# tanchao.xyz — LLMs.txt
# Per https://llmstxt.org spec

# tanchao.xyz

> tanchao.xyz is Chao Tan's engineering blog on data governance, data platform protection, AI system security, and performance engineering. Practical field notes from 18 years building production systems at Snowflake, Amazon Alexa, HSBC, and eBay — with emphasis on controls, evidence, drift, and what actually breaks in production.

## About

- [About Chao Tan](https://tanchao.xyz/about/): Bio, patents, domain expertise, and contact
- [Now](https://tanchao.xyz/now/): Current focus areas
- [Work / Hire me](https://tanchao.xyz/hire-me/): Professional background with structured data for recruiting bots
- [Uses](https://tanchao.xyz/uses/): Tools and tech stack

## Posts

- [Data Protection in BigQuery: A Field Guide](https://tanchao.xyz/posts/2026/05/17/bigquery-data-protection/): How BigQuery layers IAM, policy tags, dynamic masking, RLS, authorized views, VPC Service Controls, CMEK/EKM, and the Knowledge Catalog into a defensible data protection posture — and what it leaves to you.
- [How Modern Data Platforms Protect Data](https://tanchao.xyz/posts/2026/05/13/how-modern-data-platforms-protect-data/): A short, practical overview of how BigQuery, Databricks, Immuta, and Lake Formation protect data in practice — and where teams usually get exposed.
- [AI Coding Interview Rubrics](https://tanchao.xyz/posts/2026/05/07/ai-coding-interview-rubrics/): What separates a competent AI-assisted engineer from someone who just autocompletes? A framework for evaluating the skills that actually matter.
- [Monthly retro — March 2024](https://tanchao.xyz/posts/2024/03/29/monthly-retro/): What I shipped, what I'm focused on next, and what I learned in March 2024 at Snowflake.
- [TILs at Snowflake](https://tanchao.xyz/posts/2024/03/28/snowflake-til/): Two years of learnings at Snowflake — on performance, product thinking, and technical leadership.
- [First month retro](https://tanchao.xyz/posts/2022/10/05/hello-snowflake/): When I left Amazon, I scheduled 1-1s with leaders and friends to farewell (virtually) in person. During these chats, mostly my gratefulness to work with them an
- [Chao's Habits](https://tanchao.xyz/posts/2022/08/03/chaos-habits/): Five engineering habits to keep after leaving Amazon: own with a growth mindset, dive deep on operations, learn systems the hard way, prioritize tech debt, and ship your own things first.
- [Design Philosophy](https://tanchao.xyz/posts/2022/06/16/design-philosophy/): 1. Abstract 1. Flexible to change 1. S
- [Driver vs Coder](https://tanchao.xyz/posts/2022/03/28/driver-coder/): Yesterday I drove to my friend's house for a gathering, during the intersection of I485 & I90, a car speeded up, passed me and then merged in my lane without tu
- [API](https://tanchao.xyz/posts/2022/02/24/api/): - Never break backward compatibility. 	 Our contract with our customers is sacrosanct. We will never violate that contract.   - Work backward from customer use 
- [Engineering Excellence](https://tanchao.xyz/posts/2022/02/03/e-e/): Amazon has a famous concept called OE which is short for Operational Excellence. The other term not so famous, is EE that short for Engineering Excellence. EE f
- [Amazon Gems](https://tanchao.xyz/posts/2022/01/20/amzn-gems/): There are some good habits that I learnt and practices and established during at Amazon.
- [Good reads](https://tanchao.xyz/posts/2022/01/13/good-reads/): There is a question in Zhihu (aka. Quora in China) asked "what's the programming book made you WoW?". That's the trigger that I should allocate a post for those
- [supertan's principles](https://tanchao.xyz/posts/2021/12/07/principles/): Seven personal engineering principles distilled from Amazon: automation, proactivity, deliver-small-deliver-fast, highest standard, dynamic problem-solving, think big, and operational excellence.
- [Tech recordings at Amazon](https://tanchao.xyz/posts/2021/07/31/tech-records/): A running log of technical learnings, career reflections, and engineering principles from my years at Amazon Alexa.
- [focus on fault tolerance instead of perfectionism](https://tanchao.xyz/posts/2021/07/15/basketball-lesson/): Quote from my linkedin post (https://www.linkedin.com/posts/tanchaokidsplay-designpattern-activity-6821708682187935744-7rTJ):
- [SDE Good Reads](https://tanchao.xyz/posts/2021/07/13/sde-good-reads/): 1. https://sre.google/sre-book/service-level-objectives/ 2. https://www.atlassian.com/incident-management/kpis/sla-vs-slo-vs-sli
- [hello world again](https://tanchao.xyz/posts/2021/07/06/hi-again/): time flies as it always
- [Behavior Questions](https://tanchao.xyz/posts/2018/04/10/behavior-question/): - Self introduction   - Purpose:   - Measure:   - Answer: - Why choose this company?   - Why this team?   - Any target team?   - Any target field? - Give me a p
- [Coding Questions](https://tanchao.xyz/posts/2018/04/10/coding/): - 2Sum   - Core complexity:   - Key idea:   - Constraints and edge case:
- [System Design Questions](https://tanchao.xyz/posts/2018/04/10/system-design/): - Voting system   - Basic Problem:   - Followups:     - How to scale? Huge volume.     - How to present realtime results?     - Rule of valid vote change, say e
- [How to seek job?](https://tanchao.xyz/posts/2016/08/10/how-to-seek-job/): 以下内容转载自：Random Mumble，初衷是方便国内朋友浏览。   如有不便请与我联系删除，谢谢。   感谢原作者分享！
- [First Setups and Issues with Thursday](https://tanchao.xyz/posts/2016/07/13/thursday-init/): alias pem file and command

## Notes

- [interestingly, i turned back to Jira heavily now, my agent n…](https://tanchao.xyz/notes/substack-c-266185177/)
- [one side you boost implementation and code generation, on th…](https://tanchao.xyz/notes/substack-c-263963543/)
- [Addictive self destruction.](https://tanchao.xyz/notes/substack-c-263143969/)
- [you need pirates, who are curious and brave enough to explor…](https://tanchao.xyz/notes/substack-c-262917579/)
- [the more i tailor my dev-agent, the more i realize how claud…](https://tanchao.xyz/notes/substack-c-262293729/)
- [there is a self-enforcement loop to quarantine myself to int…](https://tanchao.xyz/notes/substack-c-262312355/)
- [if you don’t read carefully and pay attention, then a typica…](https://tanchao.xyz/notes/substack-c-262354676/)
- [现在很多信息的流动必须promo到多模态](https://tanchao.xyz/notes/substack-c-261859670/)
- [I count with my little boy, just realize 10 starts from 1, 2…](https://tanchao.xyz/notes/substack-c-260139653/)
- [it’s really interesting to see how human-like these agent ha…](https://tanchao.xyz/notes/substack-c-259644888/)
- [it’s so easy, and much easier to distract me into something …](https://tanchao.xyz/notes/substack-c-258953314/)
- [they say it’s the best time to innovate, i say no; it’s the …](https://tanchao.xyz/notes/substack-c-259033323/)
- [1 year passed, I still remember how excited I was to build m…](https://tanchao.xyz/notes/substack-c-258523675/)
- [Agentic blogger.](https://tanchao.xyz/notes/substack-c-257864041/)
- [Learning is a natural result of doing.](https://tanchao.xyz/notes/substack-c-255425345/)
- [I want to watch live, just to avoid the clippers the directo…](https://tanchao.xyz/notes/substack-c-255451770/)
- [一叶障目](https://tanchao.xyz/notes/substack-c-254757086/)
- [人有多大胆 地有多大产](https://tanchao.xyz/notes/substack-c-252080270/)
- [The interesting fact is that good enough.](https://tanchao.xyz/notes/substack-c-251375743/)
- [you cannot fool your customers, particularly when your custo…](https://tanchao.xyz/notes/substack-c-251020297/)
- [All notes (105)](https://tanchao.xyz/notes/): Short-form thoughts and learnings

## Projects

- [Customize OpenAI privacy-filter for Snowflake semantic_categories](https://tanchao.xyz/projects/privacy-filter-customization/): Fine-tune OpenAI's privacy-filter model on Snowflake's semantic_categories taxonomy, then evaluate against a hand-labeled holdout.

## Machine-readable

- [RSS Feed](https://tanchao.xyz/rss.xml): All posts as RSS 2.0 with full content
- [Content JSON](https://tanchao.xyz/api/content.json): Posts, notes, and projects as structured JSON
- [Posts JSON](https://tanchao.xyz/api/posts.json): Posts metadata
- [Notes JSON](https://tanchao.xyz/api/notes.json): Notes metadata
- [Projects JSON](https://tanchao.xyz/api/projects.json): Projects metadata
- [LLMs full text](https://tanchao.xyz/llms-full.txt): Full rendered content of posts and notes
- [Sitemap](https://tanchao.xyz/sitemap-index.xml): XML sitemap
- [Search](https://tanchao.xyz/search/): Full-text search across the site