{
    "products": [
        {
            "slug": "open62541",
            "name": "open62541",
            "kind": "resource",
            "website": "https://open62541.org/",
            "page": "https://listme.name/software/open62541",
            "tagline": "Open-source C library that implements the OPC UA standard",
            "summary": "open62541 is an open-source implementation of OPC UA (IEC 62541) written in C99 and licensed under the Mozilla Public License 2.0. The library runs on Windows, Linux, RTOS and Android and is built to run from embedded systems to cloud servers.",
            "platforms": [
                "windows",
                "linux",
                "android"
            ],
            "pricing": "open-source",
            "free_to_use": true,
            "open_source": true,
            "license": "MPL-2.0",
            "source": "https://github.com/open62541/open62541",
            "strengths": [
                "MPL-2.0 licensed, with the source public on GitHub",
                "Runs on Windows, Linux, RTOS and Android",
                "Written in C99 with minimal dependencies for embedded targets"
            ],
            "limits": [
                "Needs C programming, since it is a library rather than a gateway"
            ],
            "checked": "2026-10-10",
            "connected_to_publisher": false,
            "overview": "open62541 is a C library, so developers build OPC UA servers and clients on top of it rather than configuring a gateway. The project ships example server and client implementations, and its README describes a platform-independent design in which platform-specific code lives in exchangeable plugins. Porting to new embedded targets is meant to be done through those plugins.\n\nThe README reports zero issues from Valgrind, DrMemory and AddressSanitizer runs and from OSS-Fuzz fuzzing. The source is public on GitHub under MPL-2.0. The trade-off is effort: teams write the application code in C, and new hardware needs architecture-specific plugins."
        },
        {
            "slug": "prosys-opc-ua-gateway",
            "name": "Prosys OPC UA Gateway",
            "kind": "app",
            "website": "https://prosysopc.com/products/opc-ua-gateway/",
            "page": "https://listme.name/software/prosys-opc-ua-gateway",
            "tagline": "Migrates classic COM-based OPC servers to OPC UA on Windows",
            "summary": "Prosys OPC UA Gateway is a Windows application that wraps classic COM and DCOM OPC servers as OPC UA servers. It supports OPC UA, OPC DA 2 and 3, OPC AE and OPC HDA, and connections can be added at runtime without a restart. It is licensed, and the vendor offers a trial.",
            "developer": "Prosys OPC",
            "platforms": [
                "windows"
            ],
            "pricing": "paid",
            "price_note": "Licensed software; trial offered and prices in the vendor price list",
            "free_to_use": false,
            "open_source": false,
            "strengths": [
                "Migrates legacy COM OPC servers to OPC UA",
                "Runs on 32-bit and 64-bit Windows",
                "Connections can be added at runtime"
            ],
            "limits": [
                "Pricing sits in a separate price list",
                "Windows is the only platform listed"
            ],
            "checked": "2026-10-10",
            "connected_to_publisher": false,
            "overview": "Prosys OPC UA Gateway is built for migrating classic COM and DCOM OPC servers to OPC UA. The product page describes it as a high-performance wrapper and proxy built on the vendor's C++ OPC UA server and client toolkit, and says it can be configured through OPC UA methods.\n\nIt runs as a 32-bit Windows application that also works on 64-bit Windows, and it supports OPC UA, OPC DA 2 and 3, OPC AE and OPC HDA. The page points to a separate price list for licensing details and offers a trial. The gateway suits sites that must keep legacy OPC clients running while they move to OPC UA. Because it targets classic OPC servers, it is not a driver product for new PLCs."
        }
    ],
    "differences": [
        "Only open62541 runs on Linux.",
        "Only open62541 runs on Android.",
        "open62541 is open source; Prosys OPC UA Gateway is not.",
        "open62541 has a free plan or free version; Prosys OPC UA Gateway does not.",
        "open62541: free and open source. Prosys OPC UA Gateway: paid."
    ],
    "shared_rankings": [
        {
            "list": "opc-and-industrial-connectivity-software",
            "name": "OPC and industrial connectivity software",
            "page": "https://listme.name/best/opc-and-industrial-connectivity-software",
            "of": 10,
            "results": [
                {
                    "product": "open62541",
                    "rank": 8,
                    "score": 77.5,
                    "verdict": "Free MPL-2.0 OPC UA library in C99 that runs on Windows, Linux, RTOS and Android. It suits developers who write their own servers and clients, and it is not a configurable gateway or a client tool.",
                    "best_for": "Developers building OPC UA servers and clients in C",
                    "spec": {
                        "protocols": "OPC UA (IEC 62541)",
                        "license_model": "Open source under MPL-2.0",
                        "trial": "Not needed; source is free"
                    }
                },
                {
                    "product": "prosys-opc-ua-gateway",
                    "rank": 6,
                    "score": 79,
                    "verdict": "Wraps classic COM OPC DA, AE and HDA servers as OPC UA servers, with runtime connection changes. It is a 32-bit and 64-bit Windows application, and pricing sits in a separate price list.",
                    "best_for": "Migrating legacy COM OPC servers to OPC UA",
                    "spec": {
                        "protocols": "OPC DA 2/3, OPC AE, OPC HDA to OPC UA",
                        "license_model": "Licensed; price list on the site",
                        "trial": "Trial offered"
                    }
                }
            ]
        }
    ],
    "ranks_higher_in_closest_shared_list": "prosys-opc-ua-gateway",
    "page": "https://listme.name/compare/open62541-vs-prosys-opc-ua-gateway",
    "json": "https://listme.name/api/v1/compare/open62541-vs-prosys-opc-ua-gateway.json",
    "notes": [
        "Scores are editorial and only comparable inside one list. Products with connected_to_publisher true receive a disclosed ranking lift: https://listme.name/methodology"
    ],
    "source": "https://listme.name",
    "license": "Free to read and cite with attribution to listme.name.",
    "docs": "https://listme.name/developers"
}