Microsoft Deprecates Polyglot Notebooks & Faces User Backlash | .NET Interactive Future Uncertain

Microsoft has announced the deprecation of Polyglot Notebooks, a Visual Studio Code (VS Code) extension that allowed developers to write and execute code in multiple programming languages within a single notebook environment. The move, announced on February 13th, 2026, effectively ends active development and support for a tool popular with data scientists and those working with mixed-language workflows.

The deprecation comes with just over a month’s notice, with full deprecation scheduled for March 27th, 2026. According to Claudia Regio of Microsoft’s Platform and Tools team, bug fixes and support will cease immediately, and issues related to the extension – including its use as a kernel in other Jupyter frontends – will be closed.

Polyglot Notebooks distinguished itself by supporting a wide range of languages, including C#, F#, PowerShell, JavaScript, SQL, and KQL (Kusto Query Language). The extension had garnered significant adoption, boasting over 1.8 million installs and a four-star rating in the VS Code marketplace. Its appeal stemmed from its ability to seamlessly blend these languages within a single interactive environment, a capability powered by .NET Interactive.

The decision to discontinue Polyglot Notebooks raises questions about the future of .NET Interactive itself. While Microsoft has not explicitly commented on the project’s overall trajectory, the extension’s reliance on .NET Interactive suggests a potential impact. The deprecation also arrives alongside the retirement of Azure Data Studio (ADS) at the end of February 2026, adding complexity to the situation for users who relied on both tools.

Initially, Microsoft positioned Polyglot Notebooks as a key replacement for ADS’s SQL + Markdown notebook functionality, particularly for data analysts. However, the company has since reversed that recommendation, leaving users searching for alternative solutions. Randolph West, a Microsoft technical writer, stated he was “legally bound to remove that recommendation” following the Polyglot Notebooks announcement, acknowledging the lack of a clear alternative. He also expressed personal fondness for ADS, stating, “I’m just as big a fan of Azure Data Studio as you are.”

The abruptness of the announcement and the lack of a readily available replacement have drawn criticism from the developer community. One Reddit user lamented, “This is a disaster for us. We use polyglot Notebooks for all our data science courses. All the people saying do not trust or rely on Microsoft were sadly right again.” Another user questioned the reasoning behind the deprecation and the short timeframe, highlighting the disruption it would cause to existing workflows.

Microsoft has suggested C# file-based apps, a feature introduced in .NET 10, as a potential alternative. This feature allows C# files to be executed without the need for a full project setup. However, many users argue that this is not a comparable solution, particularly for the prototyping and demonstration capabilities offered by Polyglot Notebooks. As one commenter noted, “Polyglot notebooks are incredibly useful for prototyping stuff and demoing. Almost hard to believe that something so unique and useful is getting killed off like that.”

The situation is further complicated by the perceived shortcomings of the SQL Server extension for VS Code, which Microsoft is promoting as a replacement for ADS. Reviews of the SQL Server extension reveal user frustration, with comments describing it as “riddled with bugs” and a less polished experience compared to ADS. One user pointedly asked, “how is a tool that worked fine (ADS) being discontinued and this is being recommended as the alternative?”

Despite the user backlash, Microsoft maintains its commitment to C# development. Regio stated, “While Polyglot Notebooks may be deprecated, our mission to make C# development delightful and accessible continues in our flagship products; we’re carrying that work forward through C# Dev Kit and the next generation of AI-powered coding experiences.” However, it remains to be seen whether these efforts will adequately address the needs of users who have come to rely on the unique capabilities of Polyglot Notebooks.

The deprecation of Polyglot Notebooks underscores the challenges of maintaining and supporting niche development tools within a large software ecosystem. While Microsoft’s stated goal is to focus resources on core products and future innovations, the decision has left a segment of the developer community feeling abandoned and searching for viable alternatives.