Senior Software Engineer, ACE at Reddit

United Kingdom

Reddit is a community of communities. It’s built on shared interests, passion, and trust, and is home to the most open and authentic conversations on the internet. Every day, Reddit users submit, vote, and comment on the topics they care most about. With 100,000+ active communities and approximately 121 million daily active unique visitors, Reddit is one of the internet’s largest sources of information. For more information, visit www.redditinc.com. Location: This role is based in the UK. Don't live near our office? No worries: you can work remotely from anywhere in the UK. About the Team The Ads Creative Effectiveness team is aimed at improving the impact of ad creative at Reddit through generative and predictive products. We adapt and finetune LLMs/VLMs to help advertisers make impactful images, videos, text and more. We build performance predictors to understand and rank ad components, ensuring the advertiser ships the best possible campaigns. We construct insight and recommendation engines to guide advertisers towards best practices and key enhancements, distilling knowledge about what works at Reddit to supercharge their performance. About the Role: Reddit’s newly minted Ads Creative Effectiveness team sits at the heart of our creative strategy, building GenAI and predictive products that help advertisers ship high-impact campaigns. We are searching for a Sr. Software Engineer to help us build the future of generative products for ad creative at Reddit - from contributing to the development of best-in-class image, video and copy generators that leverage Reddit’s best practices, performance-guided generations that maximize clicks and conversions, and brand safe, product preserving image/video editing pipelines at scale. Responsibilities: Lead Creative Engineering Architecture: Drive the design and implementation of high-performance backends for ad creative generation. You will own the architectural vision for brand asset preservation and style consistency, ensuring our GenAI stack is modular, extensible, and seamlessly integrated into Reddit’s infrastructure. Advanced Editing & Asset Workflows: Lead the development of end-to-end image and video editing engines. You will design the underlying APIs and logic that allow for complex asset manipulation while maintaining strict, automated adherence to brand guidelines. Scale Performance Feedback Systems: Architect the infrastructure that bridges the gap between ad performance (CTR, CVR) and the creative engine. You will build scalable systems to ingest high-volume performance data and programmatically optimize the generation flywheel. Optimize Model Orchestration & Efficiency: Solve complex engineering challenges around high-concurrency inference, latency optimization, and cost-efficient scaling at Reddit's global volume. Robust Safety & Compliance Systems: Design and maintain mission-critical middleware for content filtering and compliance. You’ll ensure our safety layers are resilient, low-latency, and capable of preventing non-compliant or infringing content from reaching the platform. Cross-Functional Technical Leadership: Partner deeply with Product, UX, and Ads ML leadership to help define the technical roadmap for ACE. You’ll translate broad business objectives into concrete technical designs and build integrations into the Ad Manager UI and delivery stacks. Engineering Excellence: Raise the bar for code quality, system reliability, and documentation within the team. You will lead design reviews, mentor mid-level engineers, and implement guardrails that protect the integrity of our advertiser and user experiences. Required Qualifications: Expert Software Engineering & System Design: Extensive experience architecting and scaling distributed backend systems (e.g., Python, Go). You have a proven track record of designing robust microservices and APIs that are not only performant but also extensible and easy for others to build upon. Applied AI/ML Systems Engineering: Strong experience bridging the gap between ML models and production software. You understand the nuances of model serving, building resilient data pipelines for LLMs/VLMs, and optimizing the infrastructure required for real-time generative workflows. Strategic Product Engineering: A deep understanding of how technical decisions impact the business. You don't just build features; you partner with Product to define them, translating complex advertiser needs into scalable technical roadmaps that drive revenue and retention. Operational Excellence & Ownership: A "startup mindset" paired with senior-level discipline. You have a bias for action but prioritize system reliability, observability, and long-term maintainability, even when moving fast in ambiguous environments. Technical Leadership & Influence: Exceptional communication skills with the ability to build consensus across Product, Design, and ML teams. You are adept at explaining complex technical trade-offs to non-technical stakeholders and driving technical alignment across the organization. Mentorship & High Standards: A passion for raising the engineering bar. You take pride in conducting thorough design and code reviews, mentoring junior/mid-level engineers, and fostering a culture of technical excellence within the team. Domain Expertise in Creative Tooling: Proven experience building complex asset-heavy systems—such as automated image/video processing pipelines or high-scale content creation workflows. Benefits: Global Benefit programs that fit your lifestyle, from workspace to professional development to caregiving support Family Planning Support Gender-Affirming Care Mental Health & Coaching Benefits Group Personal Pension Scheme with Employer match Private Medical and Dental Scheme Income Replacement Programs Bike to Work scheme Flexible Vacation & Paid Volunteer Time Off Generous Paid Parental Leave In select roles and locations, the interviews will be recorded, transcribed and summarized by artificial intelligence (AI). You will have the opportunity to opt out of recording, transcription and summarization prior to any scheduled interviews. During the interview, we will collect the following categories of personal information: Identifiers, Professional and Employment-Related Information, Sensory Information (audio/video recording), and any other categories of personal information you choose to share with us. We will use this information to evaluate your application for employment or an independent contractor role, as applicable. We will not sell your personal information or disclose it to any third party for their marketing purposes. We will delete any recording of your interview promptly after making a hiring decision. For more information about how we will handle your personal information, including our retention of it, please refer to our Candidate Privacy Policy for Potential Employees and Contractors. Reddit is proud to be an equal opportunity employer, and is committed to building a workforce representative of the diverse communities we serve. Reddit is committed to providing reasonable accommodations for qualified individuals with disabilities and disabled veterans in our job application procedures. If, due to a disability, you need an accommodation during the interview process, please let your recruiter know.