There are a few new smartphone apps that can be quite helpful to travelers. And chances are you don’t know about them.

There’s Timeshifter, and it’s all about beating jet lag. You type in your departing and arriving times and airports, and then an algorithm sets an hourly schedule telling you when to nap as well as when to drink coffee.

GlobeTips helps travelers going abroad, where Americans usually…overtip. This app tracks tipping practices in more than 200 countries and regions.

And then there’s Crime and Place — the app that — as its name implies — tells you where not to go when you’re traveling.