Many people have doubt over the difference between Application Dev and Software Engineer Role at Udaan
This post will try to clear doubt as much possible -

Application development is a different org than software engineering, and it was newly introduced to ramp up velocity of work.
currently they have changed the requirements of software engineer as 6+ yoe

for AD you are directly working with a SE/PE so he is kind of the guy responsible for the final product
and you are coding it up but obvously an AD can take part in decisions about the product.
So as AD you get to work end to end and with discussion with SE.

But SE defines/approves the design choice or reviews the design you made
as he is final responsible for design of the end product.

So at the end handling SDLC of the product is the core responsibility of a SE but he also codes like AD.

Here being a startup culture, you are not restricted to contrinute, if you are willing you are welcome.
After all SE listens to AD's thinking, takes suggestion, its open ended here, and you are the owner of the part you are handling.

And one of the major difference is Salary obviously, SE having much more experience gets a lot more than AD in most cases.