io.github.mrslbt/paypay-mcp
PayPay QR payments for AI agents: QR codes, status, refunds, cancels. Bilingual JP/EN.
Open source Open in the app JSON README (API)
About
PayPay QR payments for AI agents: QR codes, status, refunds, cancels. Bilingual JP/EN.
Details
- Kind
- MCP servers
- Topic
- Finance & crypto
- Publisher
- mrslbt
- Origin
- official
- Category
- ferramentas
- Transport
- local
- Version
- 0.2.1
- Last push
- 2026-08-12T07:57:08Z
- Repository state
- ativo
- Language
- TypeScript
- License
- MIT
- Added
- 2026-08-29 04:00:51
- Updated
- 2026-08-29 04:00:51
- Origin id
io.github.mrslbt/paypay-mcp
README
# paypay-mcp
[](https://www.npmjs.com/package/paypay-mcp)
[](https://www.npmjs.com/package/paypay-mcp)
[](https://lobehub.com/mcp/mrslbt-paypay-mcp)
[](LICENSE)
Model Context Protocol server for the [PayPay Open Payment API](https://www.paypay.ne.jp/opa/doc/v1.0/).
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:
[](cursor://anysphere.cursor-deeplink/mcp/install?name=paypay&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsInBheXBheS1tY3AiXX0=)
[](https://insiders.vscode.dev/redirect/mcp/install?name=paypay&config=%7B%22command%22%3A%22npx%22%2C%22args%22%3A%5B%22-y%22%2C%22paypay-mcp%22%5D%7D)
Or via npm:
```bash
npm install -g paypay-mcp
```
## Configuration
Credentials come from the [PayPay Developer Dashboard](https://developer.paypay.ne.jp/).
| 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`:
```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
```bash
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.
```bash
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)://<host>:3000/mcp` (Streamable HTTP transport). Clients send `Authorization: Bearer <MCP_AUTH_TOKEN>`. 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
```bash
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](LICENSE)