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PayOps Kit
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Free · keyless · REST, OpenAPI and MCP

Payment-ops utilities for people and AI agents.

Check routing numbers, IBANs and BICs, do banking-day math, work out ACH deadlines, look up payment codes and verify finance identifiers. Each tool runs in your browser, and the same code answers a REST API and an MCP server — no key, no account, nothing stored.

Browse the toolsConnect an agent
curl -s 'https://payopskit.com/api/v1/routing-number/021000021'

The response is an excerpt of what validate_routing_number returns for the same input.

Private by design.

What you check stays yours.

Computed on your device

Tool pages run every check in this page’s JavaScript. Nothing you type is sent anywhere.

A stateless API

The REST API and MCP server answer each request in memory. Inputs are never stored or logged. No key, no account.

Open about usage

Our public analytics show exactly what we count — anonymous totals, never what you checked.

0 bytes of what you type leave the page; its only requests are anonymous counters (a page view, a tool used). Check it yourself in your browser’s developer tools (Network tab).

The tools

Eight checks, one implementation.

Every tool is a page with instant results (most take a pasted list too), a REST endpoint and an MCP tool, all running the same TypeScript.

  • US · ABA routing numbers

    Routing Number Validator

    Check the 3-7-1 checksum, work out a missing check digit and read the Federal Reserve district. Paste a list to check many at once.

    021000021

    Check a routing number

  • International · IBAN

    IBAN Validator

    Validate mod-97 check digits and the BBAN structure for every country in the IBAN registry, extract bank and branch codes, compute check digits.

    DE89 3704 0044 0532 0130 00

    Validate an IBAN

  • International · BIC / SWIFT

    BIC / SWIFT Parser

    Split a BIC into institution, country, location and branch; spot test and passive BICs; convert between BIC8 and BIC11.

    DEUTDEFF500

    Parse a BIC

  • Calendars · Fed · TARGET2 · UK

    Business Day Calculator

    Is it a banking day? Add or count business days, find the next one, list a year’s holidays or download them as a calendar file.

    us-fed · target2 · uk-ew

    Do business-day math

  • US · ACH timing

    ACH Date Calculator

    When an entry settles (Same Day windows or next day), the return deadline for a reason code, NOC timing and the reversal window.

    R01 · R10 · C01

    Work out ACH dates

  • Reference · Codes

    Payment Code Lookup

    Search ACH return and NOC codes, SEC codes, ISO 20022 status reasons and ISO 4217 currencies with their minor units.

    R01 · AC04 · USD

    Look up a code

  • Securities & entities

    Identifier Check Digits

    Verify the check digits of an LEI, ISIN, CUSIP or SEDOL, or run a Luhn check. The type is detected for you.

    LEI · ISIN · CUSIP · SEDOL

    Check an identifier

  • Checks · Amount in words

    Check Amount in Words

    Write a dollar amount out the way a check needs it, and cross-check written words against the figure.

    $1,234.56

    Write an amount in words

Quickstart

Call it from a script, or hand it to an agent.

JSON over HTTPS with no key, about 120 requests a minute per visitor. The MCP server speaks Streamable HTTP and is stateless, so any MCP client can connect with just the URL.

REST

curl -s 'https://payopskit.com/api/v1/routing-number/021000021'

GET with a path or query for one value, POST {"values": […]} for a batch. Errors share one shape: {"error": {"code", "message"}}.

MCP

claude mcp add --transport http payops-kit https://payopskit.com/mcp
  • Claude Code: Run in a terminal
  • Claude Desktop and claude.ai: Settings → Connectors → Add custom connector: name "PayOps Kit", URL
  • Cursor: ~/.cursor/mcp.json (or .cursor/mcp.json in a project)
  • VS Code: .vscode/mcp.json

12 MCP tools, all read-only

  • validate_routing_number
  • lookup_bank_by_routing_number
  • validate_iban
  • compute_iban_check_digits
  • parse_bic
  • business_day_math
  • list_bank_holidays
  • ach_settlement_date
  • ach_return_deadline
  • lookup_payment_code
  • validate_identifier
  • amount_to_words

API and MCP docsOpenAPI 3.1 (openapi.json)llms.txt

Why it exists

The everyday checks, in one place.

Treasury, AP and AR teams check the same things every week: is this routing number real, is that IBAN well formed, when does a Same Day file settle, how long do we have to return an unauthorized debit, what does AC04 mean. The answers are scattered across single-purpose sites, and most APIs for them want a key and a contract.

PayOps Kit puts routing numbers, IBAN and BIC, banking calendars, ACH deadlines, payment codes and finance identifiers behind one free, keyless service — a fast page for people, and REST, OpenAPI, MCP and llms.txt for the scripts and AI agents acting on their behalf. It is a sister site of NACHA Navigator and runs on donations.