SolidInvoice
Create and send invoices and quotes, manage clients, and track payments in SolidInvoice.
Japan payroll & social insurance. 日本の給与計算・社会保険。47都道府県の料率、源泉所得税、割増賃金、有給、標準報酬月額の改定、最低賃金。根拠の条文つき。
Pick the AI app you use, then copy the settings.
Passed 5/5 checks · What you ask goes through the maker’s server (japan-payroll-api.tsumugi.workers.dev) · ✓ Commands checked Nov 13, 2026
First: which AI do you use?
Pick your app and the steps appear below.
Works with Claude · about 2 min
No key, nothing to install · Set it up once on claude.ai or the desktop app, then use it in chat · free accounts can add 1 · on Team/Enterprise an Owner adds it
CustomizeConnectors
Copy each value into the field with the same name in Claude, then click Continue
日本の給与・社会保険・労働法https://japan-payroll-api.tsumugi.workers.dev/mcpClick Continue past the sign-in settings Claude detected · under Authentication choose what the maker says (Sign in now, Sign in when needed or No sign in), then click Add
+Connectors日本の給与・社会保険・労働法
Use 日本の給与・社会保険・労働法 and tell me what you can do for me, then show me one thing✓ If Claude says it is using 日本の給与・社会保険・労働法 or shows a 日本の給与・社会保険・労働法 tool in the answer, you are connected
Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version
Works with ChatGPT, depending on your plan
Full MCP: ChatGPT Business, Enterprise or Edu on the web · Pro: connects with read/fetch permissions, so tools that change data may not work · Plus: not confirmed in OpenAI’s docs; if you see an add-custom-MCP option on the Plugins page you can try these steps · web only
Plugins+Add custom MCP server
Enter a name, paste the address under Connection, tick the risk warning and click Create as a plugin
日本の給与・社会保険・労働法https://japan-payroll-api.tsumugi.workers.dev/mcpStart a new chat and pick 日本の給与・社会保険・労働法 from your plugins before typing
Use 日本の給与・社会保険・労働法 and tell me what you can do for me, then show me one thing✓ If ChatGPT says it is using 日本の給与・社会保険・労働法 or shows a 日本の給与・社会保険・労働法 tool in the answer, you are connected
Menu names checked against OpenAI’s help page on Nov 11, 2026 · your screen may differ slightly by app version
Works with Claude Code · about 2 min
No key, nothing to install
Mac: press Command+Space and type Terminal · Windows: open PowerShell
claude mcp add --transport http --scope user jp-payroll https://japan-payroll-api.tsumugi.workers.dev/mcpYou should see 日本の給与・社会保険・労働法 listed as connected
Use 日本の給与・社会保険・労働法 and tell me what you can do for me, then show me one thing✓ If Claude Code says it is using 日本の給与・社会保険・労働法 or shows a 日本の給与・社会保険・労働法 tool in the answer, you are connected
Menu names checked against Anthropic’s help page on Nov 11, 2026 · your screen may differ slightly by app version
Works with Cursor · about 2 min
No key, nothing to install
Use 日本の給与・社会保険・労働法 and tell me what you can do for me, then show me one thing✓ If Cursor says it is using 日本の給与・社会保険・労働法 or shows a 日本の給与・社会保険・労働法 tool in the answer, you are connected
Menu names checked against Cursor’s help page on Nov 11, 2026 · your screen may differ slightly by app version
Works with VS Code · about 2 min
No key, nothing to install
Use 日本の給与・社会保険・労働法 and tell me what you can do for me, then show me one thing✓ If VS Code says it is using 日本の給与・社会保険・労働法 or shows a 日本の給与・社会保険・労働法 tool in the answer, you are connected
Menu names checked against VS Code’s help page on Nov 11, 2026 · your screen may differ slightly by app version
Other apps that use MCP, such as Windsurf, Zed or Gemini CLI, each add servers differently. See how in the app list.
Address for apps that connect over the web
https://japan-payroll-api.tsumugi.workers.dev/mcpJSON settings are under “For developers” below
Claude Code
claude mcp add --transport http --scope user jp-payroll https://japan-payroll-api.tsumugi.workers.dev/mcpCursor (~/.cursor/mcp.json)
{
"mcpServers": {
"jp-payroll": {
"url": "https://japan-payroll-api.tsumugi.workers.dev/mcp"
}
}
}VS Code (mcp.json)
{
"servers": {
"jp-payroll": {
"type": "http",
"url": "https://japan-payroll-api.tsumugi.workers.dev/mcp"
}
}
}Claude Code
claude mcp add --scope user jp-payroll -- npx -y jp-payroll-mcpClaude Desktop (claude_desktop_config.json)
{
"mcpServers": {
"jp-payroll": {
"command": "npx",
"args": [
"-y",
"jp-payroll-mcp"
]
}
}
}Cursor (~/.cursor/mcp.json)
{
"mcpServers": {
"jp-payroll": {
"command": "npx",
"args": [
"-y",
"jp-payroll-mcp"
]
}
}
}VS Code (mcp.json)
{
"servers": {
"jp-payroll": {
"type": "stdio",
"command": "npx",
"args": [
"-y",
"jp-payroll-mcp"
]
}
}
}These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.
Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.
Connect over the internet in
ClaudeChatGPTGooseLM StudioMsty StudioCherry StudioCursorVS Code + GitHub CopilotVisual StudioWindsurf (Devin Desktop)ZedKiroClineContinueJetBrains AI AssistantClaude CodeCodex CLIGemini CLIOpenCodenodecodeWarpLibreChatOpen WebUIRaycast
Run on your computer in
ClaudeGooseLM StudioMsty StudioCherry StudioCursorVS Code + GitHub CopilotVisual StudioWindsurf (Devin Desktop)ZedKiroClineContinueJetBrains AI AssistantClaude CodeCodex CLIGemini CLIOpenCodenodecodeWarpLibreChatRaycast
Tool names and descriptions exactly as the server reported them on Nov 15, 2026. The maker wrote them, not us; we show them as plain text.
calculate_payslipFull monthly deduction breakdown for one employee: health insurance, long-term care, pension, child support, employment insurance, withholding income tax and net pay, with the employer share as well. Use this rather than computing it yourself. Premiums are charged on 標準報酬月額 — a 5
list_workers_compensation_ratesWorkers compensation (労災保険) rates by business type, and the employer premium on a given 賃金総額. The whole premium falls on the employer — nothing is deducted from the employee, unlike every other statutory premium. Rates run from 2.5/1000 to 88/1000 depending on the industry, a 35-
calculate_bonusPremiums and income tax on a 賞与. Both work differently from monthly pay and are routinely got wrong. Premiums are charged on 標準賞与額 (the bonus truncated to the thousand yen) under two caps that behave differently: health, long-term care and child support cap at 5,730,000 yen CUMUL
calculate_withholding_taxIncome tax to withhold from a payment, from the National Tax Agency tables. The taxable amount is pay AFTER social insurance has been deducted, not gross. Pick the table with `period`: "monthly" for 月額表, "daily" for 日額表. The daily table has a third column, 丙, which applies to wor
judge_monthly_revisionDecides whether a pay change forces the standard remuneration to be revised, and answers SEPARATELY for health insurance and pension — the tables differ, so a change routinely moves one and not the other. Above roughly 665,000 yen the pension table is exhausted, so a large raise
decide_regular_remunerationThe yearly redetermination of standard remuneration, effective each September through the following August. Months below the payment-basis-day threshold drop OUT of the average entirely — they are not counted as zero, which is the usual mistake. If no month qualifies, the previou
judge_leave_end_revisionA separate route with a lower bar than 随時改定, and the one people forget. ONE grade of movement is enough, and fixed pay need not have changed at all — which matters because returning to shorter hours usually cuts pay without changing any rate, so 随時改定 would not fire and the employ
calculate_payroll_batchRuns calculate_payslip for many employees in one call and returns the run totals: gross, employee deductions, net, and employer cost. Reach for this the moment more than two or three people are in play. A monthly payroll is not a sequence of unrelated questions — the employer sha
decide_regular_remuneration_batchRuns the annual 定時決定 for a whole payroll in one call, and reports which employees moved grade. 健康保険法第41条 puts every insured employee on the same schedule — the average of April, May and June pay, over the months with at least seventeen payment-basis days, applied from September t
judge_annual_averageFor work whose April-June happens to be its busiest or quietest quarter, where the ordinary calculation would fix a grade that is wrong for eleven months of the year. Available for 定時決定 (since April 2011) and 随時改定 (since October 2018). The 随時改定 figure is NOT a plain twelve-month
lookup_standard_remunerationMaps a monthly amount to its health grade (1-50) and pension grade (1-32), with the standard remuneration each resolves to and whether the pension grade was clamped. Use it to check a grade, not to compute premiums — calculate_payslip does that.
national_insuranceFor anyone outside employee cover: the self-employed, freelancers, people between jobs. Use this instead of calculate_payslip when the person is not an employee. Running a freelancer through the payslip returns a figure computed under a different scheme entirely, with nothing in
calculate_annual_costWhat one employee costs an employer over a year, bonuses included. Reach for this rather than multiplying a payslip by twelve, because the two do not agree once a bonus is paid. 健康保険法第45条 caps the standard bonus cumulatively across the year — 5,730,000 from 1 April to 31 March —
judge_annual_leaveWorks out how many days of paid leave someone has been granted, and whether the employer still owes the five days it must direct. 労働基準法第39条 grants ten working days once six months of service are complete and attendance reaches eighty per cent of all working days, then adds one, t
judge_worker_typeDecides whether someone is covered by health and pension insurance, and on which payment-basis day count their annual determination runs. Call this before decide_regular_remuneration or judge_monthly_revision whenever the person is anything other than plainly full-time. Those too
check_insurance_eligibilityThe single most expensive month-end mistake in Japanese payroll, and one an assistant will get wrong from memory. Coverage ends the day AFTER the last day worked, not on it. So an employee leaving on the LAST day of a month loses coverage on the 1st of the next month, and still o
check_leave_exemptionMaternity and childcare leave look alike and behave differently. Maternity leave has no day-count test and exempts bonus premiums unconditionally; childcare leave gained a 14-day rule in October 2022 and exempts bonus premiums only when the leave exceeds one month. Two results ca
get_age_milestonesReturns the exact date each threshold is crossed and which premium starts or stops: long-term care begins at 40 and ends at 65, pension ends at 70, health insurance ends at 75 (transfer to 後期高齢者医療). Compute this here rather than by subtracting years. Under 年齢計算ニ関スル法律 an age is re
calculate_year_end_adjustmentYear-end adjustment (年末調整) for 2026 from the National Tax Agency's 令和8年分 booklet: the printed 給与所得控除後の給与等の金額 table (1,103 rows), the income-adjustment deduction, social/life/earthquake insurance deductions, spouse, specified-relative (19-22 with income), dependant, disability, wi
estimate_resident_taxEstimate of next fiscal year's resident tax (住民税: 道府県民税 + 市町村民税 + 森林環境税) from the previous year's income and the municipality: employment income from the NTA table for that year, resident-tax deductions (basic 430,000, spouse 330,000, dependants 330,000/450,000/380,000, life insu
get_insurance_ratesHealth insurance, long-term care, pension and child-support rates for a prefecture, plus the bonus caps and the employer-only child-care contribution. Health rates differ by prefecture and change each March; pension is national. Add business_type for the employment insurance rate
get_minimum_wageHourly 地域別最低賃金 for a prefecture. Revisions take effect prefecture by prefecture from October, on different days, so a date matters — pass one when checking a past payroll rather than assuming the current rate applied. History runs back to FY2002.
business_daysCount business days in a range, shift a date by N business days, or check one date. Covers 1955-2027 including substitute holidays, 国民の休日 (a weekday that is a holiday only because it sits between two others) and one-off imperial events, so the awkward years are right and not only
validate_invoice_numbers_batchChecks the National Tax Agency check digit on many qualified-invoice registration numbers in one call. Be careful how you report the result. A passing check digit means the shape of the number is right and nothing more. 消費税法第57条の2 provides both for the Commissioner to revoke a re
validate_corporate_numberChecks the National Tax Agency check digit on a 13-digit 法人番号, or on a qualified invoice registration number (the same 13 digits prefixed with T). This proves the number is well formed. It does NOT prove the number is registered, and it does not identify the holder: sole propriet
consumption_taxThe consumption tax rate in force on a date, with the national and local parts, and the reduced 8% rate for food and newspapers. Pass amount to have the tax worked out. Japan changed the rate four times since 1989 (3% → 5% → 8% → 10%), and the reduced rate has existed only since
get_statute_textReturns the full text of a Japanese statutory provision, as published by e-Gov. The judgement tools name the statute or notice their answer rests on, but not its words. Use this to quote the provision itself — a citation the reader can check beats a citation they have to take on
calculate_overtime_payWorks out statutory premium pay under 労働基準法第37条 — overtime, night work and work on a statutory holiday. The rates do not simply add up, and getting this wrong under-pays wages. A night premium stacks on top: overtime at night is 1.25 + 0.25 = 1.5, holiday work at night is 1.35 +
commuting_allowance_exemptionWorks out how much of a commuting allowance escapes income tax, and states the amount that still counts as remuneration for social insurance. These are two different bases, and that asymmetry is the part people get wrong. Social insurance counts a commuting allowance in full — it
check_data_freshnessJapanese statutory figures change on fixed dates — insurance rates each March, employment insurance each April, minimum wage each October — and a stale table produces numbers that look plausible and are wrong. This reports what every dataset currently covers and when its next rev
We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 16, 2026
The registry name was verified with the GitHub account kishida-devil, which owns the repo
Code last changed 2 months ago
Uses MIT
No sign-in needed
Read 30 tool descriptions and found no hidden instructions to the AI
No entries on OSV.dev for jp-payroll-mcp@0.4.5
Checks only this package version, not every dependency · checked Nov 15, 2026
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Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.
It passed 5 of 5 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.
The registry does not list a required key, though some servers ask you to sign in on first use.
Either way works: install it on your computer or connect to the cloud version.
The GitHub repo last changed 2 months ago, and the latest version (0.4.5) reached the registry 2 months ago.
Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. It connects by URL, so apps that accept remote MCP servers work too, such as ChatGPT on the web (full MCP on Business and above; Pro read-only).
In the same category: SolidInvoice, Signal8, Journalit, Tapetide - Indian Stock Market MCP, Twelve Data
Same category, other makers, commands already checked. Official ones first, then by stars.
Reading a card:↓ Downloads per weeki★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi
Create and send invoices and quotes, manage clients, and track payments in SolidInvoice.
Trading journal in Obsidian. Ask Claude or ChatGPT about your trades; edits are previewed first.
48 tools for ~8,000 NSE & BSE stocks: quotes, screener, financials, filings, FII/DII, options
Real-time and historical market data: stocks, forex, crypto, ETFs, fundamentals and 60+ indicators.
Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.
日本の給与計算・社会保険・労務を、表を引くのではなく計算して返すAPIとMCPサーバーです。 47都道府県の保険料率、源泉所得税、標準報酬月額の決定と改定、休業中の保険料免除、 割増賃金、年次有給休暇、最低賃金、営業日計算、令和8年分の年末調整、住民税の見込み額まで。答えには根拠の条文または通知が付きます。
公表されている料額表・税額表と1セルずつ突き合わせ、変更のたびに 4,689件 の検証を実行します。
MCPサーバー — AIアシスタントに日本語で聞く。30ツール、無料、APIキー不要。 URL を貼るだけ(remote MCP)か、npx で入れるか:
claude mcp add --transport http jp-payroll https://japan-payroll-api.tsumugi.workers.dev/mcp
claude mcp add jp-payroll -- npx -y jp-payroll-mcp
Claude.ai のカスタムコネクタ、ChatGPT、Cursor には https://japan-payroll-api.tsumugi.workers.dev/mcp を貼ります。
HTTP API — ソフトウェアに組み込む。45エンドポイント、OpenAPI 3.0、一括処理:
curl "https://japan-payroll-api.tsumugi.workers.dev/v1/payroll?prefecture=Tokyo&monthly_salary=350000&birth_date=1986-04-01"
MCPサーバーはAPIの薄い層なので、どちらも同じ答えを返します。 人が聞くのか、プログラムが聞くのかの違いです。
自前で書くと、もっともらしく見えて間違っている数字が出ます。3月31日退職と3月30日退職では 1か月分の社会保険料が動きます(東京・40歳・月給30万円で労使合計95,130円)。4月1日生まれの人は 3月31日に40歳になるので介護保険料が1か月早く始まります。随時改定の「2等級以上」は健康保険法に 書いておらず、昭和36年保発第4号にあります。
以下は英語の詳細仕様です。
Japanese payroll, social insurance and labour law, computed rather than looked up — premiums for all 47 prefectures, withholding tax, standard remuneration decisions and revisions, leave exemptions, minimum wage — with the statute or ministerial notice each answer rests on.
Verified against the published tables cell by cell: 4,689 assertions on every change.
As an MCP server, for asking questions through an AI assistant. 30 tools, free, no key. Remote (paste a URL) or local (npx):
claude mcp add --transport http jp-payroll https://japan-payroll-api.tsumugi.workers.dev/mcp
claude mcp add jp-payroll -- npx -y jp-payroll-mcp
For Claude.ai custom connectors, ChatGPT and Cursor, the URL is https://japan-payroll-api.tsumugi.workers.dev/mcp.
As an HTTP API, for building it into software. 45 endpoints, OpenAPI 3.0, batch:
curl "https://japan-payroll-api.tsumugi.workers.dev/v1/payroll?prefecture=Tokyo&monthly_salary=350000&birth_date=1986-04-01"
The MCP server is a thin layer over the API, so both give the same answers. Which you want depends on whether a person or a program is asking.
mcp/ · Englishhttps://japan-payroll-api.tsumugi.workers.dev/openapi.jsonJapanese statutory MCP servers mostly *retrieve* — they hand you the text of a law and leave the reasoning to you. This one *computes*, and returns the provision it relied on. They fit together rather than compete:
| "What does the law say?" | "So what do I pay?" | |
|---|---|---|
labor-law-mcp | 45 labour and social insurance laws, MHLW and JAISH notices | — |
tax-law-mcp | 24 tax laws, 17 NTA circulars, tribunal decisions | — |
hourei-mcp-server | Any Japanese law, via e-Gov | — |
| jp-payroll-mcp | The 28 provisions it cites, in full | Premiums, withholding tax, grade revisions, exemptions |
If you already run one of those, add this alongside it. An assistant with both picks the right one per question.
Source in mcp/, with its own README (日本語) · English. Test it with npm run mcp:test — it drives a real stdio transport with the real MCP client, because a tool with a broken handler still lists perfectly and only fails when something calls it.
The MCP server is free and always will be. It is a distribution channel rather than a revenue one: npm pays nothing and MCP has no billing of its own. That is deliberate — the problem was never billing, which RapidAPI already handles, but discovery, and MCP is where the traffic for Japanese statutory data measurably is.
| Endpoint | Description |
|---|---|
GET / | API info and endpoint list |
| Payroll and insurance | |
GET /v1/prefectures | All 47 prefectures with JIS codes |
GET /v1/insurance-rates?prefecture=Tokyo | Health, long-term care, pension, child-support rates |
GET /v1/standard-remuneration?remuneration=350000 | Grade lookup for a monthly amount |
GET /v1/standard-remuneration/table | Full 50-grade table |
GET /v1/employment-insurance?business_type=general | Employment insurance rates |
GET /v1/payroll?prefecture=Tokyo&monthly_salary=350000&age=40 | Full deduction breakdown |
| Minimum wage | |
GET /v1/minimum-wage?prefecture=Tokyo&date=2020-01-01 | Rate in effect on a date |
GET /v1/minimum-wage/history?prefecture=Tokyo | Full history since FY2002 |
| Calendar | |
GET /v1/holidays?year=2026 | Public holidays (or from=/to= for a range) |
GET /v1/holidays/check?date=2026-01-01 | Holiday / weekend / business-day flags |
GET /v1/business-days?from=&to= | Count business days in a range |
GET /v1/business-days/shift?date=&days=1 | Move N business days forward or back |
| Tax | |
GET /v1/consumption-tax?date=&amount=&reduced= | Rate in force, optionally applied to an amount |
GET /v1/consumption-tax/history | Every rate change since 1989 |
| Identifiers | |
GET /v1/corporate-number/validate?number=8700110005901 | 法人番号 check digit (Peppol ICD 0188) |
GET /v1/corporate-number/check-digit?base=700110005901 | Check digit for a 12-digit base number |
GET /v1/invoice-number/validate?number=T8700110005901 | Qualified invoice registration number |
| Withholding tax | |
GET /v1/withholding-tax?taxable_amount=300000&dependants=2 | Monthly withholding income tax (月額表) |
GET /v1/withholding-tax/daily?taxable_amount=12000&column=hei | Daily table (日額表), including the 丙 column |
GET /v1/withholding-tax/computer?taxable_amount=400000 | Same, by the formula method (電算機計算の特例) |
| Bonuses | |
GET /v1/bonus-tax?bonus=500000&previous_month_pay=350000 | Withholding on a bonus (賞与の算出率表) |
GET /v1/bonus-insurance?prefecture=Tokyo&bonus=800000&age=40 | Social insurance on a bonus, with both caps |
| Standard remuneration decisions | |
GET /v1/standard-remuneration/regular?months=350000:30,352000:31,349000:30 | 定時決定 (算定基礎) from April–June |
GET /v1/standard-remuneration/revision?current_remuneration=&months=&fixed_pay_change= | Is a 随時改定 (月額変更) due? |
GET /v1/standard-remuneration/leave-end?kind=childcare¤t_remuneration=&months= | Revision on returning from leave |
POST /v1/standard-remuneration/annual-average | 年間平均による保険者算定, for seasonal work |
| Year-end adjustment | |
POST /v1/year-end-adjustment | 年末調整 (令和8年分): every box of the 源泉徴収簿 from ⑦ to ㉗, plus an "if filed" estimate for medical/donation/casualty deductions |
| Resident tax | |
POST /v1/resident-tax | 住民税の見込み額 from last year's income and the municipality: income and per-capita levies, adjustment credit, ふるさと納税, exemptions, every prefecture's surtax |
| Eligibility and leave | |
GET /v1/eligibility?month=2026-03&left_on=2026-03-30 | Is a premium due in a joining or leaving month? |
GET /v1/leave-exemption?kind=childcare&start=&end= | Which months a maternity or childcare leave exempts |
GET /v1/age-milestones?birth_date=1986-04-01 | When 40, 65, 70 and 75 are reached, and what changes |
| Batch | |
POST /v1/payroll/batch | Up to 500 payslips in one call, with run totals |
| Statutes | |
GET /v1/statute?ref=健康保険法第43条 | Full text of a provision this API cites |
GET /v1/statute/index | Every provision available, with its law |
include=statute_text | Add to any endpoint to attach the text of whatever it cited |
| Meta | |
GET /v1/enums | Every accepted enum value and error code |
GET /v1/data-freshness | What each dataset covers and when it changes next |
prefecture accepts an English name (Tokyo, case-insensitive), Japanese (東京 or 東京都), or a JIS code (13).
Running payroll for one employee is a single request:
curl "https://japan-payroll-api.tsumugi.workers.dev/v1/payroll?prefecture=Tokyo&monthly_salary=350000&age=40&dependants=2"
gross 350,000
social insurance -55,750
after social insurance 294,250 <- the base withholding tax is charged on withholding income tax -4,480
net pay 289,770
That middle line is the point. Income tax is charged on pay after social insurance, not on gross pay, and deriving it by hand is the mistake this endpoint exists to stop. The response also carries the grade that was resolved, every premium split into employee and employer shares, and which bracket produced the tax — so the arithmetic can be audited rather than trusted.
Resident tax (住民税) is assessed by the municipality and notified to the employer; no API can compute it. Pass resident_tax= and it will be subtracted from net pay.
Pass income_tax=false to get social insurance only.
GET /v1/enums lists every accepted value — business_type, column, calendar — and every error code, so they can be read at build time instead of discovered from a 400.code. invalid_request and missing_parameter mean fix the call; out_of_coverage means the input was valid but falls outside what is published, which needs a different branch. Do not match on the English prose — it will change.GET /v1/data-freshness tells you how current each dataset is.| Dataset | Coverage | Source |
|---|---|---|
| Social insurance rates | 47 prefectures, FY2026 (令和8年度), effective 2026-03 | 協会けんぽ 保険料額表 |
| Standard remuneration table | 50 health grades / 32 pension grades | same |
| Employment insurance | 3 business types, FY2026, effective 2026-04-01 | 厚生労働省 |
| Minimum wage | 47 prefectures × 24 years (FY2002–FY2025) | 厚生労働省 地域別最低賃金 |
| Public holidays | 1,067 days, 1955–2027 | 内閣府 国民の祝日について |
| Consumption tax | 4 rate periods since 1989, with reduced rate | 国税庁 No.6303 |
| Corporate number check digit | algorithm, no dataset | 国税庁 チェックデジットの計算 |
| Withholding tax (monthly) | 231 brackets + 9 high-income anchors, 令和8年分 | 国税庁 源泉徴収税額表 |
| Withholding tax (formula) | 4 statutory tables, 令和8年分以降 | 電算機計算の特例 |
All figures are extracted programmatically from the official spreadsheets — not transcribed by hand. See `scrip