Eight Months in SDS

May–December 2025

PythonTA sits at the heart of UofT’s intro CS pipeline, running AST transforms, style checks, and feedback generation for thousands of students.

MarkUs is the production-grade Rails/Postgres/React platform that handles assignments, submissions, annotations, rubrics, and grading for entire departments.

After eight months in SDS, I’ve touched ASTs, Rails associations, SQL functions, i18n strings, frontend JS event models, and 50+ RSpec files. I now understand what real production engineering feels like.

The Series

1. PythonTA — My introduction to production codebases
2. MarkUs: Testing — Controller tests and RSpec patterns
3. MarkUs: Framework — Rack deprecation fixes
4. MarkUs: Performance — Fixing N+1 queries
5. MarkUs: Models — Foreign key cascade architecture
6. MarkUs: Visibility I — Scheduled assessment visibility (backend)
7. MarkUs: Visibility II — Scheduled assessment visibility (frontend)
8. MarkUs: Touch — Tablet annotation support
9. Reflections — What I learned and where I’m going

Acknowledgments

Everything in this series was built under the guidance, code reviews, and (sometimes humbling) comments from David Liu and the SDS team. Their feedback shaped how I write, think, and communicate as an engineer.

This retrospective is a thank-you note as much as it is a summary.