Server-side trailing stop vs EA-managed trailing: slippage differences

[FXS London Scalper]

MT4/MT5 have a built-in trailing stop, but it runs on the client terminal, not the server. If the terminal closes, trailing stops. EAs that trail stops also run client-side and modify the server-side stop.

Some brokers offer genuinely server-side trailing stops (via their own platform or API). The question is whether this affects slippage.

How each works:
- Client-side trailing (MT4/MT5 built-in or EA): the terminal watches price and sends a modify request to move the stop. The stop itself sits on the server.
- Server-side trailing: the broker's server moves the stop. No modify requests needed.

Slippage considerations:
- When the stop triggers, it becomes a market order in both cases. Slippage depends on market conditions, not on how the stop was moved.
- Client-side trailing can lag: the modify request takes time, and in fast markets the stop might not move before price reverses.
- Too many modify requests may hit rate limits or freeze levels.

So server-side trailing doesn't reduce slippage at the trigger, but can keep the stop more up to date.

Anyone compared both on the same strategy?