We are happy to share that online migration in the Azure DocumentDB Migration extension for VS Code is now Generally Available. Back in November 2025, we launched the Public Preview and since then, many customers have put it through its paces with all kinds of MongoDB workloads. Based on what we learnt from those real migrations (the issues they hit, the edge cases they uncovered, the feedback they shared), we went back and made the tool significantly more resilient, more usable, and better performing. This GA release is the result of that work.
What Is the Azure DocumentDB Migration Extension?
If you are running MongoDB and want to move to Azure DocumentDB, this extension is for you. It sits right inside VS Code, so there is no need to set up separate tools or deploy any infrastructure. You can assess your workload, pick which databases and collections you want to migrate, and run the whole thing from one place. It supports online migration, which means your application can keep running while the data moves over with near-zero downtime.
What Changed Since Public Preview?
For this release, we focused on making sure the extension works the way you expect it to. We dug into the failures customers were seeing, the edge cases that would trip up long-running migrations, and the rough spots in the experience. The work fell into three areas: handling scale, improving reliability, and making the whole experience smoother.
Handling Scale and Network Complexity
This was the biggest area of work. During preview, we found that customers with very large collections or a large number of collections were running into issues. We reworked the migration engine to handle these scenarios properly. If you have hundreds of collections or collections with tens of millions of documents, the tool now handles it reliably.
We also expanded private endpoint support. Many customers have complex network setups involving hub-spoke topologies, multiple virtual networks, and firewall rules. Connecting to the source MongoDB cluster was not always straightforward in these environments. The extension now supports a wider range of these network configurations out of the box.
Reliability Improvements
The retry and checkpoint logic was already there in preview, but we found several edge cases where it did not work as expected. Transient network drops, partial batch commits, and intermittent source unavailability would sometimes leave the migration in a bad state. We have gone through these scenarios one by one and fixed them. Migrations now resume cleanly from where they stopped.
The change stream sync phase also got a lot of attention. Cursor expiration, resume token issues, and long gaps in source activity could all break the sync earlier. We have hardened this path so that data consistency is maintained even if the migration runs over extended periods.
Usability
The dashboard UI was struggling with large migrations. When you had hundreds of collections, the polling would become sluggish and sometimes unresponsive. We optimised the data fetching to keep things smooth regardless of how many collections you are migrating.
Error messages have also been improved. Earlier, when something went wrong, the errors were sometimes too generic to be useful. Now they are more specific, with pointers to the relevant documentation so you can actually diagnose and fix the problem.
Performance
The bulk copy phase is noticeably faster now. We tuned the batching, improved parallelism, and made better use of the managed migration backend resources. The change stream sync also processes events with lower latency, which means the gap between your source writes and the target catching up is smaller. This gives you more confidence when you are ready to do the final cutover.
How It Works
The migration still works in two phases, same as before:
- Initial Bulk Copy moves the bulk of your data to Azure DocumentDB.
- Change Stream Sync picks up all the inserts, updates, and deletes happening on the source in real time and applies them to the target. This keeps both sides in sync until you decide to cut over.
What is different at GA is that both phases are now more robust and faster. You can monitor the progress from the dashboard and do the cutover when you are comfortable.
Getting Started
Open VS Code, go to Extensions, search for “DocumentDB”, and install the Azure DocumentDB Migration Extension. The wizard walks you through the setup step by step. There is no cost and no additional infrastructure to deploy. Everything runs on managed resources in Azure.
Wrapping Up
If you have been waiting for the migration tool to be production-ready before committing to it, this is the release to try. We have put in the work to make it handle real-world migrations reliably, whether you have a handful of collections or hundreds of them.
Give it a go and check out the documentation and FAQ if you need help getting started.
About Azure DocumentDB
Azure DocumentDB is a fully managed document database service for building and modernizing MongoDB-compatible applications. Powered by the open-source DocumentDB engine, it combines familiar APIs, tools, and workflows with Azure’s security, scalability, and operational simplicity. Whether you’re developing new applications or migrating existing MongoDB workloads, Azure DocumentDB helps you get started quickly and scale with confidence.
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