Hi, I’m Xueqi Liu, an independent full-stack engineer specializing in production n8n/API reliability, TypeScript, Node.js, and PostgreSQL. I turn vague “this workflow randomly breaks” problems into reproducible failures and failure-tested fixes. My public Reliability Lab covers idempotency, bounded retries, durable state, dead-letter recovery, and 51 acceptance tests. Fixed scopes: $95 diagnosis, $250 one-path hardening, $450 API integration slice. Client-controlled deployment; async worldwide.