How to get it from the mouth of a horse? redex on github
Just in case, the connection is broken in the future:
How does this compare with ProGuard?
ReDex is conceptually similar to ProGuard, as both optimize bytecode. ReDex, however, optimizes .dex bytecode, while ProGuard optimizes the .class bytecode before it is omitted to .dex. Working .dex is sometimes an advantage: you can consider the number of virtual registers used by the method that is the candidate for insertion, and you can control the location of the classes in the dex file. But ProGuard has a lot that ReDex does not (for example, ReDex does not remove unused method parameters that ProGuard does).
In our opinion, comparing ReDex and ProGuard is a bit apples and oranges as we focused on the optimizations that add on top of ProGuard. We use both tools to optimize the Facebook application. Our performance and size indicators (about 25% on dex size and cold start time) are based on using ReDex in an application already optimized using ProGuard. We do not plan to measure performance without ProGuard.