Senior iOS Engineer

Scope

You'll be building and improving a sophisticated memory curation platform that helps users discover their best moments, and create beautiful, personalised products automatically. The app intelligently curates photos from users' libraries, uses on-device ML for face recognition and photo analysis, and renders high-fidelity 3D previews of physical products. You'll work across features spanning photo selection, AI-assisted layout generation, payment processing, and immersive product visualisation.

About Popsa

Joining Popsa right now is pretty exciting. We’re a London-based, Certified B Corp building a memory curation platform that uses on-device intelligence and generative AI to help people find, organise, and relive the moments that matter, turning noisy photo libraries into curated stories with minimal effort and high confidence. 

We're also a proven, international growth business. Popsa was recognised in Deloitte's UK Technology Fast 50 (2022), making it our third year running on the list, and was also ranked the 19th fastest-growing software company that year. The Financial Times ranked Popsa as the 5th fastest-growing technology company in Europe and highly ranked in 2022, and in 2023 we retained our place in the FT 1000 for a second year, with an absolute growth rate of 1,000% over the measured period.

Our apps and service operate at global scale, localised across 12 languages, shipping to 50+ countries, with most orders placed from outside the UK.  More than 13 million people across 50 countries have used Popsa to turn their photos into something they can actually be proud to share. 

People have never taken more photos than they do today, but most of those memories end up buried in clutter. Popsa brings calm to that chaos, automatically surfacing meaningful moments, suggesting structure and themes, generating captions, and laying out designs, so anyone can create something beautiful without design skills.  From there, we make it easy to bring curated memories into the real world with premium photo products, including photo books, calendars, prints and photo boxes, delivered internationally. 

Private by design. We’re deliberate about what is processed on-device, what is uploaded, and how customer content is protected, so people can trust us with their most personal memories. 

Key responsibilities

Architecture & data

• Swift Package Manager for modular dependency management

• Protocol Buffers for efficient data serialisation with our backend

• Core Data for on-device persistence

• Repository pattern for clean data access abstractions

Concurrency & reactive programming

• Swift Structured Concurrency (async/await, actors)

• Combine for reactive data flows and UI bindings

Graphics & visualisation

• SceneKit and ARKit for immersive 3D product previews

• Custom Metal shaders for advanced rendering effects

• Vision and CoreML for on-device photo analysis and face recognition

Photo library integration

• Deep PhotoKit integration for accessing and analysing user photo libraries

• On-device ML models for face embeddings and photo quality scoring

• Smart album generation and photo metadata synchronisation

Third-party integrations

• Firebase (Analytics, Remote Config)

• Sentry for crash reporting and performance monitoring

• Stripe and Braintree for payment processing

• GrowthBook for feature flags and experimentation

• Nuke for high-performance image loading and caching

CI/CD & quality

• GitHub Actions for automated linting, testing, and snapshot testing

• Xcode Cloud for continuous integration

• Fastlane for release automation

• SwiftLint for code style consistency

• Snapshot testing for UI regression prevention

Version control & collaboration

• Git proficiency with trunk-based development

• Pull request workflows with thorough code reviews

Skills & experience

We’re primarily looking for recent experience developing high-quality, consumer-facing iOS apps where finesse, performance, and delight are priorities. 

• Strong experience developing production apps with Swift

• Deep understanding of UIKit architecture, with growing proficiency in SwiftUI for building modern UI components in a hybrid codebase

• Familiarity with the Coordinator pattern for managing complex navigation flows

• Experience with MVVM and protocol-oriented design

• Understanding of the iOS app lifecycle, including background tasks, widgets, and app extensions

• Proficiency handling resources, permissions, and responsive UI across device sizes

Nice to have

• Experience with custom drawing, Core Graphics, or advanced UI animations

• Performance optimisation and profiling with Instruments

• Accessibility best practices and VoiceOver support

• Experience integrating on-device ML models (CoreML, Vision)

• Background in 3D graphics or AR experiences

• Familiarity with localisation workflows for international apps

Personal attributes

• A problem-solving, curious, and inquisitive attitude

• Clear communicator with a keenness to work collaboratively

• Constructive approach to code reviews and architectural discussions