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Practical lessons from software development, cloud, technical leadership and AI. Written by the people who do it every day.

Featured Software Development
6 min read

Czech Bluetooth Tech Among TIME's Best Inventions 2025

When TIME Magazine selected Evenflo's smart car seat as one of its Best Inventions of 2025, it was recognition for Czech developers. We built the IoT app powering it.

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Software Development

Node.js Event Loop: Practical Overview and Best Practices

A practical deep-dive into the Node.js Event Loop – covering macrotasks, microtasks, Worker Threads, starvation, and real code challenges to test your understanding.

6 min read
Software Development

Why code quality pays off: How Biome helped us build faster, cleaner TypeScript projects

Code quality is not the KPI clients usually look for, but at Cookielab we believe it's a must. We share how we use Biome with a strict custom configuration to enforce safety, performance, and developer experience across all our TypeScript projects.

4 min read
Inside Cookielab

One of TIME's Best Inventions of 2025 runs on Czech software

TIME magazine included Evenflo's SensorySoothe in its Best Inventions of 2025 list – and the app behind it was built by us.

3 min read
Software Development

Is your Android app DDoSing your backend?

If your Android app calls your backend in Application.onCreate and supports Firebase push notifications, you might unknowingly be triggering thousands of API calls every time a notification is delivered – even when no user is present.

4 min read
Inside Cookielab

SlackTiquette: how to communicate on Slack effectively

8 practical tips we use at Cookielab to keep Slack clear, fast, and stress-free – feel free to steal them.

4 min read
Software Development

iOS Cookie Crumbs: May the force (unwrap) not be with you

Force unwrapping optionals in Swift is a double-edged sword. Here's when it's fine – and when it will crash your app.

3 min read
Software Development

Package Managers Comparison: Yarn, NPM, PNPM

A detailed look at the three most popular JavaScript package managers. We break down hoisting, Plug'n'Play, symlinks, and CorePack – so you can make an informed choice for your next project.

5 min read
Software Development

Subtleties of Software Testing (Plus a Practical Example)

Frontend developer Ondřej Hajný shares hard-won lessons from testing a Kiwi.com application with Jest and Testing Library – covering side-effect module mocking, partial mocks, async gotchas, and useful tooling.

8 min read
Inside Cookielab

European Coffee Trip releases mobile app for coffee lovers

The leading European specialty coffee guide launches its long-awaited iOS app – built by Cookielab.

3 min read
Software Development

Tackling recursion (not just) in TypeScript

Deep-diving into stack overflow risks with recursive functions in TypeScript and how trampolining solves them elegantly.

5 min read
Software Development

How to write your own JSON parser using functional TypeScript & fp-ts – part I

Building a fully functional JSON parser from scratch using fp-ts: defining parser types, composing parsers and combining them into sequences.

6 min read
Software Development

How to read config values from env using io-ts

A short guide to reading environment variables in a type-safe, functional way using io-ts – with human-readable error reporting.

3 min read
Software Development

Open Source @ Cookielab

Why we open-source our internal tools, how we decide what to share, and the projects we're most proud of.

3 min read
Software Development

Best Practices aka How not to be the worst developer

A practical checklist of habits every developer should adopt – from writing tests and doing proper code reviews to using linters and avoiding the any type.

6 min read
Software Development

Authentication: The Technological-Product View

Before picking an auth library, you need to answer dozens of product questions. This article walks through all of them.

7 min read

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