Found in: Artemis, JobClass, Diagram, MoreLessons, QR Bracelet, GTMLeads
D1 is serverless SQLite hosted by Cloudflare. It gives you a real SQL database accessible only from your Worker — no connection strings, no connection pooling, no database server to manage. For small apps, it eliminates the entire database operations layer.
A FastAPI + JavaScript SPA can be deployed to GitHub Pages without rewriting frontend code by using a **fetch shim** — a small JavaScript interceptor injected into `index.html` that redirects API calls to pre-generated JSON files and handles filtering, sorting, and pagination client-side. The build...
The vision tagging pipeline uses Qwen2.5-VL (a 7B-parameter vision-language model) to classify image attributes. Running the real model requires a GPU, takes seconds per image, and produces non-deterministic outputs. The full pipeline — config loading, tagging, derived label computation, DB persiste...
When serving DuckDB through a multi-threaded web framework (FastAPI/uvicorn), never share a single connection object across concurrent request handlers. Instead, call `conn.cursor()` to create a per-request cursor. DuckDB's Python driver does not support concurrent queries on the same connection fro...
Any frontend page that fires multiple `fetch()` calls via `Promise.all()` is an implicit concurrency test for the backend. If your API endpoints work individually via `curl` but fail when the browser loads a page that hits them simultaneously, you have a shared-state concurrency bug — not a data or...
Mock-based tests validate your code's logic, not your assumptions about the external API. When an adapter passes all mock tests but fails against the real API, the bug is almost always in the mock — you encoded incorrect assumptions about field names, response structure, or protocol behavior.
For a full-stack application built from scratch, a strict bottom-up phase order — schema, models, data, services, pipeline, API, UI, export — with one commit per phase and a green test suite at each boundary, produces a codebase where every layer is testable in isolation and integration bugs surface...
When building a multi-phase system, track progress at the row level within each phase (Open → Started → Completed with timestamps), commit only when an entire phase is green, and never batch multiple phases into one commit. This granularity makes it possible to resume mid-phase, measure velocity, an...
In a split-stack project (separate frontend and backend processes on different ports), configure the frontend dev server to proxy API requests to the backend rather than hardcoding backend URLs or relying on CORS alone. The proxy eliminates cross-origin issues during development, keeps the frontend...
When building an entity extraction pipeline, implement rule-based heuristics first and defer LLM-assisted extraction until the deterministic baseline is tested and measured. The rule-based layer gives you a reproducible, cost-free, fast foundation that LLM extraction can extend — not replace.
A GitHub Actions workflow that deploys to GitHub Pages will fail on the first run if Pages is not enabled in the repository settings. The workflow will build successfully but the deploy step returns a 404 — "Ensure GitHub Pages has been enabled." This is a configuration prerequisite, not a code bug,...
A server-side web application can be deployed to a static hosting platform by pre-rendering every page and API response as files, then injecting a JavaScript fetch shim that transparently redirects API calls to the corresponding JSON files. The application's JavaScript never knows it's running on a...
A web application that shows buttons, links, or filters for data that does not exist creates a worse experience than one that simply omits them. Every UI element that implies data availability must be backed by a runtime or build-time check that the data actually exists.