curl --fail-with-body -sS -X POST 'https://api-testnet.lumeus.dev/billing/checkout' \
  -H "Authorization: Bearer $LUMEUS_API_KEY" \
  -H 'Content-Type: application/json' \
  -d '{"plan":"growth"}'

// Node 18+ (ES module)
const res = await fetch('https://api-testnet.lumeus.dev/billing/checkout', {
  method: 'POST',
  headers: {
    Authorization: `Bearer ${process.env.LUMEUS_API_KEY}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify({
    "plan": "growth"
  }),
});
console.log(res.status, JSON.stringify(await res.json(), null, 2));

import json
import os

import requests

res = requests.post(
    "https://api-testnet.lumeus.dev/billing/checkout",
    headers={"Authorization": f"Bearer {os.environ['LUMEUS_API_KEY']}"},
    json={
        "plan": "growth"
    },
    timeout=30,
)
print(res.status_code, json.dumps(res.json(), indent=2))

{
  "url": "https://checkout.stripe.com/c/pay/cs_test_0000"
}

{
  "code": "invalid_request",
  "error": "plan must be starter, growth or scale",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}

{
  "code": "unauthorized",
  "error": "missing credentials",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}

{
  "code": "forbidden",
  "error": "this API key is read-only; use a full-access key or a signed-in session",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}

{
  "code": "method_not_allowed",
  "error": "method GET is not allowed on /billing/checkout; allowed: POST",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}

{
  "code": "conflict",
  "error": "this workspace already has a subscription; change plans with POST /billing/subscription or manage it in the billing portal",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21",
  "reason": "subscription_exists"
}

{
  "code": "rate_limited",
  "error": "rate limit exceeded",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}

{
  "code": "internal_error",
  "error": "could not start checkout",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}

{
  "code": "unavailable",
  "error": "billing is not enabled",
  "request_id": "req_6f1c2a9b0e4d4c7a8b3f5e21"
}