n8n

Google Sheets API allows around 100 reads per 100 seconds per user. In n8n: add a 1-second delay between items, enable batching on the node, or switch to a service account with its own quota.

n8n 404 on webhooks is usually a wrong URL path, missing production webhook activation, or an n8n_disable_production_main_process flag. Steps to find and fix each cause.

ECONNREFUSED means the target service is not listening on that port, or n8n is in Docker and cannot reach localhost. Replace localhost with host.docker.internal, verify the port, and check firewall rules.