IronPLC

Note: The IronPLC VS Code extension is currently unavailable on the Visual Studio Marketplace. Install via:

• Open VSX (Cursor, Windsurf, VSCodium)
• Direct VSIX from GitHub Releases

Existing installs continue to work; automatic updates from the Marketplace are paused. We are working with Microsoft to restore the listing.

IronPLC provides IEC 61131-3 Structured Text language support for VS Code. Get real-time error checking, syntax highlighting, and build tools for PLC programs — no proprietary IDE required.

Quick Start

1. Install the IronPLC compiler and extension
2. Open or create a .st file and start coding

See the quick start tutorial to write your first PLC program.

Capabilities

• Real-time diagnostics — syntax and semantic errors reported as you type
• Syntax highlighting — Structured Text and PLCopen XML files
• Build and run — compile and execute programs from the editor
• Bytecode viewer — inspect compiled programs

Works with Structured Text (.st, .iec) and PLCopen XML files, including the PLCopen XML-based .TcPOU, .TcGVL, and .TcDUT formats.

Learn More

• Documentation
• Playground
• Troubleshooting
• Source

Trademarks

IronPLC is an independent open-source project. It is not affiliated with, endorsed by, or sponsored by any third party. TwinCAT is a trademark of Beckhoff Automation GmbH & Co. KG. CODESYS is a trademark of CODESYS GmbH. PLCopen is a trademark of PLCopen. All other trademarks are the property of their respective owners. References to these names in this extension are descriptive only — they indicate file formats and compatibility modes that the extension can read.