Developers & AI agents

Payments your AI assistant can run

MerchantLink is a native MCP server with a matching REST API. Let Claude or your own agents create invoices, send payment links and follow the money, with limits and approvals you control.

Get an API key OpenAPI spec

MCP server

Connect an assistant in one line

MerchantLink speaks the Model Context Protocol over Streamable HTTP. Any MCP client can discover its tools, and each key only sees the tools its scopes allow.

Claude Code

claude mcp add --transport http merchantlink https://www.merchantlink.ai/api/mcp \
  --header "Authorization: Bearer ml_sk_…"

Any MCP client (JSON config)

{
  "mcpServers": {
    "merchantlink": {
      "type": "http",
      "url": "https://www.merchantlink.ai/api/mcp",
      "headers": {
        "Authorization": "Bearer ml_sk_…"
      }
    }
  }
}

REST API

The same operations over plain HTTP

Integer cents, predictable JSON, Stripe-style idempotency keys, and pay links and QR codes in every response.

Create an invoice

curl https://www.merchantlink.ai/api/v1/invoices \
  -H "Authorization: Bearer ml_sk_…" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: 7f3c9a" \
  -d '{
    "customer": { "name": "Jane Smith", "email": "jane@example.com" },
    "items": [{ "description": "Logo design", "unit_amount_cents": 45000 }],
    "due_date": "2026-10-07"
  }'

200 OK

{
  "id": "inv_…",
  "object": "invoice",
  "number": "INV-1012",
  "status": "open",
  "total_cents": 45000,
  "amount_due_cents": 45000,
  "pay_url": "https://www.merchantlink.ai/pay/v7nkneh7ts",
  "qr_code_url": "https://www.merchantlink.ai/api/qr/v7nkneh7ts"
}

202 Accepted: over a limit or needs approval

{
  "status": "pending_approval",
  "approval_id": "ai_…",
  "message": "This API key requires approval before contacting customers…"
}

Guardrails for autonomous agents

Give agents real power, safely

Every API key is a policy. Decide what an agent may do, how much it may bill, and when it must ask you first.

Scoped keys

Ten scopes, from links:read to refunds:write. Read-only and full-access presets included.

Amount limits

Invoices or links above a key’s ceiling become approval requests instead of executing.

Approval before contact

Optionally require your OK before an agent emails or texts a customer. Agent refunds always need approval.

Audit trail

Every agent action is recorded with the key that made it, alongside human and AI actions.

Idempotency

Retry any POST safely with an Idempotency-Key; the original response is replayed.

Event feed

Poll list_events with a cursor to react to payments, views and customer replies.

OpenAPI 3.1

Generated from the same schemas that validate every request, so it never drifts.

llms.txt

A plain-text guide at /llms.txt teaches any model how to use MerchantLink.

Reference

20 tools, one catalogue

Identical over MCP and REST. Money is always integer cents.

Tool	Scope	What it does
create_payment_link	links:write	Create a shareable payment link with a QR code. type "fixed" = one-time payment of amount_cents; "donation" = payer picks from suggested_amounts or enters any amount; "open" = payer enters any amount. Returns the pay url and qr_code_url.
list_payment_links	links:read	List standalone payment links (fixed, donation, open) with amounts collected.
get_payment_link	links:read	Get a payment link by id.
set_payment_link_status	links:write	Deactivate a payment link so it can no longer be paid, or re-activate it.
create_invoice	invoices:write	Create an itemized invoice. Pass customer_id, or customer {name, email, phone} to match/create one. Amounts are integer cents. Every invoice gets a pay_url and qr_code_url. Use send_payment_request afterwards to email/text it.
list_invoices	invoices:read	List invoices, optionally filtered by status (draft, open, partially_paid, paid, void, overdue) or customer_id.
get_invoice	invoices:read	Get an invoice with line items, balance due, pay_url and payments.
finalize_invoice	invoices:write	Finalize a draft invoice so it becomes payable.
void_invoice	invoices:write	Void an unpaid invoice. Its payment link stops accepting payments.
send_payment_request	messages:send	Email and/or text the pay link for an invoice or payment link to the customer. Texts only go to customers who opted in themselves on the payment page or the merchant's text sign-up page; otherwise use email. If the API key requires approval, the send is queued for the merchant to approve.
create_customer	customers:write	Create a customer. Phone numbers in E.164 (+15551234567).
list_customers	customers:read	List or search customers by name, email, company or phone.
get_customer	customers:read	Get a customer by id.
list_payments	payments:read	List payments (most recent first), optionally by status or invoice.
get_payment	payments:read	Get a payment by id.
refund_payment	refunds:write	Request a full or partial refund (amount_cents). Refunds requested by agents always require merchant approval.
get_account_summary	insights:read	Revenue collected in the last N days, outstanding and overdue balances, and the probability-weighted collections forecast for the coming weeks.
list_events	insights:read	Poll the account event log (payment.succeeded, invoice.paid, invoice.viewed, message.received, ...). Pass after_seq from the previous call to get only new events.
get_approval	insights:read	Check whether the merchant approved an action this agent requested (status: proposed, executed, rejected, failed).
list_pending_approvals	insights:read	Actions waiting for the merchant to approve (AI-drafted reminders, agent requests...).

Full schemas in the OpenAPI spec and llms.txt.

Send your first payment link today

Every account starts with a built-in sandbox, so you can create invoices, send links and take test payments before you connect a processor.

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