Things I'm useful for

• App Store rescue — your iOS/Mac app keeps getting rejected, you can't tell why, and you've burned 3+ resubmissions. I've shipped 53 apps + survived ~50 rejections; I encoded the rulebook into apple-presubmit-audit and PreReviews. Diagnostic + fix in 1–2 sessions.
• AI agent reliability & cost audits — for teams whose Claude / OpenAI bill grew faster than their eval harness. Per-subagent / per-model / per-project attribution, MCP server review, runaway-call diagnosis. My own 12-subagent pipeline runs at ~$13K/wk shadow cost on a $200/mo Max plan (250× leverage); claude-agent-ledger (npm, MIT) is the open-source instrument. Typical scope: 1-week audit + remediation plan.
• Indie iOS coaching — SwiftUI / SwiftData / StoreKit 2 / ASO at scale. Async over email or 1-hour video sessions.
• Reliability code review — your service hits weird edge cases at scale; 6 yrs deep on a hypervisor + 53-app pipeline gives me a long-tail-bug reflex.

How I work

• Async-first. GMT+8. I read email and respond within ~24h on weekdays. Real-time calls land in 9pm–11pm China time (= US-PT afternoon).
• Scope-bounded. 1–4 week engagements typical. I won't take on anything that requires daily standups or full-time hours — that's not what side work is.
• Default answer is "probably no." Not flexing — the day job + 53-app pipeline + open-source already fill most weeks. But if it's interesting and small, the answer flips fast.
• Invoiced via PingPong / Wise — I work with Western indie founders + small SaaS teams routinely. Standard contractor paperwork (Deel / Remote.com / direct) all fine.

Stack I bring to bear

• Infra: Linux, KVM/QEMU, virtio, cgroups/namespaces, Prometheus, Go, Python
• Mobile / desktop: Swift, SwiftUI, SwiftData, StoreKit 2, AppKit
• Web / tooling: TypeScript, Bun, Node, Astro, Next.js
• AI / agents: Claude Code SDK, MCP server development, agent observability

Verifiable signals

• 53 live iOS apps + 1 Mac app on the App Store. Browse the full catalog with App Store IDs.
• github.com/XJM-free — public commit history, 3 OSS published (most repos private per Apple Developer Program rules).
• npm/claude-agent-ledger — my package, weekly download counts public.
• prereviews.app — Mac App Store devtool.
• Public technical writing at jiexiang.dev — every post has a number or a postmortem in it.

Reach me

Email: jie.xiang.jm@gmail.com · Bluesky: @jiexiang.dev · GitHub: XJM-free

One-line description of the problem + your timeline gets the fastest reply.