Message Builder

The message builder is available both as a standalone tool and within the context of manual FIX sessions. It's used to create valid FIX messages that conform to the FIX spec they're targeted to. Its behavior differs slightly depending on whether the standalone version is used, and these differences are explained below.

As a standalone tool, the message builder is accessible under the Tools tab of a FIX spec by selecting Message Builder on the left-hand sidebar. It can be used for various purposes, including creating FIX messages for documentation, producing examples for clients, or generating messages to be consumed by other tools.

In an active manual FIX session, select the Send tab to view the message builder, where you can configure and send FIX messages for that session.

Selecting Fields

By default, a message's required fields are added automatically. To add additional fields to the top-level message body, click the Add fields button at the bottom of the message builder. A dialog will appear containing the fields and components to be added.

To remove a field, click the delete () button next to the field's name. You cannot remove a field if it's required by the spec.

To add fields to a component, click the Add fields button that appears in the Value column alongside the component's name.

Components and Repeating Groups

Components and groups are displayed in alternating blue and yellow, with indentation at each stage to indicate their hierarchy. They can be collapsed () or expanded () by clicking the name of the group or component, which is followed by a chevron.

Selecting Repeating Group Fields

For repeating groups, the value of the NumInGroup field, which specifies the number of group elements, is derived automatically. To add elements to a repeating group, click the plus () button. To remove an element, use the delete () button in the element header (e.g. Element 1).

To add fields to a specific group element, click the Add fields to element button in the Value column.

Auto Fields

Several fields support the special value AUTO, which produces unique behaviour depending on the tag. If AUTO is used for a supported field, the value will appear in grey and italics.