Roy Marmelstein - Staff Engineer

Roy Marmelstein

Staff Engineer - IOS at Spotify

Stockholm, Stockholm County, Sweden

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Summary

🤩

Rockstar

🎓

Top School

Roy Marmelstein is a Staff iOS Engineer based in Stockholm with a decade of experience building polished, performance-conscious mobile apps and frameworks. Currently at Spotify, he blends deep Swift expertise with a history of shipping reusable libraries—authoring popular open-source projects for interpolation-driven animations, phone number parsing, zipping utilities, and localization—that reflect a strong focus on developer-friendly APIs. He’s comfortable across low-level integration (minizip support, password-protected archives) and high-level UX features (peek/pop, gesture-driven animations), and has contributed to large-scale frameworks like AsyncDisplayKit and Spotify’s HubFramework. A former Senior iOS Engineer at Zenly and long-time freelance developer, Roy balances product-focused iteration with careful testing and sample apps to make adoption straightforward. Fun fact: his GitHub work shows a habit of improving ergonomics—adding sample apps, file browsers, and easy APIs—to turn technical libraries into practical tools for other engineers.

11 years of coding experience

6 years of employment as a software developer

Brighton College

BSc Hons, Accounting and Finance, BSc Hons, Accounting and Finance at University of Warwick

English, French, Hebrew

Github Skills (34)

unit-testing10

uitextview10

objective-c10

file-management10

ios10

mobile-development10

internationalization10

interpolation10

ui-design10

zip10

data-structure10

asyncdisplaykit10

mobile-application10

regular-expression10

uid10

Programming languages (8)

C++CObjective-C++JavaScriptObjective-CSwiftSlimRuby

Github contributions (5)

marmelroy/Localize-Swift

Aug 2015 - Sep 2020

Swift friendly localization and i18n with in-app language switching

Role in this project:

Localization / Internationalization Specialist

Contributions:14 releases, 169 commits, 24 PRs in 5 years 2 months

Contributions summary:Roy primarily focused on the implementation and improvement of localization features within the `localize-swift` repository. Their contributions included initial setup of the localization functionality, removing and fixing errors in the original implementation, and improving and extending the syntax for localization. The user added support for the Swift 2 syntax and improved the example language switcher. The user also added the ability to specify the table name and bundle name for the localized strings.

language-switchinglocalizationswift

marmelroy/Interpolate

Mar 2016 - Jan 2021

Swift interpolation for gesture-driven animations

Role in this project:

Mobile Developer (iOS)

Contributions:11 releases, 99 commits, 11 PRs in 4 years 10 months

Contributions summary:Roy appears to be primarily responsible for developing the core functionality of the iOS application. The user started with an initial setup of the test suite. They focused on implementing a Swift interpolation framework. The user then improved the API and added a sample application with view controller elements to test the interpolation functionality. Finally, the user worked on improvements to the API to support UI elements like colors.

swiftinterpolationgesture-recognizergesture-driven-animationsanimation

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