Paypay MCP

Name: Paypay MCP
Author: mrslbt

by mrslbtversion 0.2.1i★ –iRuns on your computer

Registry nameio.github.mrslbt/paypay-mcp

Install

Overview

Description from the maker (original English)

PayPay QR payments for AI agents: QR codes, status, refunds, cancels. Bilingual JP/EN.

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Other

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "paypay": {
      "command": "npx",
      "args": [
        "-y",
        "paypay-mcp"
      ]
    }
  }
}

Run this in your terminal

claude mcp add paypay -- npx -y paypay-mcp

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "paypay": {
      "command": "npx",
      "args": [
        "-y",
        "paypay-mcp"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "paypay": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "paypay-mcp"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

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 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account mrslbt, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Otheri

More stars than 0% of the other 18436 servers in this category
Published to the registry more recently than 21% of the other 18436 servers in this category
Basic checks equal to or better than 100% of the other 18436 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is Paypay MCP safe?

It passed 1 of 1 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.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.2.1) reached the registry 3 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: Spec Driven Development, Remote Desktop Commander, Tethered Trust

Alternatives

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README from the maker

Open the README

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.

paypay-mcp

Model Context Protocol server for the PayPay Open Payment API.

Works with Claude Desktop, Claude Code, Cursor, Windsurf, Zed, ChatGPT Apps SDK, and any other MCP-compatible client. Tool descriptions are provided in English and Japanese.

Status

v0.2.x — production-capable, not yet battle-tested at scale.

The server runs cleanly against PayPay's production Open Payment API once PAYPAY_ENV=production is set with approved merchant credentials. It has not yet processed meaningful real-world volume. If you are routing real payments through it, pin the version and review the source first.

Tools

Tool	Description
`create_qr_code`	Create a dynamic PayPay QR code. Returns the payment URL, deeplink, and a rendered PNG.
`get_payment_details`	Fetch the current status of a payment.
`wait_for_payment`	Poll until a payment reaches a terminal state.
`delete_qr_code`	Invalidate a QR code before payment.
`refund_payment`	Full or partial refund. Disabled unless `PAYPAY_ENABLE_REFUNDS=true`.
`cancel_payment`	Cancel a payment when its state is unclear (timeout or error). Disabled unless `PAYPAY_ENABLE_CANCELS=true`.

Prompts

accept_single_payment, refund_last_payment, debug_stuck_payment.

Resources

URI	Description
`paypay://docs/opa-reference`	Endpoint map, auth scheme, and status vocabulary for the PayPay OPA API.
`paypay://docs/payment-states`	Payment lifecycle and the cancel-vs-refund decision rule.
`paypay://config/current`	Non-secret view of the active config (env, merchantId, baseUrl, transport).

Install

One-click:

Or via npm:

npm install -g paypay-mcp

Configuration

Credentials come from the PayPay Developer Dashboard.

Variable	Required	Description
`PAYPAY_API_KEY`	yes	OPA API Key ID
`PAYPAY_API_SECRET`	yes	OPA API Key Secret
`PAYPAY_MERCHANT_ID`	yes	Merchant ID
`PAYPAY_ENV`	no	`sandbox` (default) or `production`
`PAYPAY_ENABLE_REFUNDS`	no	Set to `true` to expose `refund_payment`. Disabled by default.
`PAYPAY_ENABLE_CANCELS`	no	Set to `true` to expose `cancel_payment`. Disabled by default.
`MCP_TRANSPORT`	no	`stdio` (default) or `http`
`MCP_HTTP_PORT`	no	Port when `MCP_TRANSPORT=http`. Default `3000`.
`MCP_HTTP_HOST`	no	Bind address. Default `127.0.0.1`. Public binds require `MCP_AUTH_TOKEN`.
`MCP_AUTH_TOKEN`	no	Bearer token required on inbound HTTP requests when set. Mandatory for non-loopback binds.
`MCP_HTTP_ALLOWED_ORIGINS`	no	Comma-separated CORS allowlist. Default: none.

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

"mcpServers": { "paypay": { "command": "npx", "args": ["-y", "paypay-mcp"], "env": { "PAYPAY_API_KEY": "a_...", "PAYPAY_API_SECRET": "...", "PAYPAY_MERCHANT_ID": "...", "PAYPAY_ENV": "sandbox" } } } }

Claude Code

claude mcp add paypay -e PAYPAY_API_KEY=... -e PAYPAY_API_SECRET=... -e PAYPAY_MERCHANT_ID=... -- npx -y paypay-mcp

Cursor

Add to ~/.cursor/mcp.json with the same shape as Claude Desktop.

Remote hosting

Run in HTTP mode. Public binds require MCP_AUTH_TOKEN; the server refuses to start otherwise.

MCP_TRANSPORT=http \

MCP_HTTP_HOST=0.0.0.0 \ MCP_AUTH_TOKEN="$(openssl rand -hex 32)" \ MCP_HTTP_ALLOWED_ORIGINS="https://claude.ai,https://your-app.example.com" \ PAYPAY_ENV=sandbox \ PAYPAY_API_KEY=... PAYPAY_API_SECRET=... PAYPAY_MERCHANT_ID=... \ npx paypay-mcp

Endpoint: POST http(s):// :3000/mcp (Streamable HTTP transport). Clients send Authorization: Bearer . CORS is closed by default.

For local testing the auth token can be omitted; the server binds to 127.0.0.1 and only accepts loopback connections.

Environments

Sandbox is the default. Production requires PayPay merchant onboarding (business verification and a contract) and must be enabled by explicitly setting PAYPAY_ENV=production.

Constraints

Amounts are integer JPY.
A payment can be canceled until 00:14:59 JST the day after the payment attempt. After that, use a refund.
A single order can receive multiple partial refunds, each with a unique merchantRefundId, up to the merchant-configured cap.
TLS 1.2+ required (Node 20+).

Development

git clone https://github.com/mrslbt/paypay-mcp.git

cd paypay-mcp npm install cp .env.example .env npm run dev npm test npm run smoke npm run build

Roadmap

v0.2: PreAuth + Capture, ContinuousPayments, DirectDebit, AccountLink QR, webhook signature verification, reconciliation tools.

v0.3: Native Payment (App Invoke + user JWT auth), Visa-partnership endpoints, OpenTelemetry tracing.

Safety

This server can move real money through the PayPay OPA API. Key safeguards:

Refund and cancel tools are disabled by default. refund_payment and cancel_payment are only registered when PAYPAY_ENABLE_REFUNDS=true or PAYPAY_ENABLE_CANCELS=true. Only enable them in trusted agent contexts where tool inputs cannot be influenced by untrusted content.
Sandbox is the default. Production requires an explicit PAYPAY_ENV=production, plus completed PayPay merchant onboarding. Always test against sandbox first.
Unique merchantPaymentId and merchantRefundId per call. PayPay deduplicates by these IDs, so reusing one will either fail or target an older payment. Generate a fresh ID for each new payment or refund.
Tools carry MCP safety annotations. Read-only tools (get_payment_details, wait_for_payment) are flagged readOnlyHint; money-moving and destructive tools (refund_payment, cancel_payment, delete_qr_code) are flagged destructiveHint so compatible clients can warn you before the call. These are advisory hints — the real guard is the gating above.

Even with these gates on, review any money-moving request before approving the tool call. Treat tool inputs derived from model output as untrusted.

Disclaimer

This is an unofficial, community-built MCP server. Not affiliated with, endorsed by, or sponsored by PayPay Corporation. PayPay is a registered trademark of its respective owners. Use at your own risk. The author accepts no liability for funds lost through misuse, prompt injection, or bugs.

License

MIT

Paypay MCP

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Otheri

Common questions

Alternatives

Spec Driven Development

Remote Desktop Commander

Tethered Trust

README from the maker

paypay-mcp

Status

Tools

Prompts

Resources

Install

Configuration

Claude Desktop

Claude Code

Cursor

Remote hosting

Environments

Constraints

Development

Roadmap

Safety

Disclaimer

License