What is Sim App?

In the computer aided engineering environment, a Sim App or Simulation App is a type of web application (or web app) which enables a purely browser based access (no client side resident software) to a simulation model or simulation workflow. Being a web app, a Sim app provides similar benefits in terms of modest local processing requirements and greatly enhanced accessibility. But the primary function of a sim app is to democratize the normally complex simulation and modeling process, and to do so with existing software tools rather than developing bespoke systems.


Simulation for design and analysis has historically required substantial expertise and familiarity of the software being used, and very often multiple software tools had to be run within a workflow, further raising the difficulty. Sim apps emerged to remove this constraint and make simulation both more efficient and more broadly usable for oft repeated design processes.


A sim app is a system with two primary components, one for the client side exposed to the user, and the other on the server side, to control the process..

  1. Client side – a browser based user interface that is fit-for-purpose. Most simulation software is general in nature, modeling for example fluid flow or material stresses, but a fit-for-purpose user interface is very specific with only applicable inputs, options, terminology and the like. To accomplish this, user interaction is conducted via a custom configured web interface.
  2. Server side (backend or host), most often on a corporate internal network or in a cloud facility, here the system must be able to drive the software or workflow, performing the process automation function. To do this, the server side system must also be able to manage file and data access, handling, storage, etc. and ensure repeatablilty.

Thus, the sim app is effectively a “wrapper” that encloses and runs the software workflow, and user access is no longer direct to the underlying software but rather indirectly, through a separate web interface.


Sim apps are best suited to oft repeated type applications, as the effort to build one must be balanced with the frequency of use and life cycle of the tool.

  • 3d simulation such as CFD or FEA or a standard component or process that requires some level of modification for different requirements
  • an input/output calculator. These may be based, for example, on models built with Excel, MATLAB, or Mathcad.
  • In-house or legacy software lacking a modern user interface, for example a FORTRAN code

Learn more about Sim Apps in these references and examples: