Question

I want to interact with a Photoshop file and create images using its actions and smart objects.

Is there any php or C# API to can do it?

Answer 1

This sound like hard but some companies seems to make it work. Xee can read PSD too (and has an epic comment about this format in the source code).

But to quote someone over at HN:

PSD was never intended to be a data interchange format: it is the
serialization format of a single program that has more individual
unrelated features that actual people rely on than almost any other
piece of software and has maintained striking amounts of backwards
compatibility and almost unbroken forwards compatibility during its
over two decades of existence. This product’s “file format” needs to
be critiqued in this context, along with similar mega-programs like
Office. I am thereby having a difficult time fathoming why anyone
would think that a PSD file is thereby going to be some well-organized
file format that they should easily be able to parse from their own
application is just naively wishful thinking: even other products
from Adobe have limitations while opening these files; to truly
manipulate these files you really need to be highly-compatible with
Photoshop’s particular editing model (hence the conceptual
difference between these two classes of file format).

I would recommand to look at Xee for a server side utility.

Good luck.