Sendbird No-Token Connect: 3 Critical Mistakes to Avoid

What is Sendbird's No-Token Connect?

Sendbird's Chat SDK offers a powerful suite of tools for building real-time communication features. To get developers up and running quickly, Sendbird provides a simplified connection method known as No-Token Connect. As the name implies, it allows a client-side application to connect to the Sendbird backend using only a userId, bypassing the need for a session token or access token.

This feature is a fantastic accelerator for development, prototyping, and internal testing. It removes the initial friction of setting up a token authentication server, letting you jump straight into building UI and testing chat functionality. However, this convenience comes with significant security trade-offs. Treating No-Token Connect as a permanent solution or misconfiguring its environment can lead to severe vulnerabilities. This article explores the three most critical mistakes developers make when using this feature and how to avoid them to ensure your application is both functional and secure.

Why These Mistakes Are So Critical

It's easy to dismiss development-phase settings as temporary, but these specific mistakes have lasting consequences. Failing to manage No-Token Connect properly can expose your application to:

• Critical Security Breaches: Allowing unauthorized users to impersonate others and access private conversations.
• Data Integrity Nightmares: Creating thousands of "ghost" users that don't exist in your primary database, making user management impossible.
• Service Abuse: Opening the door for spam bots and malicious actors to overwhelm your chat service, leading to poor performance and potential suspension.

Understanding these pitfalls is the first step toward leveraging Sendbird's tools safely and effectively, from the first line of code to your production launch.

Mistake #1: Using No-Token Connect in a Production Environment

This is the cardinal sin of Sendbird integration and the most dangerous mistake you can make. No-Token Connect is explicitly designed for non-production environments. Pushing it live is equivalent to leaving the front door of your house wide open.

The Glaring Security Gaps

Without token-based authentication, the only thing needed to access a user's account is their userId. Since user IDs are often predictable (e.g., sequential numbers, usernames, or email prefixes), a malicious actor can easily write a script to impersonate any user on your platform.

Imagine a user with the ID "john_doe_123". With No-Token Connect enabled in production, anyone can initialize the Sendbird SDK with that ID and gain full access to John's private channels, messages, and metadata. There is no server-side verification to stop them.

Real-World Consequences

The fallout from this mistake can be catastrophic:

• Account Takeovers: Malicious users can take over legitimate accounts, read their private messages, and send messages on their behalf.
• Data Leaks: Sensitive information shared in one-on-one or private group chats can be exfiltrated.
• Spam and Abuse: Attackers can programmatically connect as various users to spam your entire user base.

The Correct Approach: Token-Based Authentication

The industry standard for secure client-server communication is token-based authentication. In Sendbird, this means:

1. A user logs into your application's backend.
2. Your secure server verifies their credentials and uses the Sendbird Platform API to generate a short-lived, unique session token for that specific userId.
3. Your server sends this token to the client.
4. The client uses this token to connect to Sendbird: SendbirdChat.connect(userId, sessionToken, ...).

This flow ensures that only authenticated users from your trusted backend can obtain a valid session token, effectively closing the impersonation loophole. Always disable "Allow connections without a token" in your Sendbird dashboard before going to production.

Mistake #2: Ignoring Dashboard Security Settings

Even when using No-Token Connect correctly in a development environment, it's a mistake to think all other security measures can be ignored. Sendbird provides several dashboard-level security features that act as a crucial safety net. Neglecting them exposes your development application to abuse, which can disrupt your team's work and skew test data.

Unconfigured Domain & IP Filters

Sendbird allows you to restrict access to your application based on the request's origin. These are your first line of defense:

• Domain Filtering (for Web): You can specify a whitelist of domains (e.g., localhost, dev.myapp.com) that are allowed to initialize the SDK. This prevents someone from copying your application ID and using it on a malicious website.
• IP Whitelisting (for Platform API): Restrict which server IP addresses can make calls to the Platform API. This is critical for securing server-to-server actions like user creation and moderation.

Failing to configure these leaves your dev environment open to anyone on the internet who discovers your Application ID.

Overlooking Rate Limits

Rate limits prevent a single user or IP address from overwhelming your application with requests. While default limits are in place, understanding and monitoring them is key. If your development application is public-facing (e.g., a TestFlight build or a staging website), a bot could still connect and hit your API endpoints repeatedly, potentially impacting performance for your entire development team.

Mistake #3: Mismanaging User Creation and Lifecycle

Often used in tandem with No-Token Connect is the setting to "Allow user creation on SDK connection." When enabled, if a client tries to connect with a userId that doesn't exist in your Sendbird application, Sendbird will automatically create a new user with that ID. While this seems convenient for testing, it's a direct path to data chaos.

The "Ghost User" Problem

This setting decouples user creation in Sendbird from user creation in your application's primary database. A developer testing a feature might connect with a random ID like "test_user_123". This creates a permanent user in Sendbird but not in your backend.

Over time, your Sendbird user base becomes littered with these "ghost users"—remnants of tests, typos, and automated scripts. This pollutes your data, makes it impossible to reconcile your Sendbird user list with your actual user database, and can even lead to you paying for a higher user count than you actually have.

Scaling and Data Integrity Nightmares

When you eventually move to production, this becomes a massive problem. You'll have a Sendbird application full of users who shouldn't exist, and you'll have no reliable way to clean them up without potentially deleting legitimate users. It complicates moderation, user lookups, and analytics. Starting with a clean, controlled user creation process is essential for scalability.

Best Practice: Server-Side User Creation via Platform API

The correct and scalable way to manage users is to treat your own backend database as the single source of truth. The workflow should be:

1. A user signs up for your service.
2. Your backend server successfully creates the user record in your primary database.
3. Immediately after, your server makes a call to the Sendbird Platform API to create a corresponding Sendbird user with the same userId.

This ensures that every user in Sendbird has a corresponding, legitimate entry in your system. Always disable "Allow user creation on SDK connection" and manage your user lifecycle exclusively through the Platform API from your secure backend.

Conclusion: Connect Securely and Smartly

Sendbird's No-Token Connect is a sharp tool, perfect for accelerating the initial phases of development. But like any sharp tool, it demands respect and understanding. By avoiding these three critical mistakes, you can harness its speed without falling victim to its risks.

Remember the golden rules: never use No-Token Connect in production, always layer your security with dashboard settings like domain filters, and maintain data integrity by managing users from your backend via the Platform API. By following these principles, you'll build a secure, scalable, and robust chat experience that you can launch with confidence.