Quickstart: handle Credicorp API error responses

The envelope

{
  "error": {
    "type": "validation",
    "code": "invalid_amount",
    "message": "amount must be between 1000 and 150000",
    "request_id": "req_44be1c"
  }
}

type is a broad family (validation, rate_limit, auth, not_found, server). code is a stable machine string. message is human-readable and may change — never branch on it.

One handler for all of them

async function call(url, init) {
  const res = await fetch(url, init);
  const body = await res.json().catch(() => ({}));
  if (!res.ok) {
    const e = body.error || {};
    console.error(`Credicorp ${res.status} ${e.code} (${e.request_id})`);
    throw new ApiError(res.status, e.code, e.message, e.request_id);
  }
  return body;
}

Map status to behaviour

• 400 validation — fix the request, show the field error.
• 404 not_found — the id/key does not exist; render a fallback.
• 409 conflict — usually an idempotency clash; you already have the result.
• 429 rate_limited — back off and retry (see the rate-limit recipe).
• 5xx / 503 server/unavailable — retry with back-off, then degrade gracefully.