If you're trying to build a custom chat or an alert feature, getting a solid roblox messaging system script up and running is probably your top priority. It's one of those things that seems simple until you realize you have to handle cross-server communication, text filtering, and UI updates all at once. Whether you're making a global announcement system for your game or just a private messaging tool for players, the logic remains pretty similar.
Why You Need a Custom Messaging Script
Let's be honest, the default Roblox chat is fine, but it doesn't always fit the vibe of every game. Sometimes you want something that looks cleaner, or maybe you need a way for players to send "mail" to each other even when they aren't in the same server instance. That's where a custom script becomes necessary.
When you build your own system, you get total control over the aesthetics and the functionality. You can add sound effects when a message arrives, create custom chat bubbles, or even set up "admin only" channels. It gives your game that polished, professional feel that separates a hobby project from a front-page hit.
Understanding MessagingService
If you want your messages to travel across different servers—like a global shout—you have to get comfortable with MessagingService. This is the backbone of any advanced roblox messaging system script. Without it, your players are basically stuck in a vacuum, only able to talk to the handful of people in their specific instance.
MessagingService works on a "publish and subscribe" model. Think of it like a radio station. One server "publishes" a message to a specific topic, and every other server that is "subscribed" to that topic receives it. It's incredibly powerful, but you have to be careful with it. Roblox has limits on how many messages you can send per minute, so you can't just spam it every time a player moves their mouse.
Setting Up the Subscription
To start, your script needs to listen for incoming data. You'll usually do this on the server side using SubscribeAsync. This function waits for a specific "topic" (which is just a string name you pick) and then runs a function whenever a message arrives.
It's a good idea to keep your topic names unique. If you just call your topic "Chat," you might run into issues if you have multiple systems running. Use something specific like "GlobalGameAnnouncements_V1."
Publishing a Message
When a player hits "Send," your script needs to use PublishAsync. This pushes the data out to the Roblox cloud so other servers can grab it. You'll want to pass the player's name, their message, and maybe some metadata like their rank or a timestamp.
Handling Text Filtering (Don't Skip This!)
One thing you absolutely cannot ignore when writing a roblox messaging system script is text filtering. Roblox is very strict about this, and for good reason. If you let players send unfiltered text to each other, your game will likely get flagged or even deleted.
You need to use TextService to filter every single message before it's displayed to other players. Specifically, you'll be looking at FilterStringAsync. This takes the raw text and runs it through Roblox's moderation bots to replace bad words or personal info with hashtags.
A common mistake is filtering the text on the sender's side and then sending the filtered string. You should actually send the unfiltered string to the server, and then the server filters it for each recipient based on their age (Roblox handles the nuances of <13 and 13+ filtering automatically if you use the right methods).
The Server-Side Logic
Your server script acts as the middleman. The flow usually looks like this: 1. The client (the player's computer) sends a message via a RemoteEvent. 2. The server receives that event and checks if the player is allowed to talk (e.g., they aren't muted). 3. The server filters the message using TextService. 4. The server then uses MessagingService to tell all other servers about the message. 5. Every server (including the one that sent it) receives that data and tells its own players' clients to update their UI.
It sounds like a lot of steps, but once you have the boilerplate code down, it's quite reliable. The most important part is making sure your RemoteEvent is secure. You don't want exploiters being able to fire the event with someone else's name or spamming it to crash the server.
Adding a Cooldown
To prevent spam, always include a "debounce" or a cooldown on the server side. If a player tries to send ten messages in one second, your script should just ignore them. This saves your MessagingService budget and keeps the chat readable for everyone else.
Designing the User Interface
A roblox messaging system script is only as good as the UI the player interacts with. You'll need a TextBox for input and a ScrollingFrame to display the history.
Making it User-Friendly
When a new message comes in, you should automatically scroll the ScrollingFrame to the bottom. There's nothing more annoying than having to manually scroll down every time someone says something. You can do this by adjusting the CanvasPosition of the frame whenever a new child (the message label) is added.
Also, consider using UIListLayout. This is a lifesaver for organizing messages. It handles all the spacing and positioning for you, so you just have to parent the new message label to the frame and it snaps into place.
The Client-Side Script
The client-side script is mostly responsible for the "fluff." It detects when the player presses the "Enter" key in the TextBox, fires the RemoteEvent, and clears the box so they can type again. It also listens for the server telling it that a new message has arrived so it can create a new text label and display it.
Common Pitfalls to Avoid
Even experienced devs trip up when working on a roblox messaging system script. One major issue is the "Echo Effect." If you aren't careful, the server that sends the message might try to process it twice—once when the player sends it and once when it receives its own MessagingService update. You usually want to filter out the message on the sending server so the sender sees their message instantly, but the global update doesn't create a duplicate.
Another thing to watch out for is data limits. MessagingService messages have a size limit (around 1KB). This is plenty for a simple string of text, but if you try to send a massive table of data with dozens of variables, it might fail. Keep your "payload" lean. Send the player's UserId instead of their whole name and all their stats. You can always look up the name from the ID on the receiving end.
Taking it Further: Private Messaging
If you want to move beyond global chat and into private messaging, things get a bit more complex. You'll need a way to specify a recipient. Instead of publishing to a general "GlobalChat" topic, you might publish to a topic named after the recipient's UserId.
Each player's client could subscribe to a topic specifically for them. This is a great way to handle "Whispers" or trade requests. Just remember that the same filtering rules apply! Just because it's "private" doesn't mean it doesn't need to be moderated.
Testing Your Script
Testing a roblox messaging system script can be a bit of a headache because you can't really test MessagingService in a solo Studio session. You'll need to open a "Local Server" with at least two players or, better yet, publish the game and join it with a friend (or a secondary account).
Check for latency. Sometimes there's a slight delay between one server sending a message and another receiving it. This is normal, but if it's taking more than a second or two, you might need to look at how you're handling your subscriptions.
Final Thoughts
Creating a custom roblox messaging system script is a bit of a rite of passage for Roblox developers. It forces you to learn about server-client communication, cloud services, and the importance of game security.
Don't get discouraged if your first attempt results in a bunch of red errors in the output console. Messing up the logic of MessagingService happens to the best of us. Just keep your code organized, always filter your strings, and make sure you aren't hitting those rate limits too hard. Once you get it working, you'll have a much more interactive and dynamic world for your players to enjoy.