Alex Ozun
@alexozun.com
Staff iOS Engineer | https://swiftology.io
Based in 🇬🇧 Born in 🇺🇦 All opinions are my own
Based in 🇬🇧 Born in 🇺🇦 All opinions are my own
Pinned
Alex Ozun
@alexozun.com
· 5d
GitHub - Alex-Ozun/swift-effect: Algebraic Effects and Effect Handlers for Swift
Algebraic Effects and Effect Handlers for Swift. Contribute to Alex-Ozun/swift-effect development by creating an account on GitHub.
github.com
Swift Effect is now in public preview! it is an architecture-agnostic effect system that makes side effects (such as I/O, networking, randomness, concurrency) controllable, composable, and testable without forcing structural changes to your application code.
github.com/Alex-Ozun/sw...
#swiftlang
github.com/Alex-Ozun/sw...
#swiftlang
The library also enables deterministic testing of unstructured Swift Concurrency.
If you're interested, please give the project description a read and share your feedback and ideas.
#swiftlang
If you're interested, please give the project description a read and share your feedback and ideas.
#swiftlang
January 5, 2026 at 1:26 PM
The library also enables deterministic testing of unstructured Swift Concurrency.
If you're interested, please give the project description a read and share your feedback and ideas.
#swiftlang
If you're interested, please give the project description a read and share your feedback and ideas.
#swiftlang
In tests, the same mechanism powers *mock-less* testing of behaviours: observable effects can be intercepted, suspended, and resumed with just-in-time test data, without invasive scaffolding or test-only abstractions in application code, commonly required by DI libs and arch frameworks.
#swiftlang
#swiftlang
January 5, 2026 at 1:26 PM
In tests, the same mechanism powers *mock-less* testing of behaviours: observable effects can be intercepted, suspended, and resumed with just-in-time test data, without invasive scaffolding or test-only abstractions in application code, commonly required by DI libs and arch frameworks.
#swiftlang
#swiftlang
With just two lightweight abstractions, Effects and Effect Handlers, it enables natural composition of behaviours while keeping application code linear, procedural, and easy to reason about.
#swiftlang
#swiftlang
January 5, 2026 at 1:26 PM
With just two lightweight abstractions, Effects and Effect Handlers, it enables natural composition of behaviours while keeping application code linear, procedural, and easy to reason about.
#swiftlang
#swiftlang
Swift Effect is now in public preview! it is an architecture-agnostic effect system that makes side effects (such as I/O, networking, randomness, concurrency) controllable, composable, and testable without forcing structural changes to your application code.
github.com/Alex-Ozun/sw...
#swiftlang
github.com/Alex-Ozun/sw...
#swiftlang
GitHub - Alex-Ozun/swift-effect: Algebraic Effects and Effect Handlers for Swift
Algebraic Effects and Effect Handlers for Swift. Contribute to Alex-Ozun/swift-effect development by creating an account on GitHub.
github.com
January 5, 2026 at 1:26 PM
Swift Effect is now in public preview! it is an architecture-agnostic effect system that makes side effects (such as I/O, networking, randomness, concurrency) controllable, composable, and testable without forcing structural changes to your application code.
github.com/Alex-Ozun/sw...
#swiftlang
github.com/Alex-Ozun/sw...
#swiftlang
In tests, the same mechanism powers *mock-less* testing of behaviours: observable effects can be intercepted, suspended, and resumed with just-in-time test data, without invasive scaffolding or test-only abstractions in application code, commonly required by DI libs and architectural frameworks.
January 5, 2026 at 1:23 PM
In tests, the same mechanism powers *mock-less* testing of behaviours: observable effects can be intercepted, suspended, and resumed with just-in-time test data, without invasive scaffolding or test-only abstractions in application code, commonly required by DI libs and architectural frameworks.
With just two lightweight abstractions, Effects and Effect Handlers, it enables natural composition of behaviours while keeping application code linear, procedural, and easy to reason about.
January 5, 2026 at 1:23 PM
With just two lightweight abstractions, Effects and Effect Handlers, it enables natural composition of behaviours while keeping application code linear, procedural, and easy to reason about.
Hey friend, I've got a new article on Swift Testing for you! 📝
I share my insights on avoiding common pitfalls of Parameterized Tests, gained from overseeing the migration of tens of thousands of tests from XCTest to Swift Testing.
swiftology.io/articles/pit...
#swiftlang #swift
I share my insights on avoiding common pitfalls of Parameterized Tests, gained from overseeing the migration of tens of thousands of tests from XCTest to Swift Testing.
swiftology.io/articles/pit...
#swiftlang #swift
Pitfalls of Parameterized Tests | Swiftology
In this article, I share my experience adopting Swift Testing at scale and the lessons I learned about **Parameterized Tests**, including five common pitfalls teams may encounter. I also recommend bes...
swiftology.io
November 11, 2025 at 3:33 PM
Hey friend, I've got a new article on Swift Testing for you! 📝
I share my insights on avoiding common pitfalls of Parameterized Tests, gained from overseeing the migration of tens of thousands of tests from XCTest to Swift Testing.
swiftology.io/articles/pit...
#swiftlang #swift
I share my insights on avoiding common pitfalls of Parameterized Tests, gained from overseeing the migration of tens of thousands of tests from XCTest to Swift Testing.
swiftology.io/articles/pit...
#swiftlang #swift
Hey look what just dropped! A recording of my recent talk from iOSKonf25!
The recording didn't capture the stage camera's feed, but that's totally fine because I have a radio face anyway 🫥
youtu.be/AnUS_zmSnVg
#swiftlang #swiftui #ios
The recording didn't capture the stage camera's feed, but that's totally fine because I have a radio face anyway 🫥
youtu.be/AnUS_zmSnVg
#swiftlang #swiftui #ios
Make Invalid States Impossible in Your App | iOSKonf25 | Alex Ozun
YouTube video by iOSKonf
youtu.be
October 22, 2025 at 2:24 PM
Hey look what just dropped! A recording of my recent talk from iOSKonf25!
The recording didn't capture the stage camera's feed, but that's totally fine because I have a radio face anyway 🫥
youtu.be/AnUS_zmSnVg
#swiftlang #swiftui #ios
The recording didn't capture the stage camera's feed, but that's totally fine because I have a radio face anyway 🫥
youtu.be/AnUS_zmSnVg
#swiftlang #swiftui #ios
Reposted by Alex Ozun
Finally got around to watching @alexozun.com‘s talk here. Truly fascinating stuff, and I learned something about non-Copyable types too!
youtu.be/qPHjDlqHsUQ?...
youtu.be/qPHjDlqHsUQ?...
Typestate - the new Design Pattern in Swift 5.9 | Swift Heroes 2024 Talk
YouTube video by Swift Heroes
youtu.be
June 13, 2025 at 10:54 PM
Finally got around to watching @alexozun.com‘s talk here. Truly fascinating stuff, and I learned something about non-Copyable types too!
youtu.be/qPHjDlqHsUQ?...
youtu.be/qPHjDlqHsUQ?...
Reposted by Alex Ozun
This is the second time I’ve seen @alexozun.com’s talk on making invalid state impossible and it’s a really cool approach to improved software safety!
May 20, 2025 at 3:33 PM
This is the second time I’ve seen @alexozun.com’s talk on making invalid state impossible and it’s a really cool approach to improved software safety!
How smooth is your learning curve?
May 20, 2025 at 1:45 PM
How smooth is your learning curve?
Doug Gregor takes the stage of @swiftcraft.bsky.social with a keynote talk On Progressive Disclosure in #swiftlang
May 20, 2025 at 1:45 PM
Doug Gregor takes the stage of @swiftcraft.bsky.social with a keynote talk On Progressive Disclosure in #swiftlang
I had a blast presenting at #iOSKonf25 this week! I heard great things about this conference and I now can say that the praise was well-deserved!
It was pretty scary to be on the lineup with so many accomplished engineers and speakers, but the vibe was really good and everyone was easy to be around.
It was pretty scary to be on the lineup with so many accomplished engineers and speakers, but the vibe was really good and everyone was easy to be around.
May 16, 2025 at 12:26 PM
I had a blast presenting at #iOSKonf25 this week! I heard great things about this conference and I now can say that the praise was well-deserved!
It was pretty scary to be on the lineup with so many accomplished engineers and speakers, but the vibe was really good and everyone was easy to be around.
It was pretty scary to be on the lineup with so many accomplished engineers and speakers, but the vibe was really good and everyone was easy to be around.
Reposted by Alex Ozun
Next up: @alexozun.com on how to make invalid states impossible in your app.
May 14, 2025 at 7:50 AM
Next up: @alexozun.com on how to make invalid states impossible in your app.
Same with dictionaries.
[Key: Value] or [Key : Value]
[Key: Value] or [Key : Value]
April 26, 2025 at 7:11 AM
Same with dictionaries.
[Key: Value] or [Key : Value]
[Key: Value] or [Key : Value]
Thanks! I'll share the recording when it's published on YouTube
April 10, 2025 at 9:57 AM
Thanks! I'll share the recording when it's published on YouTube
Thank you Peter! And thanks again for borrowing your clicker (I'd already added it to my Bday wish list 😀)
April 10, 2025 at 7:08 AM
Thank you Peter! And thanks again for borrowing your clicker (I'd already added it to my Bday wish list 😀)
I think I managed to successfully trick the audience into thinking we were simply describing effects with enums, until finally revealing that we’d actually learned something that *supposedly* requires a PhD in Computer Science to understand (spoiler: it really doesn’t!).
April 10, 2025 at 6:09 AM
I think I managed to successfully trick the audience into thinking we were simply describing effects with enums, until finally revealing that we’d actually learned something that *supposedly* requires a PhD in Computer Science to understand (spoiler: it really doesn’t!).
The secret to introducing people to scary-sounding concepts like Free Monads in #swiftlang is in never mentioning these two words until the very end of the presentation.
April 10, 2025 at 6:07 AM
The secret to introducing people to scary-sounding concepts like Free Monads in #swiftlang is in never mentioning these two words until the very end of the presentation.
Tiers of Swift development sins by Pietro Messineo at @swiftheroes.bsky.social
April 8, 2025 at 3:57 PM
Tiers of Swift development sins by Pietro Messineo at @swiftheroes.bsky.social
Haha, thank you Oliver 🙌 see you next week in Turin!
April 4, 2025 at 8:09 PM
Haha, thank you Oliver 🙌 see you next week in Turin!
I am, of course, just bastardising the
en.m.wikipedia.org/wiki/Fundame...
en.m.wikipedia.org/wiki/Fundame...
Fundamental theorem of software engineering - Wikipedia
en.m.wikipedia.org
March 27, 2025 at 10:37 AM
I am, of course, just bastardising the
en.m.wikipedia.org/wiki/Fundame...
en.m.wikipedia.org/wiki/Fundame...