How to Keep Mendix Pages in Sync Across Users — From Polling to Real-Time Updates

How to Keep Mendix Pages in Sync Across Users — From
Polling to Real-Time Updates

The Problem

Imagine two users, User 1 and User 2, are on the same Mendix page viewing a shared dataset — for example, a Request Overview page using Data Grid 2.

• User 1 opens a request, changes its status to Accepted, and commits.

• User 2, who is on the same page, still sees the old data.

• Unless User 2 manually refreshes the page, the update doesn’t appear.

This is one of the most common collaboration challenges in Mendix — keeping data synchronized between multiple sessions.

Understanding Why This Happens

By design, Mendix uses client-side caching and optimistic locking

• Each user session maintains its own in-memory version of objects.

• When a commit happens, Mendix updates the database but does not push changes to other active clients.

• Other users’ clients continue showing cached data until they perform an explicit refresh.

This is why User 2 doesn’t see User 1’s updates automatically.

Solution Spectrum: From Basic to Real-Time?

Let’s look at four practical ways to handle this — depending on your needs and complexity tolerance.

Auto-Refresh Using Data Grid 2 Properties (Simplest Option)

If you don’t need instant updates but you want the grid to refresh automatically without user interaction, Data Grid 2 includes a built-in feature called “Refresh interval”.

How it works

You set a time interval (e.g., 5 seconds, 10 seconds, 30 seconds).

The grid will automatically refresh the data from the database at that frequency.

Behavior

• User1 commits changes

• After the grid refreshes (within the specified interval), User2 sees the updated data automatically

• No need for microflows, web sockets, or subscriptions

Pros

• Easiest to configure

• No extra modules

• Works with database data source (no context required)

Cons

• Not real-time (only refreshes every X second)

• Frequent refresh may cause unnecessary DB load

When to use this?

Use this if:

• Real-time updates are not mandatory

• You prefer simplicity

• The grid shows overview lists (like your Request Overview page)

Scheduled Auto-Refresh Using Nanoflow Timer

If you want the page to auto-refresh periodically (every few seconds), use the Nanoflow Timer widget.

How to set up

• 1. Install Nanoflow Timer from the Marketplace.

• 2. Place it on your overview page.

• 3. Create a nanoflow NF_Refresh_RequestOverview:

• 4. Retrieve Request objects from Database

• 5. Refresh in client: Yes

• 6. Configure the timer interval (e.g., 5000 ms).

Pros

• Easy to implement

• Works for any Data Grid 2 (even database-based)

Cons

• Periodic polling, not instant

• Slight load on DB if interval is short

Real-Time Sync Using WebSocket / Notification Module

For instant updates across users — true real-time refresh.

Setup Steps

1. Install WebSocket or Notification Module from the Marketplace.

2. In your After Startup microflow → start the WebSocket server.

3. In your commit microflow (e.g., UpdateRequestStatus):

• After commit, call:

• PublishMessage(ChannelName = "RequestUpdated", Message = "refresh")

4. On your Request Overview page

• Add a WebSocket Listener widget.

• Channel: "RequestUpdated"

• On Message Nanoflow: NF_Refresh_RequestGrid

Inside NF_Refresh_RequestGrid:

If your grid is Database-based (no context):

// JavaScript action

mx.ui.reload();

Or, if it’s a microflow-based grid:

→ Re-execute that microflow → Refresh in client = Yes.

Pros:

• Real-time updates across users

• No polling

• Works for both database and microflow data sources

Cons

• Slightly more setup (server + widget config)

• Requires additional Marketplace module

Hybrid – Context-Based Smart Refresh

If you wrap your Data Grid 2 inside a non-persistent helper object,

you can refresh just that helper to re-render the grid without reloading the whole page.

Example Flow

1. Page → Data View (Helper entity) → Contains Data Grid 2.

2. When an update occurs:

• Publish "RequestUpdated".

• Listener calls nanoflow → Refresh the Helper object → Grid reloads automatically.

• Partial reload (faster).

• Slightly more model setup

Summary Table

Final Thoughts

Real-time synchronization can dramatically improve the user experience in Mendix apps — especially in collaborative environments like approvals, dashboards, or monitoring systems.

Start small with a Nanoflow Timer and move toward WebSocket-based updates when your use case demands instant visibility across sessions.