Principal Design Engineer, Mobile (iOS)

Leadout Capital; San Francisco (CA); On-site; USD 180,000 - 260,000; Full time

Job summary

Slack is seeking a Principal Design Engineer to elevate the craft of our iOS experience. You will prototype directly in code to test nascent concepts, focusing on device capabilities and platform-native patterns.

You’ll shape how designers work in production iOS codebases and evangelize agentic prototyping practices across teams. You will lead by example with 8+ years at the intersection of product design and iOS engineering, delivering real prototypes that tie to customer love and business

Qualifications

• 8+ years at the intersection of product design and iOS engineering with hands-on Swift/SwiftUI and Objective-C.
• Track record of building real, working prototypes in code that directly impacted customer experience.
• Deep knowledge of iOS platform standards (Apple HIG, native frameworks) and judgment to pursue bespoke solutions when needed.
• Experience creating tools, documentation, or training to help other designers and engineers elevate their craft.

Responsibilities

• Prototype nascent interaction concepts directly in code to validate viability before full implementation.
• Expand iOS platform mastery within the team and document agentic workflows for designers to prototype in mobile codebases.
• Collaborate with designers and engineers to bring technical and craft expertise to ongoing projects.
• Coach and mentor peers to elevate production iOS prototyping practices across the org.

Skills

Swift/SwiftUI

Objective-C

Code prototyping

Mobile design craft

Tools

WidgetKit

App Intents

Live Activities

Shortcuts

Apple HIG

Job description

The Experience

We're hiring a Principal Design Engineer to elevate the craft and explore what's possible within Slack's iOS experience. Slack is an app that is used by millions of people every day as a core part of getting their work done. This role sits at the intersection of design and engineering: you'll rapidly prototype directly in code to bring real life to nascent, half-formed concepts that need both technical and craft judgment to assess their viability and their ability to make what we ship better. We'd love to find someone who not only is excited about this opportunity, but the unique modalities and possibilities of mobile experiences and how they can overlap and meaningfully differentiate from their desktop counterparts. We want someone who is an evangelist at heart and will thrive with the charter to elevate the design team's awareness and abilities by bringing modern, agentic prototyping practices into how designers work in production iOS codebases. We appreciate designers who think deeply, speak clearly, love collaboration and feedback, and have an excellent collection of animated gifs. At Slack, we have a positive, diverse, and encouraging culture. We look for people who are curious, inventive, and work to be a little better every single day!

What You'll Actually Be Doing

• Exploring nascent, ambiguous interaction and device capability concepts by prototyping directly in code, bringing both technical depth and design craft to ideas before they're fully considered. Turning "what ifs" into something people can feel and react to with tangible experiences in their hand.
• Building a deep, current understanding of iOS platform capabilities (WidgetKit, App Intents, Live Activities, Shortcuts, etc.), rooting solutions in platform-native standards and interaction patterns by default. Knowing when and how to break from them to build something genuinely bespoke.
• Acting as a skill multiplier for the broader design org. Conducting training and documenting agentic prototyping workflows so designers themselves can prototype directly in mobile codebases, not just hand off static specs.
• Partnering with designers and engineers across the org to inject technical and craft expertise wherever it's needed most. Coming to provide direct solutions for various team's current work, or providing creative / technical guidance around native solutions or custom approaches

You're Our Person If...

• 8+ years at the intersection of product design and iOS engineering, with deep hands‑on fluency in Swift/SwiftUI and Objective-C
• A track record of building real, working prototypes in code to explore ambiguous concepts. Ideally showing how their execution had a direct correlation to impact and customer love
• Deep, current knowledge of iOS platform standards and capabilities (Apple HIG, native frameworks), paired with the judgment to know when a bespoke, non-standard solution is worth building.
• Experience creating tools, documentation, or training that help other designers and engineers level up their own craft, embodying a multiplier mindset over a "my feature" mindset.