Previously we discussed tools for developers that you can install on your machine.
Here we will cover some online tools that are essential for developers in many ways and help you build stuff faster.
stackexchange network is your best buddy, open an account there and participate so you can learn and help others learn . Reputation over there can be useful in getting online jobs too.
Use github to host your opensource applications.
Do learn regex on preference as it will make a lot of your tasks simpler in the long run, regex101 can help you achieve that faster by helping you test your regex with explanation. Regex will help you do complex text filtering and conversions in your app by writing single lines of codes which otherwise would need a separate routine / function.
Make sure to check out documentation of the language you are developing and search it to find exactly what you are looking for. Initially the documentation looks technical and difficult to understand but in the long run, you will find it more convenient to check it as it is usually very to the point and technically correct for that specific framework / language.
use pastebin to paste codes that you want to share.
If you want quick access to already built material for your side, envato network is useful in getting hold of a decent item. Its good to let your client chose themes directly in some cases so they know what choices they had.
Use a decent cloud service to cater to your hosting and other online needs.
You may try koding if you like the idea of having an online ide instead of one installed on your computer, however it is useful only in some rare cases.
use a tool like jsfiddle to test your code and share with others online.
fontawesome is useful in providing a nice collection of symbols using a font.
diffchecker to find differences between two files if you are going online.
Trello or wunderlist for online task management for yourself or with your team.