Vetting Rules are described with a simple text-based language.

The basic form of a rule is result if condition, such as:

fail if order.side is Bid and order.value > balance.amount

Rules can be placed inside blocks, so they are only evaluated if a condition is met, such as:

run if order.side is Bid
        fail if order.value > balance.amount

Rules can provide a result code, allowing more visibility of which vetting rule was matched.

fail with InsufficientShares if order.side is Ask and order.quantity > holding.shares

Rules can be disabled, or documentation recorded, by using the # symbol

# This is not a rule, just a comment

fail if order.value > balance.amount # Comments can go after rules

# The following rule will not be evaluated
# fail with DisabledRule if a = b


Rules are evaluated one by one, from start to finish. Evaluation starts with an intermediate result of pass.

When the condition for a Rule is met, the result is applied to the intermediate result in the following manner:

  • pass leaves the result unchanged.
  • auth replaces pass.
  • fail replaces pass or auth.

When all rules are evaluated, vetting supplies the final result, along with the result codes from all matching rules.


A condition consists of one or more comparisons to perform that, when true, cause a rule to match.

Binary Conditions

Binary conditions are operations between two values, such as equals =, greater than > or less than <.

The Vetting Engine supports the following operators:

Operator Description Example
= Equals order.side = 'Buy'
is Equals (shorthand) order.side is Buy
<> or != Not Equal balance.currency <> 'AUD'
is not Not Equal (shorthand) balance.currency is not AUD
> Greater Than order.value > 10000
>= Greater Than or Equal order.value >= 10000
< Less Than order.value < 10000
<= Less Than or Equal order.value <= 10000

There are also a set of operators with special requirements:

Operator Description Example
has Does a property exist holding has quantity
missing Is a property missing holding missing quantity
in Is the value one of a list, or part of a string order.type in ['Limit', 'MarketToLimit']
not in Is the value not one of a list, or not part of a string 'I' not in symbol.attributes.Flags

Unary Conditions

Unary conditions are operations performed on a single value, such as not.

The Vetting Engine supports the following operators:

Operator Description Example
not Not not (order.side = 'Buy' and order.value > 100)

Combining Conditions

Conditions can be combined using boolean operators such as and.

fail if order.side is Bid and order.value > balance.amount

The Vetting Engine supports the following operators:

Operator Description Example
and Match if both sides match order.value > 100 and order.value < 1000
or Match if either side matches order.value > 100 or balance.currency is AUD
xor Match if only one side matches balance.amount > 1000 xor balance.currency is AUD

Conditions can also be organised using parenthesis.

fail if (order.side is Bid and order.value > 100) or (order.side is Ask and order.quantity > 200)

Representing Values

There are two types of values used by the Vetting Engine: pre-defined values, and vetting properties.

Pre-Defined Values

Conditions often have pre-defined values that are part of the rules themselves.

Numbers are represented in-text, both plain integers and fractional values: 1234 or 999.0001.

Text-based values, such as the order side or type, can be represented within single-quotes: order.type = 'Limit'.

Vetting also provides a short-hand for text values with the is and is not operators: order.type is Limit.

Values that can either be true or false are represented simply as true or false: security.isindex = true


Properties are values provided by the order management and market data systems to compare against.

Each property has a name, such as balance.currency, details.side.

Properties are case-sensitive. For example: balance.Currency is an invalid property.

Mathematical Operations

The Vetting Engine allows you to perform calculations with both pre-defined values and properties, such as 3 / 5, order.price * order.quantity * 10.

The Vetting Engine supports the following operators:

Operator Description Example
+ Addition order.value + balance.amount
- Subtraction balance.amount - order.value
* Multiplication details.quantity * details.limit
/ Division order.value / details.quantity
% Modulus (Remainder) details.quantity % 100
^ Exponent details.quantity * 10 ^ 4
- Negate -order.value

Operators obey the normal order of precedence: Parenthesis, Exponent, Division/Modulus, Multiplication, Addition, then Subtraction/Negation.