In 1944, the Bretton Woods Accord was signed, allowing currencies to fluctuate within a range of ±1% from the currency's par exchange rate. In Japan, the Foreign Exchange Bank Law was introduced in 1954. As a result, the Bank of Tokyo became the center of foreign exchange by September 1954. Between 1954 and 1959, Japanese law was changed to allow foreign exchange dealings in many more Western currencies.
Traders who understand indicators such as Bollinger bands or MACD will be more than capable of setting up their own alerts. But for the time poor, a paid service might prove fruitful. You would of course, need enough time to actually place the trades, and you need to be confident in the supplier. It is unlikely that someone with a profitable signal strategy is willing to share it cheaply (or at all). Beware of any promises that seem too good to be true.