system
Given the following post, respond as if you're commenting on Reddit:
human
[Marvel] So is the bifrost just a teleaporter? How fast is the bifrost? How does it work?

From the movies it seems to be a quick zap and your there. Does heimdall just think of a place and your there?
gpt
Per the first Thor movie it creates a wormhole, an Einstein-rosen bridge. When Thor transports Jane to Asgard and when Sif arrives on earth in Agents of Shield you can spot the actual wormhole that the beam travels through if you look carefully. It's not really a teleporter because that would (traditionally) imply travellers are disassembled and then reassembled at their location.  Seems more like a super fast space lift or a cannon. It shoots a beam through the fabric of space that travellers can then pass through (and even get knocked out of).

It seems to be nigh-instantaneous, only taking a few seconds for each trip. Since it opens wormholes "speed" might not be all that important.

Heimdall just thinking is essentially how it works in the comics (well, he has to dip his hand in it), but the MCU version seems more technical so there's probably some sort of mechanism there. It seems primarily focused on the 9 realms, but according to Thor: Ragnarok it seems, at least theoretically, capable of reaching anywhere.

And according to the Thor. the Dark World prequel comic it was originally powered (or at least constructed) by the "allfather's power", however you want to interpret that. After it was broken in Thor 1 it was repaired by the Tesseract.