Exponential retries

API calls can fail for transient reasons: network timeout, rate limit (429), or an isolated upstream 5xx. The recommended strategy is to retry with exponential backoff + jitter, always reusing the same Idempotency-Key so a retry that did reach the server doesn’t generate a duplicate document.

Full implementation for Node.js with axios. Note that 4xx errors other than 429 aren’t retried: they indicate a problem with the request that no retry can fix.


import axios from 'axios';
 
async function emitirRobusta(facturaData) {
  const idempotencyKey = crypto.randomUUID();
  const maxReintentos = 5;
 
  for (let intento = 0; intento < maxReintentos; intento++) {
    try {
      const { data } = await axios.post(
        'https://api.pos.lxsyscr.com/api/v1/facturas',
        facturaData,
        {
          headers: {
            'X-Api-Key': process.env.LXS_API_KEY,
            'Content-Type': 'application/json',
            'Idempotency-Key': idempotencyKey
          },
          timeout: 30000
        }
      );
      return data;
    } catch (err) {
      const status = err.response?.status;
 
      // Final errors: do not retry
      if (status >= 400 && status < 500 && status !== 429) {
        throw err;
      }
 
      // Last attempt
      if (intento === maxReintentos - 1) throw err;
 
      // Backoff
      const retryAfter = err.response?.headers['retry-after'];
      const waitMs = retryAfter
        ? parseInt(retryAfter) * 1000
        : Math.min(1000 * Math.pow(2, intento), 30000) + Math.random() * 1000;
 
      await new Promise(r => setTimeout(r, waitMs));
    }
  }
}

If the server returns the Retry-After header, it must always be respected: it takes priority over your own backoff calculation. See also error codes and idempotency.