I'm Andy Wang, a senior Rails & AI Product Engineer based in Xi'an, China (UTC+8).
Building web software since 2005, primarily Ruby on Rails since 2008, working remotely with US and European teams since 2011.

My work is the product system around model capabilities — multi-stage workflows, application state, retries, human review, evaluation and observability — rather than one-off prompts or demos.

• HexagramCast — creator and primary builder. A traceable I Ching reflection tool: 8 casting methods (4 traditional, 4 deterministic modern), with the input digest, computation trace, moving lines and classical source layers all inspectable. No fortune-telling, no luck scores. English-first, also in 简体中文 and 繁體中文; web, API and browser-extension entry points.

• Rails product systems — greenfield builds and mature codebases I own over the long term
• Complex business workflows — payments and subscriptions, lesson/resource scheduling, marketplaces, CMS and multi-channel publishing, data and reporting, admin and operational tooling
• Multi-party platforms — roles, documents, agreements and state machines, including private-investment onboarding workflows, health-device data portals and vendor marketplaces
• Production AI workflows — structured inputs and outputs, asynchronous state, retries and failure recovery, human review, evaluation, cost control and observability
• Legacy modernization — Rails upgrades, test suites, background processing and third-party integrations

I'm most useful where a product has real users, non-trivial workflows, and a codebase that has to keep working while it changes. Happy to talk about senior AI product engineering, Rails systems, production AI workflow integration, and end-to-end product delivery.

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