Indie developer / Full-stack engineer
Self-employed · Indie Hacker
2023 - Present
- One person running the whole chain: deciding what's worth building, picking the stack, ingesting data, writing backend services, building the interface, and keeping it alive in production — nothing outsourced.
- I prefer products that can be verified: get the data flowing and the metrics computing first, argue about how it looks later.
- TypeScript is the spine. Node handles ingestion and scheduling, Postgres carries ledgers and time series, the front end is uniformly React / Next.js.
- My delivery habit is to push operating cost close to zero — if it can be statically hosted, it never gets a server; if it can run on the edge, it never calls home.
TypeScript
React
Next.js
Node.js
PostgreSQL
Docker
LinuxQuant trading & financial data
Self-built research platform
2022 - Present
- Built the market-data and backtesting pipeline from scratch: multi-exchange ingestion, tick and candle storage, indicator computation and signal delivery as one async pipeline.
- What I care about is whether the data can be trusted, not how many strategies exist. Time alignment, adjustment conventions and exchange quirks decide whether a backtest is honest.
- Risk control lives in the data layer: outlier detection, gap filling, delisted-symbol pruning — all resolved at ingestion time.
- Conclusions are stored so they can be reproduced: parameters, data versions and evaluation conventions all leave a trail, so nobody trusts a remembered return figure.
PostgreSQL
JavaScriptNode.js
MongoDBDockerLinuxCross-border e-commerce & growth
Own stores / consulting
2021 - Present
- Sourcing and ad spend across multi-platform store groups: platform back-office data, ad cost and shipping times stitched into one operating dashboard.
- The core work is closing the data loop — sourcing from demand signals, pricing from margin models, restocking from turnover days, all landing in the same tables.
- Built in-house tooling instead of buying SaaS: order aggregation, inventory alerts and profit calculation written by hand. The subscription savings matter far less than owning the data.
- Most of the pain wasn't technical, it was definitions: does a refund count as revenue, is ad spend a cost? Until those agree, every report is wrong.
JavaScriptPostgreSQLNode.jsDocker
AWSGet in touch
Email me at changyuansex@gmail.com , or leave a note below.