Pull your 弥生会計 books into your own systems

What you can build on 弥生会計 Next

• Get the trial balance

  Build this

  Reads 残高試算表 (trial balance) under 集計 for the months you choose, as 累計 (cumulative) or 推移 (monthly trend), with or without tax.

  Takes

  From month, to month, cumulative or monthly, tax included or excluded, department (optional)

  Returns

  Statement, account, sub-account, debit, credit, balance

• List unposted statement lines

  Build this

  Reads the 未仕訳 (unposted) tab of a 明細ボックス (statement box): fetched lines that have no journal entry yet, with the account already set on each.

  Takes

  Statement box name (optional)

  Returns

  Statement box, date, description, amount, suggested account, set by AI or by rule

• Get journal entries for a period

  Build this

  Reads the entries in 仕訳日記帳 (journal) for a date range, with the accounts on each side, the amount and the description.

  Takes

  From date, to date, department (optional)

  Returns

  Date, debit account, debit sub-account, credit account, credit sub-account, amount, description, department

• Post checked statement lines as journals

  Build this

  On the 未仕訳 tab of a 明細ボックス, checks the lines you list and registers their journal entries with 一括登録 (bulk register).

  Takes

  Statement box name, the lines to post (date, description, amount)

  Returns

  Lines posted, lines not found, lines left on the 未仕訳 tab

Automate 弥生会計 Next with a workflow

A workflow runs your methods as one process, with nobody at the screen. A schedule or a call from your own system starts it, the steps run in order, and the result arrives in your inbox or in the systems you already use.

• Unposted statement lines, every weekday morning

  Build this

  Starts

  Every weekday at 8:00

  Step 1

  List the unposted lines on the 未仕訳 tab of every 明細ボックス.

  Step 2

  Stop when there are none.

  Step 3

  Email you the lines grouped by statement box, with date, description, amount and suggested account.

• Last month's trial balance, summarized for you

  Build this

  Starts

  Monthly, on the 10th at 9:00

  Step 1

  Get the 残高試算表 for the last two months, as 推移, tax excluded.

  Step 2

  Have an AI step list the accounts whose balance moved most against the month before.

  Step 3

  Email you the summary with the full trial balance underneath.

• New journal entries, posted to your ERP

  Build this

  Starts

  Every Monday at 7:00

  Step 1

  Get the 仕訳日記帳 entries dated in the last 14 days.

  Step 2

  Keep the entries that were not there on the last run.

  Step 3

  Post each one, with its accounts, amount, description and department, to your ERP webhook.

You can run a workflow by hand on every plan, Free included. Schedules and webhook triggers come with the paid plans, from $29 a month.

Once built, one call from your code

Once you have built a method, it is one POST to /v1/runs from your backend, or a tool an AI agent calls over MCP. This is what “Get the trial balance” would look like.

curl https://api.fous.com/v1/runs \
  -H "Authorization: Bearer $FOUS_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "method": "myaccount.yayoi-kk.co.jp/get_trial_balance",
    "input": {
      "from_month": "2026-04",
      "to_month": "2026-10",
      "mode": "cumulative",
      "tax": "excluded"
    }
  }'

{
  "status": "completed",
  "data": {
    "accounts": [
      {
        "statement": "balance_sheet",
        "account": "普通預金",
        "sub_account": "Northwind Bank",
        "debit": 18450000,
        "credit": 15210000,
        "balance": 6840000
      }
    ],
    "currency": "JPY",
    "count": 1
  }
}

An example with invented data, not a ready-made endpoint. The method exists in your organization once you build it, and its name, inputs and fields follow your request.

弥生会計 Next’s own options

Yayoi publishes terms for the 弥生Web API, which gets, registers and changes data in the Yayoi products it designates and includes a linkage server for AI clients over MCP. It is free for customers with a contract for a Yayoi product, though some features may depend on the plan. 弥生会計 Next also exports journals as CSV and the trial balance as PDF or CSV.

Read on November 12, 2026: 弥生Web API terms of use, Exporting journals and opening balances, 弥生会計 Next plans.

Signing in to 弥生会計 Next

弥生会計 Next signs you in with your 弥生ID (an email address) and password. 2段階認証 (two-step verification) is off by default; when it is on, a code is sent by email or SMS. With Fous you sign in once through Yayoi's own sign-in with your own account: the login is sealed with AES-256, an emailed code is handled, and an expired session is signed back in.

Worth knowing

Journals are posted from the 未仕訳 tab only

Statement lines can be registered as journals on the 未仕訳 tab, not on the すべて tab. The すべて tab shows each line as it was fetched, so changes you made appear only in the 仕訳日記帳.

The trial balance CSV is several files

Exporting the 残高試算表 as CSV writes one file per statement: 貸借対照表, 損益計算書 and 製造原価報告書. A method you build to read the screen can return them as one list.

Department names can repeat

弥生会計 Next lets two departments share a name, and the journal export then writes both under the same name. Rename them first if the receiving system groups by department.

Rule changes do not touch fetched lines

The account on each statement line is set by AI or by a 仕訳ルール when the line is fetched. Changing a 仕訳ルール later does not change lines already in the 明細ボックス.

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