Who actually trades in the order book: bots, MMs, and the human's place

Opening the order book, you are not looking at a "market of people": the overwhelming majority of quotes and trades on liquid pairs are generated by algorithms. Understanding their roles means understanding who you are playing against.

The book's ecosystem

• Market makers: professional firms quoting both sides for the spread. Useful (without them the book is empty), but their algorithms instantly pull quotes on news - "liquidity disappears when it is needed".
• Arbitrageurs: they level prices between venues and between spot and futures. Thanks to them the price is "the same" everywhere - and any "inefficiency" is guaranteed to be eaten before you reach it.
• Execution algorithms: fund robots slicing large orders into invisible pieces (TWAP/VWAP). That is the "whale" you never see in the tape.
• Predators: stop hunting, spoofing (fake walls), momentum ignition. Against them - healthy skepticism toward "obvious" levels and walls.

The human's place

Competing with bots on speed is a guaranteed loss. Human advantages lie on a different timescale: theses spanning weeks, understanding narratives, patience, and the ability not to trade. Scalping against algorithms is an expensive hobby; positional play by your own plan is territory where latency does not decide.