iOS Engineer - Platform

Wallapop is a Barcelona based scale-up driven by the purpose to empower people to embrace a more conscious and human way of consumption. We believe in a world where collaborative economy is mainstream. This is what drives us. 💫

Wallapop operates in Spain, Italy and Portugal, offering a catalogue of several hundreds of millions of products and services. Powered by technical innovation and continuous improvement, we bring together the scale & trust of classifieds with the marketplace’s convenience & reach. 🌱 Our mission is to enable a connected trade ecosystem, making 2nd-hand the norm through smart use of technology.

The Challenge 🧩

You will join the iOS Platform team, the team that sets the technical direction for iOS at Wallapop. Our users are primarily other engineers, and our mission is to supercharge their daily productivity while defending the quality and performance of our app. We own the build system, developer tooling, module architecture, testing infrastructure, and observability foundations that everyone else ships on top of.

We work on a 10+ year-old codebase used by millions of people (~115 modules and over 20,000 Swift files), where every second shaved off a build is multiplied across the entire engineering chapter.

In this role, you will own app performance as a product metric—from launch time and responsiveness to memory footprint and app size. As an iOS Platform Engineer, you will have company-wide scope, acting as an architect, mentoring engineers across the chapter, and tackling our most complex technical challenges.

Our tech stack:

• Build & Infra: Bazel-based build system with remote caching/execution, paired with Tente (our in-house Go CLI and BSP server to support IDEs like VSCode, Neovim).
• CI/CD & Testing: High-scale pipelines on Bitrise, a robust testing pyramid featuring Quick/Nimble, ~9,000 snapshot references, and Maestro E2E flows in the cloud.
• Architecture & UI: Simplified, TCA-inspired architecture built on RxSwift, custom dependency injection, UIKit, SwiftUI, and our Conchita design system.
• Observability & AI: Deep tracing via Sentry and OpenTelemetry, automated PR quality gates, and AI-assisted workflows (AI code-review bot and repo-native agents).

What You Will Do 👇

• Keep builds fast, hermetic, and understandable as the codebase and the team grow.
• Build developer tooling that engineers actually enjoy using, and measure whether it moves the needle on daily productivity.
• Maintain a healthy, fast, and trustworthy CI/CD and release pipeline, from PR checks to the App Store.
• Define, measure, and deliver on user-facing performance goals: app launch time, responsiveness, rendering smoothness, memory footprint, and crash-free rate.
• Profile with Instruments on real devices and optimize at the binary level (main-thread startup work, dyld and static initializers, binary layout, and framework count).
• Own the observability stack (Sentry/OpenTelemetry) to provide tracing and dashboards that engineers trust, and set up automated guardrails in CI to block regressions.
• Set the module boundaries and structural design of the app, leading migrations that cross a hundred modules without freezing feature delivery.
• Design and lead our structural architectural evolution, including the transition from RxSwift toward modern Swift Concurrency (async/await, actors, Sendable).
• Partner with feature teams as an enabler: unblock them, document the paths, and make "the right thing the easy thing" to do.
• Drive technical decisions with chapter-wide impact through RFCs and hands-on prototypes, aligning product, design, and backend stakeholders.
• Mentor iOS engineers across the company, raising the technical ceiling of the entire engineering chapter.

What We’re Looking For 🔎

• Extensive experience designing, developing, and scaling iOS applications in Swift.
• A proven track record of working in large, highly modular codebases, and comfort navigating and refactoring code you did not write.
• A platform mindset: treating other engineers as your users, measuring impact, and demonstrating a passion for developer experience.
• Deep, hands-on experience with mobile performance profiling (Instruments) and a strong understanding of what makes an app fast and stable.
• Strong autonomy and pragmatism, with the ability to scope massive technical migrations into safe, incremental, and highly strategic steps.
• Excellent communication and mentoring skills, with experience writing RFCs and guiding broader engineering chapters.
• Familiarity with AI coding assistants (e.g., Claude Code, GitHub Copilot) and using AI to enhance development workflows.

What Would Be A Plus 🚀

• Experience with Bazel (including remote caching/execution) or other non-Xcode build systems for Apple platforms.
• Deep ownership of mobile CI/CD pipelines, code signing, and release automation.
• Scripting beyond Swift (Go, Python, Ruby, shell) and a knack for writing custom CLIs.
• Experience with automated testing frameworks, snapshot testing, E2E frameworks, and flaky test triage at scale.
• Familiarity with AI coding assistants (e.g., Claude Code, GitHub Copilot) and adopting or developing harness engineering practices to make them reliable in a large codebase.
• Experience working on large-scale, high-traffic consumer applications.

Do note that all our jobs are 📍 Barcelona based. We follow a hybrid model where flexibility rules. We commit to a minimum of 6 days per month in the office. Each team self-organizes to decide on cadence and in-person/remote rituals.

Wallapop is an equal-opportunity employer. We celebrate diversity and are committed to creating an inclusive environment for all employees as we want Wallapop to be a place for everyone.

We sponsor visa processes for international candidates when applicable and provide legal & admin support along the process combined with a competitive relocation package.

Additionally to the opportunity to contribute to an agile product set up and work together towards achieving our meaningful mission, we offer the following 🍭 Perks & Benefits:

• Generous individual learning budget of 2k per year
• Free office meals, lunch selection from different providers
• Group and individual English, Catalan & Spanish lessons as part of our working day
• Private Health Insurance with Alan
• Flexible working hours + intensive Fridays
• Flexible remuneration to deduct from gross salary (kindergarten/food/transport check)
• Gym & Wellness plan, including physiotherapist in the office
• Generous referral Program & Charity Donation
• Bonus for weddings & newborns
• Wallapop Renta (Tax income support)
• Monthly plan for free shipping, bumps & home-pick-up on our services
• Work anniversary Gifts and Birthday Surprises
• Contribution towards your WIFI in your monthly payroll
• One-off payment based on compensation package to go towards setting up your home office
• Relocation package (monetary support and legal advice) and visa sponsorship, if applicable
• 26 holidays per year
• TOP hardware of your choice (latest Apple or Windows)

What does the hiring process for this position look like? 👀 **Please, note that all interviews take place remotely over hangouts.**

• Intro Call - run by Talent Acquisition, focus on providing more information about the role and the company as well as going over your experience, motivation, and expectations. This usually takes 45-60 minutes.
• Technical Task - you will be assigned a test that consists of a coding challenge to assess the technical skills required for the role. You will have up to 7 days to complete it. If you have a recent project that meets the same requirements, you can submit it instead.
• Expertise Interview - run by the core team, focusing on the hard skills and the ability to deliver in a given context. This usually takes 60-90 minutes.
• Stakeholder Interview - run by the hiring team and relevant stakeholders, focus on the ability to collaborate & deliver in a cross-functional set-up. This usually takes 60 minutes.
• Culture Interview - run by culture interviewers, focus on adherence to Wallapop's purpose and business proposition. This usually takes 60 minutes.
• Offer - should you be the right candidate, your offer will be discussed over a call with talent acquisition and will then be confirmed in writing.