Build with Cursor

LUMX_API_KEY=lumx_sk_sandbox_xxxxxxxxxxxxxxxx
LUMX_ENV=sandbox

.env
.env.local
.env*.local

{
  "mcpServers": {
    "lumx-docs": {
      "url": "https://docs.lumx.io/mcp"
    }
  }
}

Add a stablecoin payments backend that uses the Lumx API. Lumx
connects local banking rails to stablecoins so I can collect, hold,
convert, and pay out money in either form.

Rules
- Read LUMX_API_KEY from environment variables (process.env in Node,
  os.environ in Python, ENV in Ruby, etc.). Never expose it in
  client-side code. Always call Lumx from server routes.
- Pick the base URL from LUMX_ENV. Default to
  https://api-sandbox.lumx.io. Use https://api.lumx.io when LUMX_ENV
  is "production".
- Send every request with the headers:
    Authorization: Bearer ${LUMX_API_KEY}
    Content-Type: application/json
- On non-2xx responses, surface the Lumx error body and HTTP status.
  Do not retry 4xx.

Match the project's existing conventions
- Detect the project's language and framework first, then write
  idiomatic code for that stack (Next.js app router, Remix loaders,
  Express routes, FastAPI routers, Django views, Rails controllers,
  etc.).
- Reuse the project's existing HTTP client, error helper, or
  validation library if one already exists.

Server routes to build
1. POST /api/customers — calls Lumx POST /customers. Body: type
   ("INDIVIDUAL" or "BUSINESS"), name, taxId, country (ISO-3), email.
   Returns the Lumx customer record including verification.link.
2. POST /api/on-ramp — calls Lumx POST /transactions/on-ramp. Body:
   customerId, currency (ISO-3), amount (string). Returns the
   rail-specific deposit instructions.
3. GET /api/transactions/:id — calls Lumx GET /transactions/:id and
   returns the transaction's current status and timeline.

UI to build (only if the project already has a frontend)
- Customer onboarding screen: form that calls POST /api/customers,
  then renders verification.link as a button.
- On-ramp deposit screen: form that picks a customer, sets a
  currency and amount, calls POST /api/on-ramp, then renders the
  returned deposit instructions.

Reference: https://docs.lumx.io

const LUMX_BASE =
  process.env.LUMX_ENV === "production"
    ? "https://api.lumx.io"
    : "https://api-sandbox.lumx.io";

async function lumx(path: string, init?: RequestInit) {
  const res = await fetch(`${LUMX_BASE}${path}`, {
    ...init,
    headers: {
      Authorization: `Bearer ${process.env.LUMX_API_KEY}`,
      "Content-Type": "application/json",
      ...init?.headers,
    },
  });
  if (!res.ok) {
    throw new Error(`Lumx ${res.status}: ${await res.text()}`);
  }
  return res.json();
}

export const createCustomer = (input: {
  type: "INDIVIDUAL" | "BUSINESS";
  name: string;
  taxId: string;
  country: string;
  email: string;
}) => lumx("/customers", { method: "POST", body: JSON.stringify(input) });

export const createOnRamp = (input: {
  customerId: string;
  currency: string;
  amount: string;
}) =>
  lumx("/transactions/on-ramp", {
    method: "POST",
    body: JSON.stringify(input),
  });

export const getTransaction = (id: string) => lumx(`/transactions/${id}`);