Connectivity Middleware — Head-to-Head

Kepware vs. Ignition

Kepware and Ignition are the two most commonly co-evaluated platforms by controls engineers, but they are solving different problems. Kepware is a dedicated protocol translation and OPC server. Ignition is a full industrial application platform that handles SCADA, HMI, MES, and IIoT — with connectivity as one of its layers. Choosing between them depends on whether you need a focused connectivity tool or a platform that can anchor a broader operational architecture.

Criteria	Kepware (PTC)	Ignition (Inductive Automation)
Platform
Primary function	Protocol translation and OPC server	Industrial application platform — SCADA, HMI, MES, IIoT, connectivity
Platform scope	Connectivity only	Full operational platform; connectivity is one module
Deployment model	Windows server (KEPServerEX); Linux (Kepware Edge, in rollout)	On-premise server; edge via Ignition Edge; cloud-deployable
Licensing model	Per-driver channel or suite; costs scale with driver count	Flat-rate unlimited — unlimited tags, clients, and users on one server license
Protocol support
Driver library	150+ native drivers; deepest legacy coverage in the market	Built-in OPC-UA connects to most modern PLCs; legacy via third-party drivers or Kepware as a data source
Legacy PLC depth	Best-in-class — DH+, DH-485, DF1, S5, all major legacy protocols	Good for current-generation hardware; legacy coverage depends on third-party modules
OPC standards	OPC-DA, OPC-UA client and server	Built-in OPC-UA server; OPC-DA via legacy module
MQTT / Sparkplug B	Via third-party MQTT client plug-in	Native via Cirrus Link MQTT Transmission module; Sparkplug B support; Custom Namespace for UNS alignment
Application capabilities
SCADA / HMI	None — connectivity only	Full SCADA and HMI development environment
MES / OEE	None	Built-in OEE calculation, production tracking, recipe management
Reporting	None	Built-in reporting engine with database-driven dynamic reports
Edge deployment	Kepware Edge (Linux, in rollout)	Ignition Edge — polling and store-and-forward at the edge; limited tag count
Architecture fit
UNS architecture	Requires Cirrus Link or equivalent MQTT broker for UNS	Native UNS backbone via Cirrus Link MQTT Transmission; widely used in Sparkplug B deployments
OPC-based architecture	Best choice — purpose-built OPC server with broadest client compatibility	Strong OPC-UA server; less focused than Kepware for pure OPC integration scenarios
System integrator ecosystem	Broad; most SIs have Kepware experience	Large certified integrator network; Ignition Exchange marketplace for community modules
Procurement
Pricing	$$	$$
Watch	Kepware Edge Linux rollout ongoing — verify GA status before committing to Linux deployments	—

Protocol coverage sourced from vendor documentation. Verify driver availability for your specific device models before purchase.

Kepware wins when

Your environment has significant legacy hardware — DH+, DH-485, older Siemens — where driver field history is the deciding factor
Your architecture is OPC-DA or OPC-UA based and you need the broadest client compatibility
You need a focused connectivity tool without platform overhead
Your existing SCADA and HMI are already handled by another platform
You want to minimize the footprint of the connectivity layer

Ignition wins when

You are building or replacing a SCADA, HMI, or MES system and want connectivity bundled
You are building a UNS architecture with Sparkplug B and want native MQTT Transmission support
The flat-rate unlimited licensing model delivers better economics at scale than per-driver pricing
You need reporting, OEE calculation, or production tracking alongside connectivity
You are modernizing multiple systems simultaneously and want a single platform vendor

The real decision

These two platforms are often used together — Kepware handling legacy protocol translation and feeding Ignition as an OPC-UA client. If you are evaluating them as alternatives rather than complements, the question is scope. Kepware is the right answer if connectivity is a bounded, well-defined problem. Ignition is the right answer if you are building an operational architecture and connectivity is one piece of a larger modernization.

Licensing economics often drive the decision at scale. Kepware's per-driver model can compound significantly across a large tag count. Ignition's flat-rate model becomes increasingly attractive as the deployment grows. Run the TCO comparison against your actual tag count and site footprint before shortlisting either.