`invoices.plans.create`

Create a payment plan that splits a project into 2 to 12 installment invoices on set dates, by percentages or exact pre-tax amounts that add up to the subtotal. Each installment is prepared ahead of time and needs approval before it is sent.

POST/api/v1/accounting/invoices.plans.create

Permissions

accounting:readaccounting:write

Who can call it

admin, finance

Retries

Idempotency key required

MCP

accounting_invoices_plans_create

Fields

partyIdstring (ID)Required
The ID of a customer or vendor account, from parties.list.
namestringRequired
A display name.
1–200 characters
templateobjectRequired
No other fields
installmentsarray of objectsRequired
2–12 items
reviewLeadDaysinteger
0 to 60
autoSendAfterApprovalboolean
Default true
idempotencyKeystringRequired
Any unique text you generate once per intended change, so a retried request only happens once. Send it as the Idempotency-Key header instead if you prefer; if you send both they must match.
8–200 characters

curl https://app.getoatmilk.com/api/v1/accounting/invoices.plans.create \
  -H "Authorization: Bearer $OATMILK_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
  "partyId": "7f0f6c1e-1c1f-4b5e-9c8d-2f5e8e3c1a10",
  "name": "Synthetic Ventures Inc.",
  "template": {
    "lines": [
      {
        "description": "Synthetic example from the docs",
        "unitAmountMinor": "1250"
      }
    ]
  },
  "installments": [
    {
      "date": "2026-09-30"
    },
    {
      "date": "2026-09-30"
    }
  ]
}'

const response = await fetch("https://app.getoatmilk.com/api/v1/accounting/invoices.plans.create", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.OATMILK_API_KEY}`,
    "Content-Type": "application/json",
    "Idempotency-Key": crypto.randomUUID(),
  },
  body: JSON.stringify({
    "partyId": "7f0f6c1e-1c1f-4b5e-9c8d-2f5e8e3c1a10",
    "name": "Synthetic Ventures Inc.",
    "template": {
      "lines": [
        {
          "description": "Synthetic example from the docs",
          "unitAmountMinor": "1250"
        }
      ]
    },
    "installments": [
      {
        "date": "2026-09-30"
      },
      {
        "date": "2026-09-30"
      }
    ]
  }),
});
const { data, error } = await response.json();
if (!response.ok) throw new Error(`${error.code}: ${error.message}`);
console.log(data);

import os
import uuid

import requests

response = requests.post(
    "https://app.getoatmilk.com/api/v1/accounting/invoices.plans.create",
    headers={
        "Authorization": f"Bearer {os.environ['OATMILK_API_KEY']}",
        "Idempotency-Key": str(uuid.uuid4()),
    },
    json={
        "partyId": "7f0f6c1e-1c1f-4b5e-9c8d-2f5e8e3c1a10",
        "name": "Synthetic Ventures Inc.",
        "template": {
            "lines": [
                {
                    "description": "Synthetic example from the docs",
                    "unitAmountMinor": "1250",
                },
            ],
        },
        "installments": [
            {
                "date": "2026-09-30",
            },
            {
                "date": "2026-09-30",
            },
        ],
    },
    timeout=30,
)
payload = response.json()
if not response.ok:
    raise RuntimeError(f"{payload['error']['code']}: {payload['error']['message']}")
print(payload["data"])

Response

{
  "data": { … }
}

Try it

Checks your input with this action’s real schema and answers like the API, with synthetic data. No key needed, and nothing changes.

Input

POST/api/v1/accounting/invoices.plans.create

curl https://app.getoatmilk.com/api/v1/accounting/invoices.plans.create \
  -H "Authorization: Bearer $OATMILK_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
  "partyId": "7f0f6c1e-1c1f-4b5e-9c8d-2f5e8e3c1a10",
  "name": "Synthetic Ventures Inc.",
  "template": {
    "lines": [
      {
        "description": "Synthetic example from the docs",
        "unitAmountMinor": "1250"
      }
    ]
  },
  "installments": [
    {
      "date": "2026-09-30"
    },
    {
      "date": "2026-09-30"
    }
  ]
}'

const response = await fetch("https://app.getoatmilk.com/api/v1/accounting/invoices.plans.create", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.OATMILK_API_KEY}`,
    "Content-Type": "application/json",
    "Idempotency-Key": crypto.randomUUID(),
  },
  body: JSON.stringify({
    "partyId": "7f0f6c1e-1c1f-4b5e-9c8d-2f5e8e3c1a10",
    "name": "Synthetic Ventures Inc.",
    "template": {
      "lines": [
        {
          "description": "Synthetic example from the docs",
          "unitAmountMinor": "1250"
        }
      ]
    },
    "installments": [
      {
        "date": "2026-09-30"
      },
      {
        "date": "2026-09-30"
      }
    ]
  }),
});
const { data, error } = await response.json();
if (!response.ok) throw new Error(`${error.code}: ${error.message}`);
console.log(data);

import os
import uuid

import requests

response = requests.post(
    "https://app.getoatmilk.com/api/v1/accounting/invoices.plans.create",
    headers={
        "Authorization": f"Bearer {os.environ['OATMILK_API_KEY']}",
        "Idempotency-Key": str(uuid.uuid4()),
    },
    json={
        "partyId": "7f0f6c1e-1c1f-4b5e-9c8d-2f5e8e3c1a10",
        "name": "Synthetic Ventures Inc.",
        "template": {
            "lines": [
                {
                    "description": "Synthetic example from the docs",
                    "unitAmountMinor": "1250",
                },
            ],
        },
        "installments": [
            {
                "date": "2026-09-30",
            },
            {
                "date": "2026-09-30",
            },
        ],
    },
    timeout=30,
)
payload = response.json()
if not response.ok:
    raise RuntimeError(f"{payload['error']['code']}: {payload['error']['message']}")
print(payload["data"])

Fields

Fields inside template

Fields inside installments

Example

Try it