Payments MCP Servers Compared (2026): Stripe, PayPal, Paddle, Square and Adyen

• Stripe: hosted at https://mcp.stripe.com with OAuth or an agent API key. Generic tools (stripe_api_read, stripe_api_write) reach products, prices, payment links, invoices, refunds and more, plus search_stripe_documentation. Refunds need human confirmation when the agent acts with your user credentials. US domestic cards: 2.9% + 30¢.
• PayPal: hosted (https://mcp.paypal.com, sandbox at https://mcp.sandbox.paypal.com) or local with npx @paypal/mcp. Named tools such as create_product, create_invoice, create_order and create_refund. US rates: PayPal Checkout 3.49% + $0.49; standard card payments 2.99% + $0.49; advanced card payments 2.89% + $0.29.
• Paddle: hosted, with separate sandbox (https://sandbox-mcp.paddle.com/mcp) and live (https://mcp.paddle.com/mcp) endpoints. Two main tools: search and execute. Paddle is the merchant of record and files sales tax for you. Fee: 5% + 50¢ per checkout transaction.
• Square (beta): hosted at https://mcp.squareup.com/mcp (production only) or local with npx square-mcp-server start (sandbox possible). DISALLOW_WRITES=true makes the local server read-only. US online cards: 3.3% + 30¢ or 2.9% + 30¢ depending on plan; 2.9% + 30¢ for Online API payments.
• Adyen: local only, npx -y @adyen/mcp with --env=TEST or --env=LIVE. Covers the Checkout and Management APIs. Visa and Mastercard: $0.13 + interchange + 0.60% (Adyen lists this as a global rate, not a US one).
• Fees are the standard published rates for US online card payments (Adyen's is its global rate), checked on each vendor's pricing page on 2026-10-23. They change, and volume discounts exist.

Stripe runs one hosted MCP server. Its docs describe only the hosted server. Interactive clients sign in with OAuth, and on the consent page you can grant access to live mode accounts or sandboxes with different permissions for each. Autonomous agents use an agent API key with only the permissions they need.

claude mcp add --transport http stripe https://mcp.stripe.com/

{
  "mcpServers": {
    "stripe": {
      "type": "http",
      "url": "https://mcp.stripe.com",
      "headers": {
        "Authorization": "Bearer ${AGENT_API_KEY}"
      }
    }
  }
}

• Main tools: stripe_api_search, stripe_api_details, stripe_api_read (any GET method), stripe_api_write (POST, PATCH, PUT and DELETE methods), get_stripe_account_info, stripe_analytics, search_stripe_documentation and stripe_implementation_planner.
• Through stripe_api_write the agent can create products, prices, payment links, invoices, subscriptions, coupons and refunds, among other supported methods.
• Test mode: work in a sandbox. Stripe's docs say to test a new key configuration in a sandbox before expiring the old key. Admins can turn MCP access on or off separately for live mode and sandboxes in the Dashboard.
• Safety: when an agent connects with your user credentials, Stripe requires human confirmation before certain stripe_api_write actions, such as refunds and outbound payments. You approve through a URL the agent gives you, and the request expires after 24 hours.
• Gotcha: by November 30, 2026, switch to an agent API key or OAuth. From December, Stripe MCP stops accepting full-access secret keys and restricted API keys without the Agent tag.
• Gotcha: Connect platforms can act for a connected account by sending the Stripe-Account header, but OAuth is not supported for that; use an agent API key.
• Stripe asks you to turn on your client's tool-approval setting and to watch for prompt injection when Stripe runs alongside other servers.

• Stripe MCP server: install for every agent

PayPal offers a remote server and a local npm package with the same tool catalog. The local server reads a PayPal access token and an environment setting, and it defaults to the sandbox. The remote server accepts your PayPal client credentials as a Bearer token.

{
  "mcpServers": {
    "paypal": {
      "command": "npx",
      "args": ["-y", "@paypal/mcp", "--tools=all"],
      "env": {
        "PAYPAL_ACCESS_TOKEN": "YOUR_PAYPAL_ACCESS_TOKEN",
        "PAYPAL_ENVIRONMENT": "SANDBOX"
      }
    }
  }
}

• Remote endpoints: https://mcp.paypal.com/http (streamable HTTP) or https://mcp.paypal.com/sse in production, and https://mcp.sandbox.paypal.com/http or /sse for the sandbox.
• Catalog and subscriptions: create_product, list_products, update_product, create_subscription_plan, create_subscription, cancel_subscription.
• Invoices: create_invoice, send_invoice, send_invoice_reminder, cancel_sent_invoice.
• Payments: create_order, get_order, pay_order, create_refund, get_refund. Disputes and reporting: list_disputes, accept_dispute_claim, list_transactions.
• Test mode: PAYPAL_ENVIRONMENT is SANDBOX or PRODUCTION and defaults to SANDBOX. Get sandbox credentials from the PayPal developer dashboard.
• Gotcha: there is no payment link tool and no docs search tool in the published list. --tools=all loads every tool, including create_refund and accept_dispute_claim, so keep tool approval on.
• Gotcha: if the remote connection fails, PayPal's docs suggest clearing cached auth files with rm -rf ~/.mcp-auth.

• PayPal MCP server: install for every agent

Paddle's MCP server became a hosted service in May 2026. Sandbox and live have separate URLs. Live connects with OAuth or a live API key. The sandbox does not support OAuth, so you pass a sandbox API key as a Bearer token.

claude mcp add --transport http paddle-live https://mcp.paddle.com/mcp

{
  "mcpServers": {
    "paddle-sandbox": {
      "type": "http",
      "url": "https://sandbox-mcp.paddle.com/mcp",
      "headers": {
        "Authorization": "Bearer pdl_sdbx_YOUR_KEY"
      }
    }
  }
}

• Main tools: search (finds Paddle API methods), execute (runs a JavaScript function that chains one or more Paddle API calls), report_missing_tool and show_metrics_chart.
• Through execute the agent reaches the Paddle API, such as products, prices, transactions, subscriptions and adjustments.
• Test mode: use the sandbox URL. Sandbox keys start with pdl_sdbx_ and only work there.
• Key scoping: a live OAuth connection starts with read access to what your Paddle role permits. Grant more under Paddle > Connectors > MCPs. Charts need metrics.read and reports need report.write.
• Gotcha: the server does not gate destructive operations. They carry a destructiveHint annotation and may return a warning field. Paddle recommends your client's ask permission mode so you approve each execute.
• Docs search lives in a separate server that needs no Paddle account or API key (you sign in with Google or GitHub the first time): claude mcp add --transport http paddle-docs https://paddlehq.mcp.kapa.ai
• The older local npm package still works but gets no new API operations, and Paddle plans to deprecate it.

• Paddle MCP server: install for every agent

• Square: the server is in beta. The remote server at https://mcp.squareup.com/mcp signs in with your Square account but only reaches production. For testing, run it locally against a Sandbox with ACCESS_TOKEN and SANDBOX set: npx square-mcp-server start. Set DISALLOW_WRITES=true for read-only. The GitHub README lists three tools: get_service_info, get_type_info and make_api_request. Square keeps an allowlist of MCP clients.
• Adyen: local only. Test with npx -y @adyen/mcp --env=TEST and live with --env=LIVE --livePrefix=YOUR_PREFIX_URL. The key comes from ADYEN_API_KEY. Limit tools with --tools=name1,name2. Adyen advises running only the tools you need and creating a new webservice user and API key for the agent.

• Test mode first: Stripe sandbox, PayPal SANDBOX, Paddle sandbox URL, Square local Sandbox, Adyen --env=TEST.
• Use scoped keys: a Stripe agent API key with only the permissions needed, Paddle OAuth that starts read-only, Square DISALLOW_WRITES=true, a dedicated Adyen webservice user with limited roles.
• Load fewer tools where you can: Adyen --tools. Avoid loading tools you do not need.
• Confirm before refunds: Stripe enforces this for refunds when the agent acts with your user credentials. PayPal, Paddle, Square and Adyen do not say they do, so turn on your client's tool approval and read each write call.
• Never put live keys in committed files. Reference an environment variable, as Stripe's .mcp.json example does with ${AGENT_API_KEY}, or use OAuth.
• Revoke access you no longer use. Stripe lists OAuth sessions in your user settings.

• SaaS subscriptions with tax handled for you: Paddle. As merchant of record it collects and files sales tax, for 5% + 50¢ per checkout transaction.
• Marketplaces, one-off payments or the broadest API: Stripe. Lower card fee (2.9% + 30¢), Connect support through the Stripe-Account header, and refund confirmation when the agent acts with your user credentials.
• Buyers who expect PayPal or Venmo: PayPal. Its tools cover orders, invoices, subscriptions and disputes.
• In-person sellers already on Square, or enterprise teams on Adyen: use their servers, with the limits noted above.
• Details on this page were checked against vendor docs and pricing pages on 2026-10-23.

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