Mikołaj Wilczek
@mikolaj.kiwicode.dev
I like mobile apps • React Native • Ionic
A local mobile backend won't start because port 3000 is busy? Select listeners:
kill $(lsof -t -iTCP:3000 -sTCP:LISTEN)
mikolajwilczek.dev/blog/lsof/?u...
kill $(lsof -t -iTCP:3000 -sTCP:LISTEN)
mikolajwilczek.dev/blog/lsof/?u...
Free a port with lsof and start a fresh server
Find and stop a local TCP listener with lsof, then start a fresh server. A quick fix for macOS and Linux.
mikolajwilczek.dev
September 24, 2026 at 2:15 PM
A local mobile backend won't start because port 3000 is busy? Select listeners:
kill $(lsof -t -iTCP:3000 -sTCP:LISTEN)
mikolajwilczek.dev/blog/lsof/?u...
kill $(lsof -t -iTCP:3000 -sTCP:LISTEN)
mikolajwilczek.dev/blog/lsof/?u...
Reposted by Mikołaj Wilczek
Am I seeing this right? Right next to the surprising Xcode change from .pbxproj (XML) to .xcproj (JSON), are we also getting a library for working with the new Xcode project format github.com/apple/xcode-...?
GitHub - apple/xcode-project-format: A Swift library for reading, writing, and manipulating Xcode's JSON-based project.xcproj format.
A Swift library for reading, writing, and manipulating Xcode's JSON-based project.xcproj format. - apple/xcode-project-format
github.com
September 18, 2026 at 6:13 PM
Am I seeing this right? Right next to the surprising Xcode change from .pbxproj (XML) to .xcproj (JSON), are we also getting a library for working with the new Xcode project format github.com/apple/xcode-...?
`sdkmanager` and `avdmanager` provision an AVD. `emulator` boots it. `adb`
installs the app and collects diagnostics. I reuse these commands in repeatable
scripts and AI skills.
A Google APIs image gave me root/remount access.
How do you use them?
mikolajwilczek.dev/blog/android...
installs the app and collects diagnostics. I reuse these commands in repeatable
scripts and AI skills.
A Google APIs image gave me root/remount access.
How do you use them?
mikolajwilczek.dev/blog/android...
Where Android Emulator fits in a robust Capacitor development loop
Use web previews, a scriptable Android Emulator, and physical phones as complementary feedback layers in a reliable Capacitor development loop.
mikolajwilczek.dev
September 4, 2026 at 9:34 AM
`sdkmanager` and `avdmanager` provision an AVD. `emulator` boots it. `adb`
installs the app and collects diagnostics. I reuse these commands in repeatable
scripts and AI skills.
A Google APIs image gave me root/remount access.
How do you use them?
mikolajwilczek.dev/blog/android...
installs the app and collects diagnostics. I reuse these commands in repeatable
scripts and AI skills.
A Google APIs image gave me root/remount access.
How do you use them?
mikolajwilczek.dev/blog/android...
Ask what people have done instead of whether an idea sounds good.
The Mom Test uses this in startup conversations. I think the same questions are useful for feature decisions in established products and for personal feedback.
www.momtestbook.com
The Mom Test uses this in startup conversations. I think the same questions are useful for feature decisions in established products and for personal feedback.
www.momtestbook.com
The Mom Test by Rob Fitzpatrick
How to talk to customers & learn if your business is a good idea when everyone is lying to you.
www.momtestbook.com
August 26, 2026 at 2:17 PM
Ask what people have done instead of whether an idea sounds good.
The Mom Test uses this in startup conversations. I think the same questions are useful for feature decisions in established products and for personal feedback.
www.momtestbook.com
The Mom Test uses this in startup conversations. I think the same questions are useful for feature decisions in established products and for personal feedback.
www.momtestbook.com
A fresh laptop reveals the Node, Ruby, Java, and CLI versions that a project
forgot to record.
asdf and mise manage those versions from a file in the repository. The file
documents one setup path for the team.
mikolajwilczek.dev/blog/boring-...
forgot to record.
asdf and mise manage those versions from a file in the repository. The file
documents one setup path for the team.
mikolajwilczek.dev/blog/boring-...
Make SDK management boring with asdf and mise
Manage Node, Ruby, Java, and project-specific CLIs with repository-owned versions, then decide when nvm, asdf, or mise fits.
mikolajwilczek.dev
August 19, 2026 at 6:02 PM
A fresh laptop reveals the Node, Ruby, Java, and CLI versions that a project
forgot to record.
asdf and mise manage those versions from a file in the repository. The file
documents one setup path for the team.
mikolajwilczek.dev/blog/boring-...
forgot to record.
asdf and mise manage those versions from a file in the repository. The file
documents one setup path for the team.
mikolajwilczek.dev/blog/boring-...
Need a quick HTTPS endpoint? `openssl s_server -www` serves a status page and
shows handshakes, separating connectivity from TLS problems.
mikolajwilczek.dev/blog/openssl...
shows handshakes, separating connectivity from TLS problems.
mikolajwilczek.dev/blog/openssl...
TIL: OpenSSL can serve HTTPS
Use OpenSSL's built-in test server to run a temporary HTTPS endpoint while debugging TLS.
mikolajwilczek.dev
August 5, 2026 at 6:00 PM
Need a quick HTTPS endpoint? `openssl s_server -www` serves a status page and
shows handshakes, separating connectivity from TLS problems.
mikolajwilczek.dev/blog/openssl...
shows handshakes, separating connectivity from TLS problems.
mikolajwilczek.dev/blog/openssl...
😄 I’m adopting a new ticket status between In Progress and Review:
👀 Reading
👀 Reading
July 22, 2026 at 9:01 AM
😄 I’m adopting a new ticket status between In Progress and Review:
👀 Reading
👀 Reading
.mobileconfig packaged a root CA but didn’t grant trust: two iPhones still needed Full Trust manually. A useful boundary for dev tooling.
mikolajwilczek.dev/blog/mobilec...
mikolajwilczek.dev/blog/mobilec...
Are .mobileconfig profiles useful for iOS developers?
A developer-focused look at iOS .mobileconfig profiles: what they configure, why a profile containing only a root CA added no value, and when to use one.
mikolajwilczek.dev
July 21, 2026 at 5:41 PM
.mobileconfig packaged a root CA but didn’t grant trust: two iPhones still needed Full Trust manually. A useful boundary for dev tooling.
mikolajwilczek.dev/blog/mobilec...
mikolajwilczek.dev/blog/mobilec...
TIL: iOS simulator can trust a root CA from the CLI: xcrun simctl keychain booted add-root-cert
More detailed note: mikolajwilczek.dev/blog/add-roo...
More detailed note: mikolajwilczek.dev/blog/add-roo...
Add iOS Simulator root cert with simctl
Add a local root CA to iOS Simulator for HTTPS dev servers, Capacitor live reload, and proxy debugging.
mikolajwilczek.dev
July 8, 2026 at 2:05 PM
TIL: iOS simulator can trust a root CA from the CLI: xcrun simctl keychain booted add-root-cert
More detailed note: mikolajwilczek.dev/blog/add-roo...
More detailed note: mikolajwilczek.dev/blog/add-roo...
Reposted by Mikołaj Wilczek
Missed unapplied method refs for Swift actors? 😩
Good news: the fix is already merged on main in Swift’s repo. Waiting for its version debut ⏳
Itchy to catch up? This infographic summarizes the bug, isolation context, and unapplied method refs + more on the blog -> blog.kiwicode.dev/posts/unappl...!
Good news: the fix is already merged on main in Swift’s repo. Waiting for its version debut ⏳
Itchy to catch up? This infographic summarizes the bug, isolation context, and unapplied method refs + more on the blog -> blog.kiwicode.dev/posts/unappl...!
March 2, 2026 at 5:04 PM
Missed unapplied method refs for Swift actors? 😩
Good news: the fix is already merged on main in Swift’s repo. Waiting for its version debut ⏳
Itchy to catch up? This infographic summarizes the bug, isolation context, and unapplied method refs + more on the blog -> blog.kiwicode.dev/posts/unappl...!
Good news: the fix is already merged on main in Swift’s repo. Waiting for its version debut ⏳
Itchy to catch up? This infographic summarizes the bug, isolation context, and unapplied method refs + more on the blog -> blog.kiwicode.dev/posts/unappl...!
Reposted by Mikołaj Wilczek
I wrote a short visual explainer on Swift SE-0518 (~Sendable): what it means, where it fits, and a few practical gotchas. Plus a bonus question the syntax naturally brings up: should everything really be Sendable by default? Check it here: blog.kiwicode.dev/posts/sendab...
March 23, 2026 at 6:04 PM
I wrote a short visual explainer on Swift SE-0518 (~Sendable): what it means, where it fits, and a few practical gotchas. Plus a bonus question the syntax naturally brings up: should everything really be Sendable by default? Check it here: blog.kiwicode.dev/posts/sendab...
Reposted by Mikołaj Wilczek
📣Announcing the first preview releases of Swift for Android, enabling you to build Android business logic with the same Swift that you use for Apple platforms. www.swift.org/blog/nightly... #Android
October 24, 2025 at 8:06 PM
📣Announcing the first preview releases of Swift for Android, enabling you to build Android business logic with the same Swift that you use for Apple platforms. www.swift.org/blog/nightly... #Android
Reposted by Mikołaj Wilczek
Curious about building your own #Bluesky feed? 🛠️ This #TIL #blog post blog.michal.pawlik.dev/posts/bluesk... will walk you through the process.
I'm no bsky expert, I just learned that while making the #Scala feed bsky.app/profile/mich...
I'm no bsky expert, I just learned that while making the #Scala feed bsky.app/profile/mich...
Your own Bluesky feed - Dev notes
In this post we’ll learn how to build and deploy your own feed on Bluesky. We’ll start with some background info on Bluesky and how feeds work. Then we’ll code and deploy our own feed. Don’t worry abo...
blog.michal.pawlik.dev
November 27, 2024 at 10:11 PM
Curious about building your own #Bluesky feed? 🛠️ This #TIL #blog post blog.michal.pawlik.dev/posts/bluesk... will walk you through the process.
I'm no bsky expert, I just learned that while making the #Scala feed bsky.app/profile/mich...
I'm no bsky expert, I just learned that while making the #Scala feed bsky.app/profile/mich...