origo

There are a lot of people using the very same algorithms for trading, and still make money.

Using a simple EMA crossover signal with RSI and volume support is quite sufficient to make lots of good trades, one big reason being the fact that a lot of traders actually use the very same indicators, and self-fulfilling the prophecy.

It takes more than just reading a few indicators to consistently trade successfully, but my point is that many 'algorithms' and 'trading systems' only really work when they are well known.

There's never a very 'reliable way' to backtest, as any interaction you would have done with the market is not accounted for. If you intend to trade (very) low volume it might work decently (on longer timeframes). Existing (open source) and my own home-made backtester use tweaks like slippage to try and 'simulate' this market interaction.. A few I have seen actually use tick-by-tick L2 data to try and get closer to the 'truth'. IMHO, the only really reliable way to evaluate a trading algorithm is to trade it live. This will cost you money, unless you get everything perfect the first time, but doesn't any kind of passive income generation require an initial investment? And yes, I have written, and currently operate, my own (quite basic) trading bot. Yes, it's profitable.