FIX API order types are the instructions a trader uses to control how an order is executed — at what price, how completely, and under what conditions. This page explains the main FIX API order types, how they compare with the order types in MT4 and MT5, and how lot size and trading volume work, since both are common sources of confusion.
Resposta Rápida: FIX API trading supports market, limit, stop, and stop-limit orders, plus execution conditions such as Immediate or Cancel (IOC) and Fill or Kill (FOK). Compared with MT4, FIX API gives finer control over how an order fills; MT5 is closer to FIX API in capability. FIX API Terminal also lets traders apply Limit IOC and Limit FOK conditions to manage slippage.
What Are FIX API Order Types?
An order type defines how the market should handle your instruction to buy or sell. The choice of order type decides whether you prioritise speed of execution or control over price, and whether a partial fill is acceptable. In FIX API trading, order types and execution conditions are sent as standardized FIX messages, which gives the trader precise, explicit control over execution.
The Main FIX API Order Types
Market order. A market order executes immediately at the best price currently available. It prioritises certainty of execution over price, which means it can be exposed to slippage if the price moves between sending and filling.
Limit order. A limit order executes only at a specified price or better. It gives the trader control over price, but it may not fill at all if the market never reaches the limit.
Stop order. A stop order becomes a market order once the market reaches a trigger price. It is commonly used for stop-loss protection and for breakout entries.
Stop-limit order. A stop-limit order becomes a limit order — not a market order — once the trigger price is reached. It combines a trigger with price control, so the fill cannot happen worse than the limit.
Alongside the order type, the trader also sets a time in force — how long the order stays active — such as Day or Good-Till-Cancelled (GTC).
Execution Conditions: IOC and FOK
Two execution conditions are central to FIX API trading because they let a trader control how completely an order fills.
Immediate or Cancel (IOC). An IOC order fills as much as possible immediately, at the price or better, and cancels any remaining unfilled part. Partial fills are accepted.
Fill or Kill (FOK). A FOK order must fill immediately and in full, at the price or better, or be cancelled entirely. Partial fills are not accepted.
These conditions are usually applied to limit orders, producing a Limit IOC ou Limit FOK order. Both bound the execution price, which makes them a practical tool for controlling slippage: instead of accepting an unknown market price, the trader sets the worst acceptable price and accepts the possibility of non-execution in return.
FIX API Order Types vs MT4 and MT5
A frequent question is how FIX API order types compare with what MT4 and MT5 offer. The table below is a general comparison.
| Order type / condition | MT4 | MT5 | FIX API (FIX API Terminal) |
|---|---|---|---|
| Market order | Yes | Yes | Yes |
| Limit order (buy/sell) | Yes | Yes | Yes |
| Stop order (buy/sell) | Yes | Yes | Yes |
| Stop-limit order | No | Yes | Yes |
| Stop Loss / Take Profit | Yes | Yes | Yes |
| Imediato ou Cancelar (IOC) | Not exposed to the trader | Yes (fill policy) | Yes (per order) |
| Preencher ou matar (FOK) | Not exposed to the trader | Yes (fill policy) | Yes (per order) |
| Convert a robot’s market orders to Limit IOC / FOK | No | No | Yes |
In short: MT4 covers the basic order types but does not give the trader stop-limit orders or per-order IOC/FOK control. MT5 is considerably closer to FIX API — it adds stop-limit orders and exposes IOC and FOK as fill policies. The clearest FIX API advantage is not a longer list of order types but the directness of execution and the ability, in FIX API Terminal, to apply Limit IOC or Limit FOK to the orders an MQL robot generates without changing the robot’s code.
Understanding Lot Size and Trading Volume
Order types decide how an order executes; lot size decides how large it is. Lot sizing confuses many traders, so it is worth setting out clearly.
What Is a Lot?
A lot is a standardized unit of trade size. In Forex, lot size is measured in units of the base currency — the first currency in a pair. Trade size is then expressed as a multiple or fraction of a standard lot.
Standard, Mini, and Micro Lots
| Lot type | Units of base currency | Common notation |
|---|---|---|
| Standard lot | 100,000 | 1.0 |
| Mini lot | 10,000 | 0.1 |
| Micro lot | 1,000 | 0.01 |
| Nano lot (broker-dependent) | 100 | 0.001 |
The size of a lot also determines the value of a pip. On a standard lot of a US-dollar-quoted pair, one pip is worth roughly $10; on a mini lot roughly $1; on a micro lot roughly $0.10. So a trader who reduces lot size from 1.0 to 0.1 reduces both the position size and the per-pip profit or loss by a factor of ten.
How Volume Is Expressed in FIX API Trading
This is where many traders lose their footing. In a standard retail platform, you usually enter volume as a lot figure such as 1.0 or 0.1. In FIX API trading, the volume field in a FIX order message may be expressed differently depending on the broker’s FIX specification — some brokers expect the number of lots, others expect the actual number of units of the base currency. A “1” in one broker’s FIX setup is not necessarily the same size as a “1” in another’s. Before trading live, always confirm from the broker’s FIX API documentation how the volume field is defined, so a position is the size you intend.
Lots Beyond Forex: Metals, Indices, and CFDs
The word “lot” does not mean 100,000 units outside Forex. For metals, one lot of gold is commonly 100 troy ounces; for index CFDs, the contract size per lot varies by instrument and broker. Because contract size differs, the most reliable way to think about size across asset classes is notional value — contract size multiplied by price multiplied by the number of lots. This is the same notional-value approach used to calculate fees, explained on the FIX API Terminal pricing page.
How FIX API Terminal Handles Order Types and Lots
FIX API Terminal supports market, limit, stop, and stop-limit orders, along with IOC and FOK execution conditions, all sent as standard FIX messages to the broker. It can also apply Limit IOC or Limit FOK conditions to the orders generated by an MQL robot, in fully automated mode and without changing the robot’s code, which helps traders control slippage. For volume, FIX API Terminal works with the broker’s FIX specification — so confirming how that broker defines the volume field remains an important first step.
Perguntas Frequentes
What order types does FIX API support?
FIX API trading supports market, limit, stop, and stop-limit orders, along with execution conditions such as Immediate or Cancel (IOC) and Fill or Kill (FOK), and time-in-force settings such as Day and Good-Till-Cancelled.
What is the difference between IOC and FOK orders?
An IOC (Immediate or Cancel) order fills as much as possible immediately and cancels the rest, so partial fills are accepted. A FOK (Fill or Kill) order must fill immediately and in full or be cancelled entirely, so partial fills are not accepted.
Do MT4 and MT5 support the same order types as FIX API?
MT4 covers market, limit, and stop orders but not stop-limit orders or per-order IOC/FOK control. MT5 is closer to FIX API: it adds stop-limit orders and exposes IOC and FOK as fill policies. FIX API additionally allows converting a robot’s market orders to Limit IOC or Limit FOK.
What is a lot in Forex trading?
A lot is a standardized trade size. In Forex, a standard lot is 100,000 units of the base currency, a mini lot is 10,000 units, and a micro lot is 1,000 units.
What is the difference between a standard, mini, and micro lot?
A standard lot is 100,000 units of base currency (notation 1.0), a mini lot is 10,000 units (0.1), and a micro lot is 1,000 units (0.01). Pip value scales with lot size — roughly $10, $1, and $0.10 per pip respectively on a US-dollar-quoted pair.
How is trading volume expressed in FIX API trading?
It depends on the broker’s FIX specification. Some brokers express the volume field in lots, others in actual units of the base currency. Always confirm the definition in the broker’s FIX API documentation before trading live.
Does lot size work the same way for metals and indices?
No. Outside Forex, a lot represents a different contract size — for example, one lot of gold is commonly 100 troy ounces. The most consistent way to compare size across asset classes is by notional value: contract size multiplied by price multiplied by lots.
Conclusão
FIX API order types give traders explicit control over how an order executes, and IOC and FOK conditions add control over how completely it fills. MT5 is fairly close to FIX API in raw order-type capability, while MT4 is more limited. Understanding lot size — and confirming how each broker expresses volume — is just as important as choosing the right order type.
Baixe a plataforma de negociação FIX API gratuita Aprenda como funciona o trading com a FIX API