- Flask – REST API
Introduction A REST API (Representational State Transfer Application Programming Interface) is a software architectural style that defines a set of constraints for building web services. REST APIs communicate over HTTP, use standard methods (GET, POST, PUT, DELETE) to perform operations on…
- Flask – Forms & Validation
Introduction Forms are the primary interface between your users and your application. Every login page, registration flow, search bar, checkout form, and settings panel depends on form handling done right. Get it wrong and you open the door to data corruption, security vulnerabilities, and…
- Flask – Introduction & Setup
Introduction Flask is a lightweight WSGI web application framework for Python. Created by Armin Ronacher in 2010, it started as an April Fools’ joke that merged two libraries — Werkzeug (a WSGI toolkit) and Jinja2 (a template engine) — into a single package. The joke turned out to be genuinely…
- Flask – Routes & Templates
Introduction Routing and templating are the two pillars of every Flask application. Routes map incoming HTTP requests to Python functions, and templates turn raw data into HTML that browsers can render. If you understand these two systems deeply, you can build anything from a single-page prototype…
- Back-of-the-Envelope Estimation
The step most candidates skip and most interviewers weight heavily. Powers of two and the latency numbers worth memorising, then the arithmetic that turns "design Airbnb" into concrete QPS, storage and bandwidth figures — worked end to end from real row counts. How to size a cache, when a number tells you the design is wrong, and why being an order of magnitude out is fine but a thousand times out is not.