Simulink Data Explorer Extension for Visual Studio Code

Explore Simulink® models, data dictionaries, and projects directly in Visual Studio Code — no MATLAB® or Simulink installation required. Simulink Data Explorer reads .slx, .sldd, .mat, and .prj files directly, so you can browse their contents and relationships anywhere VS Code runs.

It adds a native experience for Simulink file types — a Simulink Data Explorer sidebar that maps how your models, dictionaries, and projects relate, a table editor to browse the contents of each file, and a Properties panel to inspect the selected entry — without leaving your editor. Textual (JSON) .sldd dictionaries are editable directly in the table; other formats open read-only.

Simulink Data Explorer in action: the relationship-tree sidebar and the table editor browsing a model, data dictionary, and MAT-file

Why Simulink Data Explorer?

Read Simulink files without MATLAB or Simulink — inspect .slx, .sldd, .mat, and .prj files anywhere VS Code runs, including on machines and CI agents with no MATLAB install.
See how your project fits together — a relationship tree maps every model, dictionary, and MAT-file and how they reference each other, with at-a-glance health badges for cycles, orphans, and missing references.
Click through references like hyperlinks — jump from a model to the models, dictionaries, and MAT-files it depends on in one click.
Edit textual data dictionaries in place — change values, add elements, and cut/copy/paste entries in a spreadsheet-style table, with native undo/redo and save.

Features

Navigate & understand your models

Relationship tree — a dedicated activity-bar view that scans the workspace and renders how files relate: models referencing other models, models linked to data dictionaries (.sldd) and MAT-files (.mat), and dictionaries referencing other dictionaries. Entries expand lazily as you drill in.
Jump-to-reference links — a model's Model References and External Data render as clickable links; selecting one opens the referenced model, dictionary, or MAT-file, resolved from your workspace.
Project & folder grouping — the tree groups top-level entries by MATLAB Project (.prj) or by containing folder, so files with the same name in different folders stay distinct. References resolve within a group first.
Health decorations — tree rows are badged for at-a-glance status: circular references, orphaned dictionaries/MAT-files (nothing links to them), unsaved modifications, and unresolved (missing) references.

Browse & edit file contents

Table editor — open a model, dictionary, MAT-file, or project in a spreadsheet-style, tree-structured table. Sections are always shown (e.g. a dictionary's Design Data, Architectural Data, Configurations, Other Data), even when empty.
Editing for textual .sldd — edit a textual (JSON) data dictionary directly in the table: change entry values and names, add child elements, and cut/copy/paste/delete entries via the right-click context menu. Edits write back to the JSON file, so undo/redo, the dirty indicator, and save are all native and stay in sync with the built-in text view. Binary .sldd, .slx, .mat, and .prj open read-only.
Live two-way sync — because a textual .sldd is backed by its JSON text document, edits in the table and edits in the JSON text editor update each other instantly, and there is a single shared undo history across both views.
Properties panel — a selection-following webview that shows the full properties of the entry selected in the table. It lives in its own view container and can be docked in the secondary sidebar.
Search — filter entries by name using the table's built-in filter bar as you type.

Fits your editor

Dual view for textual .sldd — because a textual .sldd is JSON, you can switch to Visual Studio Code's built-in JSON text editor at any time via Reopen Editor With….
Theme-aware — every pane follows your active Visual Studio Code color theme (light, dark, or high-contrast).

Getting Started

Install the extension. Download the latest .vsix from the Releases page, then install it either from the command line:
```
code --install-extension simulink-data-explorer-<version>.vsix
```
or from within VS Code via the Extensions view → ⋯ menu → Install from VSIX….
Open a folder or workspace that contains Simulink files.
Click the Simulink Data Explorer icon in the activity bar to see the relationship tree.
Open any supported file (.slx, .sldd, .mat, .prj) — it opens in the Data Explorer table by default. Select a row to inspect it in the Properties panel.

For a textual .sldd, you can switch to the raw JSON via View: Reopen Editor With… → Text Editor (or right-click the editor tab → Reopen Editor With…).

Supported Files

Editable in the table:

Simulink Data Dictionaries (textual) — textual (JSON) .sldd: edit values and names, add children, and cut/copy/paste/delete entries, with native undo/redo and save.

Viewing (read-only):

Simulink models — .slx
Simulink Data Dictionaries (binary) — compressed .sldd
MAT-files — .mat
MATLAB Projects — .prj

Requirements

Visual Studio Code 1.90.0 or later.

No MATLAB® or Simulink installation is required to view or edit files — Simulink Data Explorer reads and writes the files directly.

Known Limitations

Editing is supported only for textual (JSON) .sldd. Binary .sldd, .slx, .mat, and .prj are read-only.
Large textual .sldd files are limited by size. Above 50 MB, the file opens as a read-only table (VS Code cannot mirror a document that large for editing). Above 512 MB, it cannot be rendered as a table at all and opens in VS Code's built-in text editor instead.
Paste creates a new top-level entry in the target section; pasting as a child of a struct/bus is not yet supported.
Reference resolution matches files by name (basename), preferring the referrer's own project or folder. Two .prj files in the same directory are not supported.
.m files are not scanned, so a project whose members are only .m files appears as an empty group.

Questions & Answers

Do I need MATLAB or Simulink installed? No. Simulink Data Explorer reads (and, for textual .sldd, writes) the files directly, so it works anywhere VS Code runs — including machines and CI agents with no MATLAB or Simulink installation.

Which file types can I open? .slx (Simulink models), .sldd (data dictionaries), .mat (MAT-files), and .prj (MATLAB Projects). Textual (JSON) .sldd files are editable; the rest open read-only.

Can I edit files, or is this view-only? You can edit textual (JSON) .sldd dictionaries directly in the table — values, names, child elements, and cut/copy/paste/delete — with native undo/redo and save. Binary .sldd, .slx, .mat, and .prj are read-only.

A reference link doesn't open anything — why? Links resolve by file name against your open workspace. Make sure the referenced file is inside the folder or workspace you have open in VS Code; a reference to a file that isn't present shows as unresolved (and is badged in the relationship tree).

How are references matched across folders? By basename, preferring the referrer's own MATLAB Project or containing folder first. If two files share a name in different folders, the one in the referrer's group wins.

Why did my large .sldd open read-only, or as plain text? Above 50 MB, a textual .sldd opens as a read-only table (VS Code cannot mirror a document that large for editing). Above 512 MB, it opens in VS Code's built-in text editor instead of a table.

Does editing in the table stay in sync with the JSON text editor? Yes. A textual .sldd is backed by its JSON document, so table edits and text-editor edits update each other instantly and share one undo history. You can switch views anytime via Reopen Editor With….

Is my theme respected? Yes — every pane follows your active VS Code color theme (light, dark, or high-contrast).

How do I report a bug or request a feature? Please open an issue on the GitHub repository. If the extension is useful to you, a rating or review on the Marketplace helps others find it.

License

Distributed under the BSD 3-Clause License. See LICENSE for details.

MATLAB and Simulink are registered trademarks of The MathWorks, Inc. See www.mathworks.com/trademarks for a list of additional trademarks. Other product or brand names may be trademarks or registered trademarks of their respective holders.