What is the MRT file format?
An .mrt file is an XML-based report template created by Stimulsoft Designer, a reporting tool for .NET, Java, and web-based applications developed by Stimulsoft. The file stores the complete design of a report - page layouts, data bands, text fields, table structures, database connection strings, and formatting rules - as a UTF-8 XML document.
The XML root element is typically <StiReport>. A version attribute in the root records the Stimulsoft release that created the file; the format evolves with each product version but maintains backward compatibility across recent releases.
At runtime the Stimulsoft rendering engine processes the .mrt template and produces output in formats such as PDF, HTML, Excel, Word, and CSV, without modifying the source file. The .mrt is a design artifact, not a rendered document.
Because .mrt templates often embed database connection strings, files should be treated as potentially sensitive - credentials may be stored in plain text within the XML. Files containing embedded images can reach several megabytes in size.
Stimulsoft Designer is available as a free web-based tool that opens and edits .mrt files without a paid license, as an installed desktop application, and as a component SDK for embedding in custom .NET or Java applications. The product targets .NET 6+, .NET Framework, Java, JavaScript, Angular, and React runtimes.
Security & safety
RISK: MEDIUMMRT files are XML and cannot execute code directly. However, they often contain database connection strings with embedded credentials (server addresses, usernames, passwords). Treat received .mrt files as potentially sensitive configuration artifacts. Do not share them publicly.
Format details
in a nutshell- Microsoft Visio 2010 Installation Archive - Microsoft used .mrt internally during Visio 2010 setup; these are proprietary installer temp files not meant for end-user use.
- MikroTik RouterOS Remote Test File - MikroTik's The Dude network monitoring tool saves bandwidth test results as .mrt files.
- Hyper-V Modifiable Region Table - Windows Hyper-V uses .mrt files internally to track dirty regions of virtual disk checkpoints.
Programs that open MRT files
Windows3 apps
Stimulsoft Designer (web)
Freemium Go to designer.stimulsoft.com → Open → upload the .mrt file to view/edit without installing software.
Stimulsoft Reports (installed)
Paid Open Stimulsoft Designer installed component → File → Open → select the .mrt file.
Visual Studio / VS Code (text editor)
Free Open as XML in any text editor to inspect structure; not human-readable without Stimulsoft tooling. 
macOS1 app
Linux1 app
Technical details
deep spec| Encoding | UTF-8 XML (plain text) |
| XML root element | <StiReport> (or Stimulsoft-specific variant) |
| MIME type | application/xml |
| Version tracking | Version attribute in XML root; evolves with each Stimulsoft product release |
| Output formats | PDF, HTML, Excel, Word, CSV, RTF, and others - rendered at runtime; .mrt stores the design only |
| Design-time artifact | .mrt is a design template only; the rendered output is a separate file produced at runtime |
| Typical file size | 10 KB-5 MB (larger files contain embedded images) |
| Platform support | Windows, Linux, macOS via .NET 6+, .NET Framework, Java, JavaScript, Angular, React |
| Security consideration | Database connection strings (possibly including credentials) may be stored in plain text in the XML |
| Free tooling | Stimulsoft Designer (web-based) opens and edits .mrt files without a paid Stimulsoft license |
| Data binding model | Data sources and connection parameters defined in template; actual data is resolved at render time |
| Supported components | Report bands, sub-reports, cross-tab tables, chart components, rich text fields, barcodes |
| Released | Early 2000s (Stimulsoft Reports product line) |
| Latest version | Stimulsoft Reports 2026 (format continuously evolved) |
| Specification | www.stimulsoft.com |
MRT conversions
Community Q&A
asked by usersNo questions yet - be the first to ask about MRT files.
