Software Engineering

Designing and evolving system architecture is about making informed trade‑offs. This guide provides a practical, opinionated walkthrough of the core concepts, patterns, and decisions you need to build scalable, reliable, and cost‑efficient systems—plus answers to the most common questions engineers and architects ask.

TL;DR Ruff replaces Flake8, Black, isort, and pydocstyle — one tool, 10–100× faster (written in Rust). Install: uv add --dev ruff or pip install ruff. Run: ruff check . (lint) and ruff format . (format). Add pre-commit hooks + GitHub Actions to enforce on every commit and PR. Pair with the Python CI Pipeline guide for the full uv + Ruff + ty setup. Writing clean, readable code is essential for collaboration and maintainability. Linters and formatters help us keep our codebase consistent and easy to understand.

You can create a Python Code Quality CI pipeline using uv, Ruff, and ty within 5 minutes. TL;DR Replace pip + requirements.txt with uv for fast, reproducible installs. Replace Flake8 + Black + isort with ruff — one tool, 10–100× faster. Add ty for type checking (Astral’s faster mypy replacement). Total CI time: ~30s. GitHub Actions config fits in 20 lines. Most of us begin a Python project with high hopes. We set up a clean virtual environment, organize a requirements file, and plan to add a linter—then forget.

A quick, task-oriented Git reference. Pair this with the in-depth guide for concepts and best practices. TL;DR Working tree → git add → Staging area → git commit → Local repo → git push → Remote. Most common daily commands: status, add, commit, push, pull, checkout, merge. Undo staged changes: git restore --staged <file>. Undo last commit (keep changes): git reset HEAD~1. For concepts and workflows, read the full Git guide. Minimal Mental Model # graph LR WD[Working Dir] -- add --> ST[Staging] ST -- commit --> REPO[Local Repo] REPO -- push --> ORI[Origin] ORI -- fetch/pull --> REPO Setup # git --version git config --global user.name "Your Name" git config --global user.email "you@example.com" git config --global init.defaultBranch main Create or Clone # git init git clone <url> Status and Diffs # git status git diff # unstaged git diff --staged # staged vs HEAD Stage and Commit # git add <path> git add -p # interactive hunks git commit -m "feat: message" git commit --amend # edit last commit Branching # git branch git switch -c feature/x git switch main git branch -d feature/x Sync with Remote # git remote -v git fetch git pull # merge git pull --rebase # rebase git push -u origin my-branch Merge vs Rebase # git switch my-branch && git merge main git switch my-branch && git rebase main Resolve Conflicts # git status # edit files, remove markers git add <file> git commit # after merge git rebase --continue # during rebase Stash Work # git stash push -m "wip" git stash list git stash pop Undo Safely # git restore --staged <file> # unstage git restore <file> # discard local edits git revert <sha> # new commit to undo git reset --soft HEAD~1 # keep changes, drop last commit git reflog # find lost commits Tags and Releases # git tag -a v1.0.0 -m "msg" git push --tags Ignore and Clean # echo "node_modules/" >> .gitignore git clean -fdx # dangerous: removes untracked files Authentication (Quick) # # HTTPS + PAT git clone https://github.com/owner/repo.git # SSH ssh-keygen -t ed25519 -C "you@example.com" ssh-add ~/.ssh/id_ed25519 git clone git@github.com:owner/repo.git Conventional Commits (Optional) # feat(auth): add oauth login fix(api): handle null pointer in user service chore(ci): update node to 20 Common One-Liners # # See last commit summary git log -1 --stat # Interactive rebase last 5 commits git rebase -i HEAD~5 # Squash branch onto main git switch my-branch && git rebase -i main Quick PR Flow (GitHub) # git switch -c feat/x # edit, add, commit git push -u origin feat/x # open PR on GitHub See also: the full guide “The Definitive Guide to Version Control with Git and GitHub”.

Version control is the foundation of reliable software delivery. This guide teaches Git from first principles, then layers in practical GitHub workflows used by high-performing teams. You’ll learn the mental models, the everyday commands, and the advanced tools to collaborate confidently without fear of breaking anything.

APIs are the connective tissue of modern products. This guide distills proven practices for API design, security, observability, and reliability—covering the most frequent questions and edge cases teams face in production. Examples use FastAPI and Pydantic v2, but the principles generalize to any stack.

New to APIs? This guide explains core concepts in clear language, then walks you through building a small FastAPI service with essential security and testing tips. When you’re ready for advanced patterns, read the companion: Designing Secure and Scalable APIs — A Comprehensive Guide.