There is no single best language for industrial robot arms — the right answer depends on the brand of controller, and whether the job calls for vendor-specific motion programming or cross-platform integration. Each major manufacturer ships its own proprietary language tied to its hardware, while open-source and Python-based tools exist specifically to work across those languages rather than replace them. For a reader choosing where to invest learning time, the practical split is between native vendor languages (fastest and most reliable for motion on that one brand) and broader languages like Python and C++ (used for cross-vendor simulation, planning, and integration work). The sections below break down what each language is for and when it actually makes sense to learn it.
Table of Contents
- What language does each major robot brand actually use?
- Why learn Python or C++ instead of a vendor language?
- How does RoboDK's Python API change the equation?
- What about the PLC logic that coordinates the robot cell?
- Which language should a specific reader choose?
- Frequently Asked Questions
What language does each major robot brand actually use?
Every major industrial robot maker builds its own controller language, and none of them are interchangeable. ABB's controllers run RAPID, a language included with every ABB controller and structured similarly to Visual Basic. KUKA's robots use KRL, a Pascal-like language that also runs a second "advance run" program counter to handle motion blending between points. FANUC's controllers use KAREL, also Pascal-based, typically alongside simpler teach-pendant programs that handle the added logic, according to RoboDK and IndustrialMonitorDirect's robot-brand comparisons and a KUKA Robot Language reverse-engineering paper.
The pattern holds beyond the "big four." Yaskawa Motoman arms run INFORM, Comau uses PDL2, Kawasaki uses AS, and Stäubli uses VAL3 — four more proprietary languages, each locked to its own hardware, according to industrial robot programming lecture notes. None of these languages works on a different brand's controller without a translation layer. Universal Robots, a maker of collaborative robot arms ("cobots") designed to work alongside humans, follows the same model with its own language, URScript. Universal Robots states that URScript was developed in-house to directly control its cobot arms, and that any sequence built visually in its PolyScope graphical interface gets translated into URScript before it runs on the robot, according to Universal Robots' own developer documentation. So even a "no-code" teach-pendant program is, underneath, running the vendor's native language.
Why learn Python or C++ instead of a vendor language?
If the goal is working across multiple robot brands rather than mastering one controller, Python and C++ are the more useful investment. The open-source Robot Operating System (ROS), written primarily in C++ and Python, was extended for factory use by ROS-Industrial, a project founded by Southwest Research Institute, Yaskawa Motoman, and Willow Garage. ROS-Industrial provides drivers for common industrial manipulators, grippers, sensors, and device networks under a permissive BSD license, according to ROS-Industrial's official project description. That cross-vendor reach didn't arrive all at once.
When the driver program launched in 2013, it already covered ABB, Fanuc, Motoman, and Universal Robots arms, but KUKA, Comau, and Kawasaki still needed community-built drivers to catch up, according to a 2013 ROS.org announcement of the ROS Industrial Consortium Driver Program. This matters for anyone evaluating ROS-Industrial today: coverage for a given brand should be checked directly rather than assumed, since it grew organically rather than launching complete. MoveIt 2, the standard ROS 2 framework for planning robot arm motion, reflects the same C++/Python split by design rather than by accident. It offers a C++ API recommended for complex, performance-sensitive applications, alongside a Python binding called moveit_py aimed at rapid prototyping, according to MoveIt's own documentation. A developer building a production work cell leans on the C++ API; one testing an idea quickly reaches for Python.
How does RoboDK's Python API change the equation?
For engineers who need to program robots from several different manufacturers without learning seven separate languages, RoboDK offers a Python API that simulates and generates native programs for industrial arms across brands from one codebase. It is explicitly positioned as a way to avoid writing in each vendor's own language directly. Siemens's current RoboDK product page claims support for more than 1,200 robot models from over 80 manufacturers, according to Siemens's RoboDK product page.
In practice, this means a RoboDK script written in Python can target an ABB arm one day and a FANUC arm the next, with RoboDK handling the translation into RAPID or KAREL behind the scenes. For integrators managing mixed-brand factory floors, that translation layer removes the need to maintain separate codebases per vendor — though the underlying robot still ultimately executes its own native language. ROS-Industrial's Descartes tool, released in 2015, serves a related but more specialized purpose: it plans under-defined Cartesian tool paths for process tasks like painting, grinding, and welding, built on top of ROS's C++/Python stack rather than any single vendor's language, according to Control Engineering's coverage of ROS-Industrial. This is motion planning for a class of tasks, not a general substitute for a vendor's controller language.
What about the PLC logic that coordinates the robot cell?
A robot's motion program is only part of what runs a work cell. The programmable logic controller (PLC) that handles cell I/O and safety interlocks typically runs under a completely different standard: IEC 61131-3, which defines five standardized PLC languages — Ladder Diagram, Function Block Diagram, Structured Text, Instruction List, and Sequential Function Chart.
First published in 1993 and now in its third edition from 2013, IEC 61131-3 governs the logic that often coordinates a robot cell's inputs, outputs, and safety systems, but it does not define robot motion programming itself, according to a Control.com technical overview of the standard. This is a distinction worth keeping straight when staffing or scoping a project: the person writing RAPID or KRL for arm motion and the person writing Structured Text for cell safety logic are often working in entirely separate language families, even on the same production line.
Which language should a specific reader choose?
The right choice depends on the task in front of the reader, not a universal ranking: A reader working at a single-brand integrator or OEM gets the most immediate value from the vendor's own language, since that is what the hardware actually executes. A reader building tools, research platforms, or multi-vendor deployments gets more value from Python and C++, since those are what the cross-platform layer — ROS-Industrial, MoveIt 2, and RoboDK — is built on.
- Programming motion on one specific brand's robot — learn that brand's native language: RAPID for ABB, KRL for KUKA, KAREL for FANUC, INFORM for Yaskawa Motoman, PDL2 for Comau, AS for Kawasaki, VAL3 for Stäubli, or URScript for Universal Robots.
- Building or integrating across multiple robot brands — learn Python and C++ through ROS-Industrial and MoveIt 2, or through RoboDK's Python API if native-program generation across brands is the goal.
- Prototyping or testing motion planning ideas quickly — Python, via moveit_py or RoboDK's scripting interface.
- Building performance-critical, production-grade motion applications in ROS — C++, via MoveIt 2's primary API.
- Coordinating cell-level I/O, interlocks, and safety logic around the robot — one of the five IEC 61131-3 PLC languages, most commonly Structured Text or Ladder Diagram.
Frequently Asked Questions
Can one language program robots from every manufacturer?
Not directly. Each brand's controller executes its own native language — RAPID, KRL, KAREL, INFORM, PDL2, AS, or VAL3 — so cross-brand work relies on tools like RoboDK's Python API or ROS-Industrial to generate or translate into those native languages.
Does learning Python replace the need to learn a vendor's robot language?
No. Python-based tools like RoboDK and MoveIt 2's moveit_py still generate or send commands that ultimately run as the robot's native language on its controller; Python replaces writing that native language by hand, not the language itself.
Is PLC programming the same as robot arm programming?
No. PLCs that coordinate a robot cell's safety and I/O typically run one of the five IEC 61131-3 languages, which is a separate standard from any robot manufacturer's motion-programming language.
