Technical Software Engineer Leader building correctness-critical systems — money movement, data pipelines, and the boring infrastructure that has to be right when it's 3am and a customer is watching.

I care about the unglamorous parts: invariants enforced at the boundary, writes that are idempotent under retry, and systems you can actually reason about under failure.

Designing and shipping distributed backend systems where data integrity is non-negotiable — payments/ledgers, billing, and event-driven platforms. I like problems where "eventually consistent" has to be paired with "provably never wrong."

• Deepening TypeScript/Node and Python across the full stack.
• Writing about ledger/accounting-system design (the hard part isn't the code, it's the invariants).
• Reading about distributed-systems correctness, DB internals, and event sourcing.

Engineer Manager / Senior / Staff Software Engineer roles — backend, platform, or payments. Remote or San Francisco Bay Area, or Souther California. If you're building systems where correctness matters, let's talk.

• ledger-ts — a double-entry ledger with database-enforced invariants: append-only log, idempotent writes, deferred constraint triggers, transactional outbox. 40 tests including a 400-op concurrency fuzz, running on embedded Postgres (PGlite) and real Postgres in CI.
• resilient-fetcher — concurrency resilience in pure stdlib Python: token-bucket rate limiting, backoff with jitter, a circuit breaker, and a batch-level retry budget. 27 deterministic tests (fake clock, injected transport — never touches a socket or sleeps a real second).

• GitHub: @ellen333712
• LinkedIn: tian-y-17397b60
• Email: use the GitHub profile email (reply via issues on my repos works too)

"The log is the truth; everything else is a projection."