optimization in Groups

For efficient work in groups with a large number of users, the following is recommended:

1. Caching User Information

javascript
const userCache = new Map();

// Function for getting user information with caching
async function getUserInfo(userId) {
    // Check cache
    if (userCache.has(userId)) {
        return userCache.get(userId);
    }
    
    try {
        const chatId = `user_${userId}`;
        const chat = await bot.getChat(chatId);
        
        const userInfo = {
            id: userId,
            username: chat.username || null,
            firstName: chat.first_name,
            lastName: chat.last_name || null
        };
        
        // Cache the information
        userCache.set(userId, userInfo);
        return userInfo;
    } catch (error) {
        console.error(`Error getting user information for ${userId}:`, error);
        return null;
    }
}

2. Using Built-in Message Data

Instead of making constant API requests, use the already available information:

javascript
bot.on('message', async (msg) => {
    const userId = msg.from.id;
    
    // If username is already in the message, use it
    if (msg.from.username) {
        console.log(`Username: @${msg.from.username}`);
        return;
    }
    
    // Otherwise, request the information
    const userInfo = await getUserInfo(userId);
    if (userInfo) {
        console.log(`Username: @${userInfo.username || 'not specified'}`);
    }
});

Practical Code Examples

Example 1: Responding to Messages with User References

javascript
bot.onText(/\/reply (.+)/, async (msg, match) => {
    const userId = parseInt(match[1]);
    const userInfo = await getUserInfo(userId);
    
    if (userInfo) {
        const response = userInfo.username 
            ? `@${userInfo.username}`
            : `${userInfo.firstName} ${userInfo.lastName}`;
        
        bot.sendMessage(msg.chat.id, `Replying to user: ${response}`);
    } else {
        bot.sendMessage(msg.chat.id, 'Could not find user');
    }
});

Example 2: Checking Access Permissions

javascript
// Storing admin IDs
const adminIds = [123456789, 987654321];

async function isAdmin(userId) {
    if (adminIds.includes(userId)) return true;
    
    try {
        const chat = await bot.getChatAdmins(msg.chat.id);
        return chat.some(admin => admin.user.id === userId);
    } catch (error) {
        console.error('Error checking permissions:', error);
        return false;
    }
}

Handling Hidden Users

In groups where administrators have hidden user information, the following limitations exist:

  1. Users without usernames - impossible to get @username, only first and last name
  2. Limited access - bot can only see users it has interacted with
  3. Administrator rights - bot must be an administrator to get information about other users

Recommendations for working with hidden users:

javascript
async function getSafeUserInfo(userId) {
    try {
        const userInfo = await getUserInfo(userId);
        
        if (!userInfo) {
            return { 
                id: userId, 
                displayName: `User ${userId}`,
                username: null 
            };
        }
        
        return {
            id: userInfo.id,
            displayName: userInfo.username 
                ? `@${userInfo.username}`
                : `${userInfo.firstName} ${userInfo.lastName}`,
            username: userInfo.username
        };
    } catch (error) {
        console.error('Error getting information:', error);
        return {
            id: userId,
            displayName: `User ${userId}`,
            username: null
        };
    }
}

Conclusion

  1. No direct method exists in Telegram API to get username by ID. Use the getChat method with the format user_${userId}.

  2. Optimize performance in groups by caching user information and using built-in message data.

  3. Consider limitations - administrators can hide user information, and some users may not have usernames.

  4. Implement error handling - when user information is unavailable, use alternative identification methods.

  5. For production bots - always request necessary access rights and follow Telegram’s privacy policies.

Additional resources for study: official Telegram Bot API documentation and the node-telegram-bot-api repository.

Sources

  1. Telegram Bot API - getChat method
  2. Stack Overflow - Telegram Bot: Is it possible to get userid using username?
  3. TabNine - node-telegram-bot-api.User.username examples
  4. GitHub - node-telegram-bot-api issues
  5. Telegram Bot API documentation
How to check a user's admin rights in a Telegram bot?How to handle messages from users without usernames in Telegram?How to optimize bot performance in large Telegram groups?What limitations exist when getting user information in Telegram?How to implement a user caching system for a Telegram bot?How to get full user information in Telegram via API?
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