A forex signals is a suggestion for entering a trade on a currency pair, usually at a specific price and time. The signal is generated either by a human analyst or an automated Forex robot supplied to a subscriber of the forex signal service. Due to the timely nature of signals, they are usually communicated via email, website, SMS, RSS, tweet or other relatively immediate method.

Types of services

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Services provided fall into four categories:

Unpaid/free signals
Paid signals from one provider whether by personal analysis or algorithmic analysis
Paid signals aggregated from multiple signal sources or 'systems'
Signals supplied by trading software located on the trader's computer, also known as a forex robot or EA (Expert Advisor)
Typical features offered by Forex signal service providers

Typical forex-signals as provided from a renown provider.

The main services offered by forex signal suppliers are:

Exact or approximate entry, exit and stop loss figures for trades on one or more currency pairs
Supporting graphs and/or analysis for the signals
A trading history showing the number of pips profit/loss per month and/or the risk/reward ratio and actual trades. Sometimes (especially in the case of forex robots) this may be shown as back-tested results
One-on-one coaching, or additional interaction with the signal provider such as comments, forum, etc.
Account management whereby a subscriber's account can be traded by the signal provider
Educational resources either via the internet or phone
A trial period for a lesser price
Although these are the main features of a signal supplier, not all of them offer the complete list of services.