Why personal iPhone apps are finally worth building
Xcode has allowed development installs for years. AI changed how much work it takes to get a tested native app onto your phone.
VelvetShark • Radek Sienkiewicz
Radek's personal website about learnings, challenges, software development, and much more.
Latest posts
One bored voice: how I rebuilt the Polish lektor with the technology he inspired
Poland never dubbed films with a cast of actors. One man read every line, flat and unbothered, over the quieted original. ElevenLabs exists partly because its founders grew up with that voice. So I rebuilt him with their own technology: a site where any video comes back with a deadpan Polish lektor. This is how it works, including the timing algorithm that turned out to be the actual craft.
OpenClaw Memory Masterclass: The complete guide to agent memory that survives
Your OpenClaw agent works great for 20 minutes, then silently loses its instructions. The root cause is compaction, and most users don't understand it. This guide explains the full memory lifecycle and gives you a file architecture that prevents the forgetting.
50 days with OpenClaw: The hype, the reality and what actually broke
Most OpenClaw content right now is first-week impressions or setup tutorials. Nobody can tell you what happens after the first month because they haven't been there yet. I have. Every single day for 50+ days. Here are 20 real workflows I use daily, what broke along the way, and my honest assessment of whether it's worth your time.
Stop overpaying for OpenClaw: Multi-model routing guide
If you're running OpenClaw, there's a good chance you're burning money without realizing it. By default, everything goes to your primary model - heartbeats, sub-agents, simple queries. This guide shows you how to cut costs by 50-80% with one config change, without losing quality on the tasks that actually matter.
Compound Engineering: the AI coding workflow that actually learns
Most developers use AI to code faster today, but they're missing the bigger opportunity. Compound Engineering is a workflow where every code review teaches the system something new, every bug fix becomes a rule it won't break again, and the knowledge compounds over time.
Data analysis with Claude Code: 500,000 rows without writing code
Go from a raw Excel file with half a million rows to a finished report with KPIs, charts, and cohort analysis - step by step, with real prompts you can copy.
ClawdBot: The self-hosted AI that Siri should have been
A personal AI assistant that runs on a $5/month server, lives in your messaging apps, remembers everything, and actually reaches out to help you. Here's how to set it up.
Stop prompting Claude Code - let it interview you
The spec workflow that went viral: instead of telling Claude what to build, you let Claude interview you first. Here's how it works, when to use it, and how to turn it into a one-command shortcut.
Building a Large Language Model from scratch: A learning journey
A daily learning journey of learning how to build a large language model from scratch. Understanding transformers, attention mechanisms, GPT architecture, training process. Documenting insights, concepts and implementations as I learn how LLMs actually work under the hood.
Banana Straightener: AI image generation that actually gets it right
Finally, an AI image generator that doesn't give up after one try. Because your creative vision deserves better than digital dice rolls.
Why do AI company logos look like buttholes?
A humorous exploration of the uncanny resemblance between AI company logos and human anatomy. Discover why circular, gradient-based designs dominate the AI industry, and what this design convergence tells us about branding in tech.
My AI agents journey
My month-long exploration of AI agents, where I built practical solutions from simple chatbots to email automation. Learn when to use AI versus traditional automation, and follow my recommended learning path for AI development beginners.
12 challenges in 12 months. Again.
After a transformative year of monthly challenges in 2021, I'm embarking on a new set of 12 challenges for 2025 - from AI agents and sleep optimization to breathwork and niche expertise. Join me on this journey of personal growth and experimentation.
SummerIce: A Simple solution for information overload
A free Chrome extension that allows you to quickly and easily summarize articles on any website, with one click or one keyboard shortcut, you'll get a concise summary in just a few seconds.
EIP-3074 - Pass the AUTH, please!
EIP-3074: a transformative Ethereum proposal introducing new opcodes that enable externally owned accounts (EOAs) to delegate transaction capabilities to smart contracts. This enables transaction batching, sponsored transactions, and social recovery.
ERC-1271 - Now smart contracts can sign transactions too!
ERC-1271 enables smart contracts to verify signatures, allowing them to sign transactions. Learn why it's crucial for smart contract wallets and the use cases it unlocks.
ERC-4337 - It's all about Account Abstraction
ERC-4337 brings account abstraction to Ethereum, enabling smart contract wallets, ERC20 gas fees, and improved UX without sacrificing decentralization.
What are Ethereum Standards - EIPs, ERCs, RIPs, CAIPs
Discover the four main types of blockchain standards—EIPs, ERCs, RIPs, and CAIPs—in this detailed guide. Learn how these standards enhance Ethereum protocol usability and interoperability across multiple blockchains.
How many time zones are there in the world?
There's a popular misconception that there are 24 time zones in the world. Nope, there are more.
Solidity Smart Contract Template
A cheetsheet for a Solidity contract layout and structure, to know what goes where and how.
Merkle Trees
How to understand Merkle trees, write and test your smart contract, together with Solidity exercises
Pushing my limits - What I learned from a year of monthly challenges
What I learned from doing 12 challenges in 12 months, and how it changed my life.
December Challenge: Daily post on Instagram
December Challenge summary: Daily post on Instagram. What I learned from it, how it went, and will I keep doing it?
How to Become a Crypto Billionaire in 15 Minutes. Legally.
How I became a billionaire in 15 minutes. True story. With proof of all of the transactions.
Consistency
I'm lazy. But also I'm extremely consistent at the tasks that I do. This is the system I came up with to get consistent and to work around my laziness.
November Challenge: No coffee
November Challenge summary: No coffee. What I learned from it, how it went, and will I keep doing it?
October Challenge: 7-minute daily hanging
October Challenge summary: Hanging 7 minutes a day, in total. What I learned from it, how it went, and will I keep doing it?
Max values for each uint in Solidity, from uint8 to uint256
Max values for each uint in Solidity, from uint8 to uint256.
September Challenge: One hour of learning every day
September Challenge summary: One hour of learning every day. What I learned from it, how it went, and will I keep doing it?
Don't do stupid shit
The formula and explanation of how not to do stupid shit and what to do instead.
August Challenge: No alcohol
August Challenge summary: No alcohol. What I learned from it, how it went, and will I keep doing it?
My 200 days of daily web3 learning and building
A detailed journey of 200 days of learning web3: what worked, what didn't, what I built, what I learned, highlights, downsides, resources, what's next.
July Challenge: Cold shower in the morning
July Challenge summary: Cold shower in the morning. What I learned from it, how it went, and will I keep doing it?
June Challenge: Waking up before 9 AM
June Challenge summary: Waking up before 9 AM. How it went, what I learned from it, will I keep doing it?
May Challenge: 30 minutes of reading a paper book
May Challenge summary: 30 minutes of reading a paper book. How it went, what I learned from it, will I keep doing it?
Web3 Learning Journey month 2 update: it's all starting to come together
Month 2 summary of learning web3 development.
April Challenge: No sugar (again)
April Challenge summary: zero sugar. How it went, what I learned from it, will I keep doing it?
Web3 Learning Journey 1-month update: React and starting with Solidity
Month 1 summary of learning crypto development. React basics and starting with Solidity.
My web3 Learning Journey
I'm learning web3 and sharing my learnings in public.
My new best friend
I was stuck with a toxic friend and a stranger. I've replaced them with two great guys.
March Challenge: The effects of zero sugar and zero news
March Challenge summary: zero sugar, zero news. How it went, what I learned from it, will I keep doing it?
February Challenge results: The effects of publishing daily for a month
February Challenge summary: Daily publishing. How it went, what I learned from it, will I keep doing it?
January Challenge results: Great effort, great outcome, needs modifying
January Challenge summary: what it was, how it went, what I learned from it, will I keep doing it?
What happens when your article is mentioned in the Morning Brew newsletter?
What happens (and what doesn't happen) when your article is mentioned in the newsletter that goes out to 2m+ people.
How to develop a bias for action
A compilation of research, findings, and my own experience on developing a bias for action.
A Challenging Year with twelve 30-day challenges
Twelve monthly challenges, one for each month in 2021. Zero sugar, 50 push-ups per day, doing only "boring" stuff for a month, and everything in between.
Why do so many brands change their logos and look like everyone else?
Tech and fashion logos are becoming increasingly similar, all of them using sans serif fonts. Why do they do that? And why it doesn't make sense.
To get food, I learned Selenium and web scraping in one day. And I’m not even a programmer.
I couldn't buy groceries online because the waiting time for delivery was 2 months. I decided to automate the process of checking if any deliver slot opens up and then instantly booking it. I had to learn Selenium to do this. I succeeded.
How to read large files on a Mac (CSV, JSON, etc.)
Opening text files, even the big ones, should be easy. Even huge ones. It's just text after all. Turns out, it's surprisingly difficult and I had to dig to find out a good way to do it.