Senior iOS Developer (Ad SDK Infrastructure)

We are looking for a Senior iOS Developer with strong expertise in native SDK development to join the AdTech project. In this role, you will contribute to the development and maintenance of production-grade mobile advertising SDKs used by publishers worldwide. You will work with release-critical iOS SDK products distributed through CocoaPods and integrated into third-party mobile applications. The project requires deep understanding of SDK architecture, release processes, stability, and integration support rather than standard mobile application development. We at Sigma Software offer the opportunity to work on technically challenging products, collaborate with experienced engineering teams, and contribute to high-scale mobile monetization solutions used in real production environments. CUSTOMER Our Customer is a technology company operating in the mobile advertising industry and focused on building scalable in-app monetization solutions. The company develops mobile advertising SDKs for iOS and Android platforms that are integrated into publishers’ applications and support multiple ad formats, tracking systems, and communication with advertising infrastructure such as SSPs and ad servers. The environment is highly quality-oriented due to the production-critical nature of SDK releases and external integrations. PROJECT The project is focused on the ongoing development and maintenance of existing open-source iOS SDKs that serve as a core part of the Customer’s in-app advertising infrastructure. These SDKs handle ad rendering, timeout management, tracking beacons, and communication with ad-serving systems while abstracting technical complexity from publishers integrating the solution into their applications. You will participate in feature development, SDK architecture improvements, release management, and integration support while ensuring high stability and backward compatibility across supported iOS environments. Key Technologies: Swift, Objective-C, CocoaPods, iOS SDK, Automated Testing, Mobile Advertising Technologies. Develop and maintain native iOS SDK functionality using Swift and Objective-C Contribute to feature development for existing open-source SDK products Improve SDK architecture, stability, scalability, and maintainability Support SDK packaging, versioning, and distribution through CocoaPods Ensure high release quality through automated testing and device-based validation Investigate and resolve bugs, integration issues, and publisher-reported problems Collaborate with Backend, Android, QA, and Product teams Optimize SDK performance, reliability, and compatibility across supported iOS environments Participate in release planning and quality assurance activities for SDK releases Provide technical support for third-party integrations and troubleshooting activities At least 5 years of production iOS development experience Strong commercial experience with Swift and Objective-C Hands-on experience developing native iOS SDKs or reusable iOS libraries Strong understanding of SDK architecture principles and mobile platform internals Experience with CocoaPods and SDK packaging/distribution workflows Proven experience with SDK versioning, release processes, and backward compatibility management Practical experience with automated testing and device-based testing approaches Understanding of production support processes and troubleshooting complex integration issues Ability to work independently and take ownership of SDK quality and delivery At least an Upper-Intermediate level of English WILL BE A PLUS Experience leveraging AI tools for testing and coverage analysis Familiarity with SSPs, ad servers, banner and video advertising, and tracking pixels Experience working with open-source SDKs Experience supporting third-party integrations and publisher-side troubleshooting PERSONAL PROFILE Committed to high standards and precision in every deliverable Strong sense of ownership and proactive approach in fast-paced, release-sensitive environments Effective both as a collaborative team player and as an independent contributor Self-motivated and result-oriented mindset