what is this

Scaffold / Scaffolding

"Platform" is not wrong and would be understood by an English speaker as a generic term for a raised structure you stand on. But the more specific term for that object is a "scaffold" or "scaffolding." If you think "scaffolding" seems like it should be a verb (given the "-ing"), you are correct in your instincts, but it is actually a noun. English includes a lot of quirks and inconsistencies. Usage varies, but in general "scaffold" refers to a single temporary platform component, like in the picture you posted, but when multiple scaffolds are put up they are collectively the "scaffolding." You posted a picture of a scaffold. When you see a bunch of those around a building, that's the scaffolding.

Others have said it’s scaffolding so I’ll just point you to wordreference.com because its translations are more reliable

Is it bad I thought this was one of those loft beds? (I think they are called, whatever bunk beds with no bottom beds are.) Thought it was one without the mattress.

Scaffolding - specifically 'zip up scaffolding', because of the pre-made 'legs'.

Scaffolding…as a construction worker, these things give me nightmares.

Platform is not inaccurate but Scaffolding the more precise term. ˈskæfəldɪŋ https://en.m.wiktionary.org/wiki/scaffolding

Agreed that scaffold/scaffolding (or even scaff) is correct here. "Platform" would just refer to the board on top that you walk on.

That is a scaffold. The complete set of scaffolds connected together to allow workers to reach high places, is called the scaffolding.

Scaffolding

I'd call it a work platform.

I'd call it a scaffold tower. To me scaffolding is more the larger semi permanent structures, not the mobile towers. 

That is a scaffold, specifically double scaffolding, masonry scaffolding, or freestanding scaffolding, as it is self-supported. A unit of scaffolding, in this case two frames and two crossbars (the Xs), is called a "buck" of scaffolding. So it I was setting up scaffolding 3 units tall, I might say I need "3 bucks of scaffolding" and if I needed a walkway on the bottom, such as by a sidewalk, the base layer would be "walk-thru scaffolding," which is taller, and allows a person to walk under without climbing or ducking. The walkable section on top is called a "platform", "walk-board," or A standard section of scaffolding is about 5' tall, or 1.5M, while a walk-thru scaffolding is 6'4-6'7 tall or about 2M tall. We use this for my work, we have about 30 sections of it I can see in the warehouse right now.

https://en.m.wiktionary.org/wiki/andamio

baker

Scaffold, but you can call it a platform only if there's enough context.

Idk what this is even my in my native language lol

Clearly, you've never played Minecraft