Pony is an object-oriented, capabilities-secure, high-performance programming language. That’s a lot of hyphens in a short space. What makes Pony different is the high number of guarantees that compiling a Pony program will give you.
Pony programs are type-safe and memory-safe, without any unchecked exceptions. Pony also gives you a feature called reference capabilities. That means if your program compiles, it might do the wrong thing (if you have logic errors), but you won’t have crashes. Pony’s compiler also guarantees that concurrent programs won’t have data races or deadlocks.
Because Pony has some innovations including copy-free message passing and a powerful garbage collector, it’s extremely fast and excellent at concurrency.
In 2010, Sylvan Clebsch was working on a flight simulater and later distributed applications. The same problems kept popping up so he started working on a C-runtime to fix them. He found that while creating the library was possible, it was difficult to make sure that the clients of that library were fulfilling all of the obligations that would make his code safe and secure.
After doing quite a bit of research, he later abandoned that effort and formed a small team to shift to a language. Pony was created in 2014 and opensourced in 2014. By this time, a larger team was working with it.
The primary innovations were around the garbage collection model and a couple of language features called reference capabilites and object capabilities. These features allowed Sylvan and the Pony team to provide more and more guarantees by the compiler.
You can read more at the early history of Pony article.