Software Development Engineer II

About the role: As a Software Development Engineer II, you will play a critical role in maintaining and evolving OfferUp's client engineering platform and app ecosystem, as well as leading efforts to build systems that detect and prevent fraudulent behavior in our marketplace. You will ensure app stability, performance, and developer efficiency by tackling complex technical challenges, collaborating across teams, and driving innovation. The systems you build will help maintain our community guidelines and support our partner team's growth and business strategies, focusing on key issues such as account takeovers, Phishing, Payment chargebacks, and Prohibited Items. As a Fullstack Software Development Engineer, you will build end-to-end, highly scalable systems and user experiences to detect and prevent fraud, while continuously improving our engineering/operational excellence.   This role is only available outside the US and not available to any individual based within the US or any US territory.   Here’s more of what you will get to do: You will create and deliver new web experiences for OfferUp using web technologies such as NodeJS, React, and React Native. Design, develop, and maintain robust and scalable backend services and APIs to power features across web and mobile platforms. Work collaboratively with cross-functional teams across OfferUp to design and implement new features. Enforce best practices and drive code quality in existing applications (mobile and web). Break down complex engineering problems into achievable tasks and deliver them within committed timeframes. Actively participate in code reviews. Coach/Mentor junior team members, new hires, or interns. Create shared components and utilities that improve team velocity. You’ll thrive in this role if you have: 3+ years professional software engineering experience Demonstrated ability to own the delivery of multiple features end-to-end (plan, design, develop, and deploy) with high efficiency. Proficient in 1 or more core languages (e.g. Javascript, Typescript) Demonstrate strong fullstack coding skills, including front-end technologies (HTML, CSS, Javascript, React, React Native) and expertise in building highly scalable, reliable backend services, while following good coding patterns and seeking out edge-cases. Experience designing, building, and maintaining scalable backend services and APIs (e.g., using Java or similar server-side technologies). Strong coding skills in Java(required), and any other modern programming language coupled with strong knowledge in object-oriented design and microservices architecture Solid understanding of database design (relational and/or NoSQL) and data modeling. Good knowledge of Data Structures An insatiable desire and ability to learn You desire a fast moving, continuous flow development environment Experience with cross browser compatibility, client side security, browser tuning, and optimization techniques/tools. Knowledge in web optimization performance and design patterns (e.g., responsive design vs. optimized design). Experience with GraphQL BS or MS in Computer Science or equivalent experience Helpful, but not required: Experience with Agile development Experience with AWS Cloud infrastructure Experience around any of the following: web package managers, Bower, bundler system, NodeJS, Python, webpack Github repo with your own code we can view  About OfferUp: OfferUp is dedicated to creating the simplest and most trusted way for people to buy, sell, and connect in their local communities. One of the top local marketplace apps for local buyers and sellers in the U.S., OfferUp makes it easy for people to discover more of what they need—from great deals and secondhand goods to jobs, services, home rentals, and more—right in their own communities. Our trusted platform empowers millions to connect, thrive, and move life forward.  Available on iOS and Android, OfferUp has consistently ranked among the top shopping apps. Founded in 2011 and based in Bellevue, WA, OfferUp serves local markets nationwide and was used by more than 1 in 6 adults in the U.S. in 2024. OfferUp is backed by leading investors, including Andreessen Horowitz, Warburg Pincus, GGV Capital, T. Rowe Price, and Coatue Management. https://about.offerup.com More About OfferUp At a Glance Top 10 Shopping app in the App Store and Google Play Store for three years 15%+ of adults in several major markets use OfferUp every month (LA, Miami, Phoenix, Seattle, Las Vegas, Riverside, Orlando) OfferUp works directly with nearly 2000 US law enforcement agencies to build trust in local communities OfferUp is unleashing the power of local, and we’ve built a dynamic team to do it. To learn more about working at OfferUp, check out https://about.offerup.com/people  OfferUp provides equal employment opportunities (EEO) to all employees and applicants for employment without regard to race, color, religion, sex, national origin, age, disability, or genetics. In addition to federal law requirements, OfferUp complies with applicable state and local laws governing nondiscrimination in employment in every location in which the company has facilities. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, transfer, leaves of absence, compensation, and training. OfferUp expressly prohibits any form of workplace harassment based on race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, genetic information, disability, or veteran status. Improper interference with the ability of OfferUp’s employees to perform their job duties may result in discipline up to and including discharge.