Rapid control prototyping (RCP) is a widely used technique for verifying a controller's functional behavior. Typically, RCP uses a target processor with ample processing power and memory, which makes the technique attractive for engineers exploring new concepts. However, a large gap often exists between the RCP target and the production ECU in terms of the available code generation technology, the supporting tool chain, and I/O hardware. Consequently, significant work is required when migrating a controller from RCP to production. Furthermore, due to cost constraints, RCP systems are difficult to deploy in large numbers for fleet testing or preproduction trials.In response to the challenges associated with RCP, automotive engineers are moving towards a technique called on-target rapid prototyping (OTRP). With OTRP, the code is generated, cross-compiled, and downloaded either to the ECU used in production or a development version of it with additional memory and instrumentation support. OTRP enables engineers to use the same code generator, supporting tool chain, and ECU hardware during development, simplifying the migration to production. In addition, due to the relatively low cost of development ECUs, OTRP systems can be deployed in large quantities.This paper provides an introduction to Model-Based Design and OTRP, a step-by-step approach for getting started with OTRP using a new algorithm export technique, and considerations for moving from OTRP to production. An application example is provided to illustrate how OTRP has been effectively used for a production-intent ECU program, which includes a novel external mode implementation on a resource constrained fixed-point embedded system.