What is the max length of a Python string?

With a 64-bit Python installation, and 64 GB of memory, a Python 2 string of around 63 GB should be quite feasible. If you can upgrade your memory much beyond that, your maximum feasible strings should get proportionally longer. But this comes with a hit to the runtimes.

With a typical 32-bit Python installation, of course, the total memory you can use in your application is limited to something like 2 or 3 GB (depending on OS and configuration), so the longest strings you can use will be much smaller than in 64-bit installations with very high amounts of RAM.