Tutorials

Export a month of transactions

Page through entries and write a spreadsheet your accountant can open.

10 minutes · Beginner

This script reads every entry in a month, page by page, and writes a CSV with the merchant, date, amount, tax and status. It's a starting point for a month-end report, a data warehouse load or a spreadsheet for your accountant.

1. Read every page

entries.list returns up to 500 entries per page. Ask for the month with from and to, and stop when a page comes back short.

GET/api/v1/accounting/entries.list

curl -G https://app.getoatmilk.com/api/v1/accounting/entries.list \
  -H "Authorization: Bearer $OATMILK_API_KEY" \
  --data-urlencode 'from=2026-09-01' \
  --data-urlencode 'to=2026-09-30' \
  --data-urlencode 'limit=500' \
  --data-urlencode 'offset=0'

const response = await fetch("https://app.getoatmilk.com/api/v1/accounting/entries.list?from=2026-09-01&to=2026-09-30&limit=500&offset=0", {
  headers: {
    Authorization: `Bearer ${process.env.OATMILK_API_KEY}`,
  },
});
const { data, error } = await response.json();
if (!response.ok) throw new Error(`${error.code}: ${error.message}`);
console.log(data);

import os

import requests

response = requests.get(
    "https://app.getoatmilk.com/api/v1/accounting/entries.list",
    headers={
        "Authorization": f"Bearer {os.environ['OATMILK_API_KEY']}",
    },
    params={
        "from": "2026-09-01",
        "to": "2026-09-30",
        "limit": "500",
        "offset": "0",
    },
    timeout=30,
)
payload = response.json()
if not response.ok:
    raise RuntimeError(f"{payload['error']['code']}: {payload['error']['message']}")
print(payload["data"])

export.js

import { writeFile } from "node:fs/promises";

const entries = [];
for (let offset = 0; ; offset += 500) {
  const page = await callOatmilk("entries.list", { from: "2026-09-01", to: "2026-09-30", limit: 500, offset });
  entries.push(...page);
  if (page.length < 500) break;
}

2. Write the CSV

Amounts are cents written as strings, so divide by 100 only when you format them, and keep each currency in its own column.

export.js

const cell = value => `"${String(value ?? "").replaceAll('"', '""')}"`;
const money = minor => (Number(minor) / 100).toFixed(2);
const rows = entries.map(entry => [entry.date, entry.merchant, entry.type, entry.currency, money(entry.amount_minor), money(entry.tax_minor), entry.status]);
const csv = [["Date", "Merchant", "Type", "Currency", "Amount", "Tax", "Status"], ...rows].map(row => row.map(cell).join(",")).join("\n");
await writeFile("2026-09.csv", csv);

Or let Oatmilk build it

For an export with every original receipt attached, or one ready for tax, ask Oatmilk to build it with reports.export. It runs in the background and tells you where to download it when it's done.

POST/api/v1/accounting/reports.export

curl https://app.getoatmilk.com/api/v1/accounting/reports.export \
  -H "Authorization: Bearer $OATMILK_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: $(uuidgen)" \
  -d '{
  "format": "csv",
  "from": "2026-09-01",
  "to": "2026-09-30"
}'

const response = await fetch("https://app.getoatmilk.com/api/v1/accounting/reports.export", {
  method: "POST",
  headers: {
    Authorization: `Bearer ${process.env.OATMILK_API_KEY}`,
    "Content-Type": "application/json",
    "Idempotency-Key": crypto.randomUUID(),
  },
  body: JSON.stringify({
    "format": "csv",
    "from": "2026-09-01",
    "to": "2026-09-30"
  }),
});
const { data, error } = await response.json();
if (!response.ok) throw new Error(`${error.code}: ${error.message}`);
console.log(data);

import os
import uuid

import requests

response = requests.post(
    "https://app.getoatmilk.com/api/v1/accounting/reports.export",
    headers={
        "Authorization": f"Bearer {os.environ['OATMILK_API_KEY']}",
        "Idempotency-Key": str(uuid.uuid4()),
    },
    json={
        "format": "csv",
        "from": "2026-09-01",
        "to": "2026-09-30",
    },
    timeout=30,
)
payload = response.json()
if not response.ok:
    raise RuntimeError(f"{payload['error']['code']}: {payload['error']['message']}")
print(payload["data"])