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This documentation covers Review Board 4.0. You can see the latest Review Board documentation or all other versions.

Adding Review Request Fields

One of the most common uses for extensions is to add custom fields to review requests. These fields act like any other field on a review request. They can be edited, saved along with a draft, published, and their history can be shown in the “Review request changed” boxes. Their data can be accessed through the extra_data fields of Review Request Resource and Review Request Draft Resource.

Creating new review request fields involves a few steps:

Creating a Field Subclass

Each field is first defined in Python using a subclass of BaseReviewRequestField. There are several built-in types which provide more specific behavior:

  • BaseEditableField - A simple single-line text field.
  • BaseTextAreaField - A multi-line text field, with optional Markdown support.
  • BaseCommaEditableField - A single-line text field which allows selecting multiple comma-separated values.
  • BaseCheckboxField - A boolean-valued field which is displayed as a checkbox.
  • BaseDropdownField - A field which allows selecting one of several predefined options. This additionally requires defining the options attribute, which is a list of 2-tuples containing a value and label.
  • BaseDateField - A field which allows selecting a date.

At a minimum, your subclass will need to define two class attributes, field_id and label. Depending on the type, there may be additional attributes which can be overridden to manipulate the behavior.


from reviewboard.reviews.fields import (BaseCommaEditableField,

class MilestoneField(BaseEditableField):
    field_id = 'myvendor_milestone'
    label = 'Milestone'

class NotesField(BaseTextAreaField):
    field_id = 'myvendor_notes'
    label = 'Notes'

class TagsField(BaseCommaEditableField):
    field_id = 'myvendor_tags'
    label = 'Tags'

class SecurityRelatedField(BaseCheckboxField):
    field_id = 'myvendor_security_related'
    label = 'Security Related'

class PriorityField(BaseDropdownField):
    field_id = 'myvendor_priority'
    label = 'Priority'
    options = [
        ('low', 'Low'),
        ('medium', 'Medium'),
        ('high', 'High'),

class DueDateField(BaseCommaEditableField):
    field_id = 'myvendor_due'
    label = 'Due Date'

Creating a JavaScript FieldView Subclass

Each Python field type has an associated JavaScript view which handles user interaction and value serialization. If you subclass one of the builtin field types, you do not need to create an override for these, but doing so can allow you to implement more advanced UIs such as autocomplete or custom editor widgets.


Suppose we wanted a field which used Selectize as its editor. First, we’d define a JavaScript view that set up Selectize on the editor’s field:

window.MyExtension = {};

MyExtension.SelectizeFieldView =

     * Render the view.
    render() {


We can then reference the new JavaScript view using the reviewboard.reviews.fields.BaseReviewRequestField.js_view_class attribute.

from reviewboard.reviews.fields import BaseEditableField

class MilestoneField(BaseEditableField):
    field_id = 'myvendor_milestone'
    label = 'Milestone'
    js_view_class = 'MyExtension.SelectizeField'

Extension Hooks

Review Board provides two hooks to add your custom fields. ReviewRequestFieldsHook can be used to add fields to one of the builtin sections. ReviewRequestFieldSetsHook can add entirely new sections. The documentation for each of these hooks shows example usage.