IronPLC

Note: This extension is published under two different names because the two registries are separate namespaces:

Visual Studio Marketplace — listed as IronPLC IDE (extension ID ironplc.ironplc-vscode)

Open VSX — listed as IronPLC (extension ID ironplc.ironplc), used by Cursor, Kiro, Devin (formerly Windsurf), and VSCodium

Direct VSIX from GitHub Releases

Both listings are the same extension. In Cursor, IronPLC works in the Cursor IDE interface; it is not available in Cursor's newer agent-first interface.

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

Install the IronPLC compiler and extension
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

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.