(Senior) Mobile Engineer (d/f/m) - iOS & Android

paymenttools; Köln; Sur place; EUR 90 000 - 120 000; Plein temps

Avantages offerts par ce poste

Deutschland ticket

1,000 euro learning & development

REWE discount card

Dienstrad bicycle leasing

Corporate benefits discounts

Insurance services

Résumé du poste

Paymenttools is seeking a (Senior) Mobile Engineer with extensive iOS proficiency and practical Android experience. You will own the iOS side of the WhiteLabelPay SDK and related mobile products, ensuring API stability, backward compatibility, and a seamless developer experience across platforms.

You will work closely with product, engineering, and customers, shaping SDKs and mobile interfaces for millions of users while embracing secure, cloud-native practices.

Qualifications

• Several years of professional mobile engineering experience.
• Strong iOS development experience with Swift and the Apple framework ecosystem.
• Practical Android experience with Kotlin and cross-platform collaboration.
• Experience building or maintaining SDKs or developer-facing components.
• Fluent English; German skills are a plus.

Responsabilités

• Own, develop, and evolve the iOS implementation of the WhiteLabelPay SDK.
• Design stable APIs for easy integration and minimal misuse.
• Coordinate iOS and Android to ensure consistent behavior and contracts.
• Contribute to Android architecture using Kotlin and cross‑platform awareness.
• Improve developer experience with docs, samples, and tooling.
• Build mobile products connecting devices to the payment platform.
• Collaborate with product, engineering, and customers on requirements.

Connaissances

iOS development

Kotlin

Public API design

Semantic versioning

Cross-platform awareness

Swift

Android development

SDKs and libraries

Developer experience

English

Formation

Bachelor's degree or equivalent in CS/SE

Outils

Jira

Confluence

Git

Google Workspace

Miro

Slack

Asana

Description du poste

Who We Are

Paymenttools is on a mission to transform the payment landscape for retailers in Europe. With more than 4.4 billion visitors per year in over 15,000 REWE Group stores and travel agencies across 21 countries, we know exactly what consumers and merchants need when exchanging goods for money. We believe in making payments seamless and invisible, linking them with value-added services within the framework of a reliable identity service. Our mantra: #wesolvepayn. We blend cutting-edge technology with stringent security to protect sensitive payment data while nurturing innovation in a cloud-native tech environment.

Who We Are Looking For

We’re looking for a (Senior) Mobile Engineer (d/f/m) with extensive iOS & practical Android experience to join our Mobile Team. You will help own and evolve the mobile technology at the heart of our payment ecosystem, including the WhiteLabelPay SDK used within Rewe applications, as well as mobile products such as SoftPOS applications and connectors bridging devices with the payment world.

This is more than a feature-development role. Our mobile components are integrated into products used by millions of people, so API stability, backwards compatibility, reliability, and an excellent developer experience matter enormously. You will take significant ownership of our iOS technology while also helping ensure that our Android and iOS implementations behave as one coherent product.

Your tasks

• Own, develop, and evolve the iOS implementation of our WhiteLabelPay SDK and future iOS applications.
• Design stable, intuitive, and developer-friendly public APIs that are easy for customers to integrate and difficult to misuse.
• Work across iOS and Android to ensure consistent behaviour, concepts, states, errors, and integration contracts between platforms.
• Contribute to Android development and architecture using Kotlin, collaborating closely with Android engineers while bringing strong cross-platform awareness.
• Improve the overall developer experience through high-quality documentation, sample applications, integration guidance, and tooling.
• Build and maintain mobile products beyond the SDK, including payment applications and components connecting mobile or IoT devices with our payment platform.
• Collaborate closely with product, engineering, architecture, customers, and other stakeholders to turn complex payment requirements into simple and reliable mobile interfaces.

Your Experience

• Several years of professional mobile engineering experience, with extensive native iOS development expertise
• Deep knowledge of the Apple ecosystem and modern iOS development, ideally including Swift and commonly used iOS frameworks and architectural approaches
• Practical experience developing Android applications or libraries with Kotlin, and the ability and willingness to work across both platforms when needed
• Experience building or maintaining SDKs, libraries, frameworks, or other developer-facing platform components
• Strong understanding of public API design, semantic versioning, backwards compatibility, deprecation strategies, and release management
• A solid architecture and product mindset—you think beyond individual tickets and consider maintainability, integration experience, and long-term evolution
• Fluent English, German skills are a plus
• Experience with payment technologies, SoftPOS, security-sensitive mobile applications, or regulated environments is a strong advantage—but not required

Our Benefits

• Deutschland ticket, subsidized subscription
• 1.000 euro annual learning and development budget + internal training platforms
• Discounts on travel, fashion, technology, and more through our corporate benefits
• REWE discount card for REWE group retailers
• Discounted membership with EGYM Wellpass
• Deutsche Dienstrad, affordable bicycle leasing
• Company provided tax services
• Insurance services

Perks of working with us

• Flexible working hours that fit your workflow, your time matters
• Language courses (English and German)
• Responsibility from day one
• Work with modern and agile software such as Google Workspace, Slack, Asana, Jira, Lattice, Miro and Confluence
• Company events including Hackathons and Company Days
• Ask us more about these!

Not a perfect match?

We are looking forward to getting to know you, so even if you feel that you don’t quite meet all the requirements, but the position still excites you, and you think you would love to work with us, please reach out! We explicitly encourage applicants within groups that are underrepresented in tech spaces today. We value all kinds of backgrounds and walks of life.