EMA crossover with an RSI filter: the classic trend-following setup for XAUUSD

The EMA crossover is the first strategy most traders try when they start algo trading — not because it is magical, but because it is unambiguous enough that a machine cannot misread it. This article covers the structure, the parameters worth tuning, and the mistakes that make backtests look great while live results bleed.

The framework

• Base signal: fast EMA (20) crossing above the slow EMA (50) → short-term momentum beats the medium-term trend → consider Buy. Crossing below → consider Sell.
• RSI filter: only Buy when RSI(14) > 55, only Sell when RSI < 45. RSI here is not for picking tops and bottoms — it confirms strength and keeps you out of choppy crossings.
• Exits: fixed SL (typically 200–300 points on XAUUSD M15), TP at a 1:2 risk-reward ratio, with breakeven once profit reaches half the SL.

The edge is not the win rate (usually 35–45%) — it is small losses, big winners: one strong gold trend pays for many small stops.

Four parameters worth tuning (and two to leave alone)

Parameter	Try	Note
EMA pair	20/50, 21/55, 9/21	Faster = more signals, more noise
Timeframe	M15, H1	M5 and below is noisy on gold
RSI thresholds	55/45, 60/40	Tighter = fewer, better trades
SL	200–350 points	ATR-based is even better

Two things you should not over-optimize: TP (keep it as an R:R ratio) and the RSI period (14 is fine — 13 vs 15 is curve-fitting).

Why pretty backtests fail live

1. Using the running candle: crossover signals must be evaluated on closed candles (index 1 and 2). Using candle 0 produces flickering signals — invisible in backtests, constant in live trading.
2. No session filter: gold chops through the Asian session and loves fake crossings there. Restricting to London + New York improves trade quality significantly.
3. Ignoring spread: XAUUSD spread runs 20–35 points. With a 100-point SL, spread eats a quarter of your stop — an SL that tight is self-sabotage.
4. Both directions at once when position count is uncapped — cap it at 1 position while you are starting out.

How to describe this to the AI

Cover four things: entry (EMA pair + RSI thresholds, closed candles), exits (SL in points, TP as R:R, breakeven), sizing (% risk or fixed lot), filters (sessions, max positions). Don't make the AI guess — anything you leave out gets a safe default, documented in the bot profile.