Do I need any special hardware to start developing embedded applications for the Nordic Thingy?

[ScreenName321123]

I have a Nordic Thingy:52 and Nordic Thingy:91, and I want to develop custom embedded software for them. Do I need a J-TAG or can I flash code using USB?

I've seen tutorials that show how to flash code using west, since I want to use BLE (and LTE on the Thingy:91), I'll probably need Zephyr, but the Zephyr doHcumentation says that flashing Zephyr requires an external J-Link programmer. 

How would I be able to get started with C or C++ development for the Thingys?

[Menon]

Hello,

You can program both platforms by using the nRF connect desktop-->Porgrammer. Take a look into this page from nordic as a starting point.

Kind Regards,

Abhijith