Billing Line Items

Last updated: 5 Oct 2026

The Canvas SDK allows you to create, update, and remove Billing Line Items from the footer of a note.

Adding a Billing Line Item #

To add a billing line item to a note, build an AddBillingLineItem and return its apply() from your handler.

Methods #

apply() → Effect #

Adds the billing line item to the note’s footer.

• note_id and cpt are required.
• units defaults to 1.

Attributes #

Attribute	Type	Description	Required
note_id	String	The id of the Note where the line item should be associated.	Yes
cpt	String	The billing code to use for the line item.	Yes
units	Integer	The number of units to bill for the code. Defaults to 1 if not provided.	No
assessment_ids	list[String]	List of Assessment ids from the note that are relevant to the code, also referred to as “diagnosis pointers”.	No
modifiers	list[Coding]	The modifiers to create with the billing code.	No

Example #

from canvas_sdk.effects import Effect
from canvas_sdk.events import EventType
from canvas_sdk.handlers import BaseHandler
from canvas_sdk.v1.data import Command, Assessment
from canvas_sdk.effects.billing_line_item import AddBillingLineItem


class MyHandler(BaseHandler):
    RESPONDS_TO = [
        EventType.Name(EventType.PERFORM_COMMAND__POST_ORIGINATE)
    ]

    def compute(self) -> list[Effect]:
        command_id = self.target
        command = Command.objects.get(id=command_id)
        note = command.note

        assessments = [
            str(i)
            for i in Assessment.objects.filter(note_id=note.dbid).values_list(
                "id", flat=True
            )
        ]

        b = AddBillingLineItem(
            note_id=str(note.id),
            cpt="99213",
            units=1,
            assessment_ids=assessments,
            modifiers=[
                {"code": "25", "system": "http://www.ama-assn.org/go/cpt"},
                {"code": "59", "system": "http://www.ama-assn.org/go/cpt"},
            ],
        )
        return [b.apply()]

You don’t set the line item’s description in your plugin. When the line item is created, Canvas matches the cpt to a ChargeDescriptionMaster charge and populates the description from that charge’s short_name, truncated to 255 characters. If no charge matches the cpt, the description is left empty.

Adding billing codes from an external system #

To populate diagnosis and CPT codes in a note footer from an external billing system, expose a SimpleAPI endpoint that the system can call. The endpoint receives the note, CPT code, units, and ICD-10 codes, matches the ICD-10 codes to the note’s assessments, and returns an AddBillingLineItem effect whose assessment_ids act as the line item’s diagnosis pointers. This example authenticates with APIKeyAuthMixin, which checks requests against a plugin secret named simpleapi-api-key:

from http import HTTPStatus

from canvas_sdk.effects import Effect
from canvas_sdk.effects.billing_line_item import AddBillingLineItem
from canvas_sdk.effects.simple_api import JSONResponse, Response
from canvas_sdk.handlers.simple_api import APIKeyAuthMixin, SimpleAPIRoute
from canvas_sdk.v1.data.assessment import Assessment


class BillingAPI(APIKeyAuthMixin, SimpleAPIRoute):
    PATH = "/billing/add-line-item"

    def post(self) -> list[Response | Effect]:
        # {"note_id": "...", "cpt_code": "99213", "units": 1, "icd10_codes": ["E119", "I10"]}
        body = self.request.json()
        note_id = body["note_id"]
        icd10_codes = {code.upper().replace(".", "") for code in body.get("icd10_codes", [])}

        # Use each of the note's assessments whose condition carries a requested ICD-10 code
        assessment_ids = [
            str(assessment.id)
            for assessment in Assessment.objects.filter(note__id=note_id).select_related("condition")
            if assessment.condition
            and any(
                coding.system == "ICD-10" and coding.code.upper().replace(".", "") in icd10_codes
                for coding in assessment.condition.codings.all()
            )
        ]

        effect = AddBillingLineItem(
            note_id=note_id,
            cpt=body["cpt_code"],
            units=body.get("units", 1),
            assessment_ids=assessment_ids,
        )

        return [
            effect.apply(),
            JSONResponse(
                {"message": "Billing line item sent to Canvas", "assessment_ids": assessment_ids},
                status_code=HTTPStatus.CREATED,
            ),
        ]

The cpt-billing-api example plugin builds on this with request validation, a check that the CPT code is active in the charge description master, and a response listing which ICD-10 codes matched.

Updating a Billing Line Item #

To update a billing line item, build an UpdateBillingLineItem and return its apply() from your handler.

Methods #

apply() → Effect #

Updates the billing line item.

• billing_line_item_id is required.
• Only the attributes you set on the effect are changed. Attributes you leave unset keep their current values.

Attributes #

Attribute	Type	Description	Required
billing_line_item_id	String	The id of the BillingLineItem to update.	Yes
cpt	String	The billing code to use for the line item.	No
units	Integer	The number of units to bill for the code.	No
assessment_ids	list[String]	List of Assessment ids from the note that are relevant to the code, also referred to as “diagnosis pointers”.	No
modifiers	list[Coding]	The modifiers to create with the billing code.	No

Example #

from canvas_sdk.effects import Effect
from canvas_sdk.events import EventType
from canvas_sdk.handlers import BaseHandler
from canvas_sdk.v1.data import Assessment, Command, BillingLineItem
from canvas_sdk.effects.billing_line_item import UpdateBillingLineItem


class MyHandler(BaseHandler):
    RESPONDS_TO = [
        EventType.Name(EventType.PERFORM_COMMAND__POST_COMMIT)
    ]

    def compute(self) -> list[Effect]:
        command_id = self.target
        command = Command.objects.get(id=command_id)
        note = command.note

        cpt = command.data["perform"]["value"]

        b_ids = BillingLineItem.objects.filter(cpt="99213", note=note).values_list(
            "id", flat=True
        )
        assessment = Assessment.objects.filter(note_id=note.dbid).first()
        updates = [
            UpdateBillingLineItem(
                billing_line_item_id=str(b_id),
                cpt=cpt,
                units=1,
                assessment_ids=[str(assessment.id)],
                modifiers=[{"code": "47", "system": "http://www.ama-assn.org/go/cpt"}],
            )
            for b_id in b_ids
        ]
        return [update.apply() for update in updates]

Removing a Billing Line Item #

To remove a billing line item, build a RemoveBillingLineItem and return its apply() from your handler.

Methods #

apply() → Effect #

Removes the billing line item from the note’s footer.

• billing_line_item_id is required.

Attributes #

Attribute	Type	Description	Required
billing_line_item_id	String	The id of the BillingLineItem to remove.	Yes

Example #

from canvas_sdk.effects import Effect
from canvas_sdk.events import EventType
from canvas_sdk.handlers import BaseHandler
from canvas_sdk.v1.data import Command, BillingLineItem
from canvas_sdk.effects.billing_line_item import RemoveBillingLineItem


class MyHandler(BaseHandler):
    RESPONDS_TO = [
        EventType.Name(EventType.PERFORM_COMMAND__POST_ENTER_IN_ERROR)
    ]

    def compute(self) -> list[Effect]:
        command_id = self.target
        command = Command.objects.get(id=command_id)

        cpt = command.data["perform"]["value"]
        note_id = command.note.dbid
        b_ids = BillingLineItem.objects.filter(cpt=cpt, note_id=note_id).values_list(
            "id", flat=True
        )
        return [
            RemoveBillingLineItem(billing_line_item_id=str(b_id)).apply()
            for b_id in b_ids
        ]

For more information about the BillingLineItem data class, check out this page.