RBX Viewer
Inspect Roblox places and models as readable XML without leaving Visual Studio Code.
RBX Viewer is a read-only, local-first VS Code custom editor for Roblox model/place files. It understands the Roblox binary container and displays its decoded hierarchy and supported properties as an XML diagnostic view. New or unknown property encodings are retained and clearly marked, allowing the rest of a valid file to open.
Supported files
| Extension |
Input format |
Viewer behavior |
.rbxl |
Binary place (v0) |
Decode hierarchy/properties to diagnostic XML |
.rbxm |
Binary model (v0) |
Decode hierarchy/properties to diagnostic XML |
.rbxlx |
Roblox XML place |
Show original XML source |
.rbxmx |
Roblox XML model |
Show original XML source |
.rbxl / .rbxm containing legacy Roblox XML |
XML |
Detect content and show original XML source |
Binary support includes INST/PROP/PRNT/META/SSTR chunks, LZ4/Zstandard compressed chunks, known Roblox property value encodings (including SecurityCapabilities), and defensive detection of newer property types. Unknown types are not guessed: the full decompressed property-chunk payload is stored as Base64 under RBXViewerOpaqueProperties, with a warning and its type ID, property, and class metadata.
Important: Binary-derived XML is a diagnostic representation, not a guaranteed Roblox Studio-importable .rbxlx / .rbxmx file. RBX Viewer does not support editing, saving changes back to Roblox binary, or lossless round-trip conversion.
Open a Roblox file
- Open
.rbxl, .rbxm, .rbxlx or .rbxmx in VS Code.
- Right-click its editor tab and select Reopen Editor With... → RBX Viewer. Optionally configure RBX Viewer as the default editor for the extension.
- Or right-click a file in Explorer and select RBX Viewer: Open as XML.
- Use Find, Copy XML, Open Full XML (the built-in VS Code text editor), Save XML As... and Reload.
VS Code's Open Anyway button invokes the built-in text editor, not RBX Viewer; use Reopen Editor With... for binary files.
The preview is capped at 2,500 lines by default for responsiveness. Open Full XML exposes the complete generated XML with VS Code's native folding and search.
Safeguards and privacy
- All parsing happens locally in a cancellable, time-limited worker thread; no uploaded files, analytics, network calls, remote scripts, or Roblox Studio installation required.
- The source files are never modified by the viewer. XML export explicitly chooses a different destination.
- Untrusted XML values are rendered as text nodes, not executable HTML. The webview has a restrictive Content Security Policy.
- Configurable input, decompression, XML-output, instance-count and preview limits guard against oversized files. The defaults are intentionally conservative.
- Unknown binary property types and some incompatible property layouts are preserved for inspection, not silently interpreted as correct values. Corrupted headers, parent relationships and unsupported container versions still fail safely.
Compatibility and limitations
- Roblox's binary format is undocumented/subject to change. Newly introduced property encodings can be retained as opaque Base64, but their semantic values cannot be shown until supported.
- Unknown non-property container structures, new compression schemes or container versions may not open; preserving individual PROP chunks does not guarantee support for future whole-file formats.
- Noncanonical diagnostic output is not an interchange format for Roblox Studio. Use Roblox Studio's own export for an importable
.rbxlx / .rbxmx.
- XML files are encoding/root-checked, not fully schema-validated. RBX Viewer does not execute Luau contained in Roblox models.
The decoder was exercised with synthetic binary/XML fixtures and a real .rbxl place supplied during development (83 instances, 1,309 decoded property chunks and one retained unknown chunk). Compatibility with every Roblox Studio release and Marketplace-wide user environment is not guaranteed.
License
MIT. See LICENSE.
