The year is 2025. You’re writing tests for networking code in your Swift app. You could hit the live API, but then your tests are slow, flaky, and fail whenever that third-party service has a bad day. You could stub URLSession, but then you’re maintaining two implementations of your networking layer...

Here's a way to switch audio output to a bluetooth speaker using terminal tools.On Pop_OS, I have a utility called bluetoothctl that facilitates communication with bluetooth devices.This utility opens its own repl when typing bluetoothctl:❯ bluetoothctl Agent registeredFrom inside this repl, we can ...

Authors: Svyatoslav Kryukov, Backend Engineer, and Travis Turner, Tech EditorTopics: Rails, React, JavaScript, Tailwind CSSWe want to make Inertia.js more popular within the Rails community, so we've started a project to provide both Rails-specific community docs and a set of tools for simply integr...

Modern concurrent data structures increasingly rely on atomic operations to avoid the overhead of locking. A valuable but under-utilized technique for maximizing the effectiveness of atomic operations is bit packing—fitting multiple logical fields into a single atomic variable for algorithmic simpli...

Did a few cat pics tonight!

Adding multi-tenancy to a DDD Rails app Many businesses when they set out to create some software they need, don’t know that one day, they might need multi-tenancy. This is one of the features, that is not easy for programmers to add later easily. It might take months or even years. Let me describe ...

Luciano Mammino's 2025 year in review: releasing the fourth edition of Node.js Design Patterns, progressing on Crafting Lambda Functions in Rust, approaching 5 years at FourTheorem, public speaking, AWS Bites podcast, open source contributions, and some major personal milestones.

Here is something I have noticed about my projects and using Copilot lately. When I add a new NPM dependency, I also update the Copilot instructions file to include examples of how I want to use that dependency in my tests.For example, let's say I need to test if item prices on the inventory page ar...

2025 was the year Warp stopped being “just a terminal” and became an Agentic Development Environment (ADE): a platform where the default unit of work shifted from ‘open file, type code’ or ‘open terminal, type command’ to write a ‘prompt, steer agents, and ship with confidence’. The numbers tell par...

If your product data was a person, they'd basically be unemployed. They could get picked up in the occasional "freelance" query, but would ideally be…

A multi-tenant system can be used by many customers and for each of them it looks like they are the only ones. Think about AWS, for example: the account is isolated from all other accounts, and apart from the account ID there is no indication that anybody else is using that platform. The obvious rea...

This article collects small, self-contained, and practical examples for working with std::chrono calendar types. The previous blog post - see Exploring C++20 std::chrono - Calendar Types - C++ Stories - focused on the building blocks: calendar types, operators, and arithmetic rules. In this post, we...

For the past ten years, I've been blogging about writing test automation on this blog, writing toy projects to help practice what I am doing on the job, writing articles and courses about test automation, and storing coding projects at https://github.com/tjmaher.Starting in January, my next project ...

If your application has user accounts, authentication touches everything: who can access what, what data belongs to whom, and how your system behaves when sessions expire or credentials are invalid. Auth is also one of the most commonly mocked components in test suites. The reasoning makes sense. Re...

At RailsWorld earlier this year, I got nerd sniped by someone. They asked “why can’t Bundler be as fast as uv?” Immediately my inner voice said “YA, WHY CAN’T IT BE AS FAST AS UV????” My inner voice likes to shout at me, especially when someone asks a question so obvious I should have thought of it ...

TL;DR: How Vinted standardizes large-scale decentralized data pipelines. When we started migrating Vinted’s data infrastructure to the cloud, we set out to create a decentralized way of working. The idea was simple: teams know their data best, so they should be fully empowered to build, own, and ope...

A PostHog recipe for people whose users keep leaving the table. Prep time ~30 minutes setup, ~1 week of data Difficulty Beginner-friendly Yields One…

I know, I'm late as fuck to the party. The thing is, I'm not a fan of Flatpak, or Snap, or even Dockerizing things for the sake of using containers. I like to stick as close to the system's package manager as possible. This is why I like Arch Linux and more specifically the AUR (Arch User Repository...

JavaScript was an elegant prototype-based class-free language until TypeScript and ES6 classes ruined it.

As a child of the 80s, I have distinct things that I associate with successful people. We’re talking the age of shows like Lifestyles of the Rich and Famous, Dallas, and Dynasty. Sports like tennis, racquetball, golf, and sailing. People in their white short shorts, and polo shirts, with a headband....

"A black hole in his soul?" "A self-reinforcing memetic attractor, if you prefer. Plot it in...

Before C++20, <chrono> gave us a solid foundation for working with clocks, durations, and time points - but it didn’t really know anything about the civil calendar. If you needed to represent “March 15”, check whether a date is valid, compute “the third Monday of November”, or add a few months to a ...

Loading skeletons are displayed while the real data is loading. For example, the login passwords are displayed after 1 second in the GIF below, and the loading skeleton is displayed first.The skeleton itself is simple, just a DIV with some gradient CSS.src/pages/Login.jsx1234567891011121314151617181...

eBay’s cash advances helped a Filipino immigrant’s gig selling sneakers turn into a lucrative business.

As we enter the funny week-without-time between Christmas and New Year, it's a great time to reflect. Here's a framework I like to use.

As we enter the funny week-without-time between Christmas and New Year, it's a great time to reflect. Here's a framework I like to use.

Codeforces Global Round 31 last Friday wrapped up the 2025 Global Round series (problems, results, top 5 on the left, analysis, serie standings that use the "sum all 3" instead of the actual "sum 2 best out of 3" scoring system). I spent way too much time on implementation and debugging once again, ...

Staging environments drift. The fix is obvious: refresh staging from production regularly. The problem is that “regularly” and “multi-hour database copy” don’t mix well. Three traditional approaches pg_dump / pg_restore This simple route works for small databases and not critical workloads, e.g. a d...