ECN vs STP vs market maker: what the account label means for your EA

Labels first, mechanics second

Compare ECN vs STP vs market maker accounts on a broker's website and you will see three columns with ticks and crosses. The labels are not regulated terms, so two brokers can mean different things by the same word. What you can pin down is the mechanism each label is supposed to describe, and what that mechanism does to an Expert Advisor's fills.

All three sit on top of the book model described in A-book vs B-book. Market maker is a B-book description; ECN and STP are A-book descriptions; and most real accounts are hybrids wearing whichever label sells best.

Market maker: the dealing desk

A market maker, or dealing desk broker, quotes its own prices and takes the other side of your trade. The classic offer is a fixed spread, say 2 pips on EURUSD, no commission, and fills at the quoted price. Because there is no external counterparty, the broker can fill instantly and without slippage, or it can requote, widen or delay, depending on how it is run.

For an EA the fixed spread is a real advantage in one respect: the cost per trade is known in advance, so a backtest with a fixed 20-point spread is at least honest about the spread. The disadvantages are that 2 pips is expensive for a scalper, and that the broker's risk management is invisible to you.

STP: straight through, with a mark-up

Straight-through processing means the broker passes your order to one or more liquidity providers without a dealing desk intervening, which is why STP is often sold under the NDD (no dealing desk) badge. The broker earns by adding a mark-up to the provider's spread. If the provider shows 0.3 pips on EURUSD, the broker might show you 1.2 pips and keep the difference.

In practice an STP account feels like a variable-spread account with no commission. Spreads are tight in busy hours and widen at rollover and on news. Fills come from the provider, so slippage is real and usually symmetric: sometimes you get a better price, sometimes worse. Some brokers STP only part of the flow and keep the rest, which brings you back to the hybrid model.

ECN: raw spread plus commission

An electronic communication network account connects you to a pool of participants, banks, other brokers and sometimes other clients, and matches orders against the best available price. The broker adds nothing to the spread and charges a commission instead. A typical raw spread account on a major pair shows 0 to 0.3 pips most of the day and charges around $6 to $7 per standard lot round trip, though the commission varies a lot between brokers.

The total cost is often lower than STP for a liquid pair in liquid hours, and higher for an illiquid pair or at 23:00 server time, when the raw spread can be wider than an STP account's marked-up one. The headline of a zero spread account is true only for the seconds when the best bid equals the best ask; the commission is always there.

Because the matching is competitive, fills can be partial on large sizes, and the depth of market in MT5 shows real liquidity at each price level. For a 0.1-lot forex robot that depth is irrelevant; for a 20-lot one it is the whole story.

Matching the account to the EA

The right account is the one whose cost structure sits where the strategy is least sensitive.

• Scalping and high-frequency trading bots: ECN or raw spread, almost always. A 2-pip fixed spread eats a strategy whose average winner is 5 pips. Check that the broker does not restrict the minimum distance for stops and pending orders, which some dealing desks do.
• Intraday trend and breakout EAs with 20 to 50-pip targets: STP or ECN both work; the difference is a few points per trade. Look instead at slippage behaviour at session opens.
• Swing and position EAs: spread model is almost irrelevant. Swap is the cost that matters, and it is set by the broker independently of the account label. Compare the nightly figure with the swap cost calculator.
• Grid and martingale EAs: no account type makes these safe, but a commission-based ECN account makes their true cost visible on every trade, which is a good thing for the person reading the record.

Reading the account type off a track record

A verified account page does not print the account label, but the evidence is all there. The Execution quality section shows the spread profile per symbol in points, sampled live, and the trade table shows commission and swap per trade when the owner exposes those columns. A tight, variable spread with a non-zero Comm. column is an ECN or raw account; a tight spread with zero commission is STP; a flat spread profile through the whole day with zero commission is a fixed-spread market maker.

Then compare the record's cost structure with yours. An EA with a 40-point average winner on a 9-point ECN account has a cost ratio near a quarter. Move it to a 20-point fixed-spread account and the ratio is a half; the same strategy now has a much thinner edge. The slippage cost calculator and pip value calculator turn the points into money at the lot sizes you would use, and broker cost audit covers the full method.

Things the label does not tell you

A few details matter more than the three-letter badge and are rarely on the comparison table.

• Execution type: market execution fills at the best available price; instant execution fills at the requested price or requotes. EAs built for one can misbehave on the other.
• Minimum stop distance and freeze level, which decide whether a tight-stop scalper can place its orders at all.
• Maximum lot per order and maximum number of orders, which cap a grid or a large account.
• Whether swap is charged in points, in currency or as a percentage, and how Wednesday's triple swap is handled.
• The account's MT5 position mode, netting or hedging, covered in netting vs hedging accounts.

Related reading

The account label decides the shape of your costs; spreads, commissions and swaps explained puts numbers on each one. To see how those costs land on real EAs, open any verified account on Rankings and read its Execution section alongside the trade table.