A prompt that works on three examples might fail on the fourth. Prompt engineering without testing is guessing. In this article, you will learn how to test prompts systematically, measure quality, and iterate until you get reliable results. This is Article 18 in the Claude AI — From Zero to Power User series. You should know Prompt Engineering Basics before this article. By the end, you will have an eval harness that tests your prompts automatically and a process for improving them. ...

In the previous tutorial, we learned what TypeScript is and why it matters. Now let’s install it and write our first program. By the end of this tutorial, you will have TypeScript installed, VS Code configured, and a working project you built yourself. Step 1: Install Node.js TypeScript runs on Node.js. If you don’t have Node.js installed, download the LTS version from nodejs.org. After installation, verify it works: node --version # v22.x.x or later npm --version # 10.x.x or later If both commands print version numbers, you are ready. ...

TypeScript is everywhere. It became the #1 most-used language on GitHub in August 2025, surpassing Python. It now ranks among the top languages in every major developer survey. If you write JavaScript, TypeScript is no longer optional — it is expected. This tutorial series will take you from zero to confident TypeScript developer. We start here: what TypeScript actually is, and why you should learn it in 2026. What is TypeScript? TypeScript is a superset of JavaScript that adds static types. Every valid JavaScript file is already valid TypeScript. TypeScript just adds extra features on top. ...

In the previous tutorial, we built a web scraper. Now let’s build an automation script — a file organizer that sorts files by type, processes CSV data, and logs everything properly. This is the final project in the Python Tutorial series. It ties together everything: file I/O, dataclasses, error handling, logging, testing, and packaging. By the end, you will have a practical tool you can use every day. What We Are Building A file organizer that: ...

In the previous tutorial, we built a REST API with FastAPI. Now let’s build a web scraper — a program that extracts data from web pages automatically. We will use httpx to fetch pages and BeautifulSoup to parse HTML. By the end, you will know how to extract data, save it to JSON and CSV, and scrape responsibly. When to Scrape (and When Not To) Web scraping is useful for: Collecting data that is not available via an API Monitoring prices, job listings, or news Research and data analysis But check these first: ...

In the previous tutorial, we built a CLI tool with Click and Rich. Now let’s build a REST API — a web API that any frontend, mobile app, or other service can call. We will use FastAPI, the fastest-growing Python web framework. It has automatic documentation, type checking, and built-in validation. By the end of this tutorial, you will have a working Bookmark Manager API. Why FastAPI? Automatic API docs — Swagger UI at /docs (free, no setup) Type-safe — uses Python type hints for validation Fast — built on Starlette and Pydantic (one of the fastest Python frameworks) Async support — native async/await (from Tutorial #18) Pydantic validation — automatic input validation (from Tutorial #10) Install the dependencies: ...

In the previous tutorial, we learned about logging and debugging. Now let’s build our first real project — a command-line task manager using Click for argument parsing and Rich for colored output. This project uses everything we have learned so far: dataclasses, file I/O, error handling, testing, and more. By the end, you will have a working CLI tool you can install with pip install. What We Are Building A task manager that runs in the terminal: ...

In the previous tutorial, we learned about databases with SQLite and SQLAlchemy. Now let’s learn about logging and debugging — the professional way to understand what your program is doing. If you still use print() to debug your code, this tutorial is for you. By the end, you will know how to use Python’s logging module, debug with breakpoint(), and profile your code. Why print() is Not Enough Every beginner uses print() for debugging: ...

In the previous tutorial, we learned about HTTP requests and APIs. Now let’s learn about databases — how to store, read, update, and delete data using Python. We will cover two approaches: Python’s built-in sqlite3 module (no installation needed) and SQLAlchemy (the most popular Python ORM). By the end of this tutorial, you will know how to build data-driven applications. What is SQLite? SQLite is a database that stores everything in a single file. It comes built into Python — no installation, no server, no configuration. It is perfect for: ...

In the previous tutorial, we learned about async/await and asyncio. Now let’s learn about HTTP requests and APIs — how to call REST APIs, send data, handle responses, and build a reusable API client. Almost every Python application talks to an API at some point. Weather data, payment processing, social media, databases — they all use HTTP. By the end of this tutorial, you will know how to make HTTP requests, handle errors, and build a clean API client. ...