EA setfiles and input settings explained
Every Expert Advisor has inputs, the settings that control how it trades. A setfile (.set) is a saved set of those inputs. Understanding the common ones helps you use an EA safely.
What a setfile is
A setfile is a small text file with the values for all of an EA's inputs. Sellers ship one so you can start from the recommended configuration instead of typing every value.
Load and save a setfile
Attach the EA to a chart, open the Inputs tab and click Load to choose a .set file. Click Save to store your own version. Keep a copy of the original so you can always go back to the recommended values.
Common inputs
Names differ from EA to EA, so read the user manual, but most EAs share these ideas.
- Lot size or risk percent: how large each trade is. Fixed lot is simple; risk percent sizes trades from your balance and stop distance.
- Magic number: an ID that lets the EA recognise its own trades. Use a different one for each EA or chart so they do not interfere.
- Stop loss and take profit: the exit distances, often in points. Remember that on 5-digit brokers a pip is 10 points.
- Max spread: the EA skips new trades when the spread is wider than this value.
- Max slippage (deviation): the largest price difference you accept between the requested and the filled price.
- Trading hours or session filter: restricts trading to certain times. Check the time zone it uses, usually broker server time.
- Max open trades or max drawdown stop: caps exposure.
Change one thing at a time
If you adjust inputs, change one at a time and test on a demo account first. Large changes to risk settings are the most common way to turn a tested configuration into an untested one.
Frequently asked questions
Do I have to use the setfile?
No, but it gives you the seller's recommended starting values. Without it the EA runs on built-in defaults, which may differ.
What is a magic number?
A number the EA stamps on its trades so it can tell them apart from manual trades and from other EAs. Each EA instance should use its own.
Why does the EA not open trades?
Common causes are Algo Trading switched off, spread above the max spread input, trading hours outside the allowed session, or a lot size outside the broker's minimum and step.
Trading foreign exchange, gold and CFDs carries a high level of risk and may not be suitable for all investors. Past performance, backtests and live results do not guarantee future returns. This guide is general education, not financial advice.