Senior Software Engineer II, Backend

Poshmark•Redwood City, CA

22h

About The Position

Poshmark is looking for a Senior Software Engineer II to join our Core Platform team and build reliable, scalable, and high-performance backend systems that power our marketplace. In this role, you will independently own complex backend features and services from technical design through production. You will solve challenging engineering problems across distributed systems, make thoughtful technical trade-offs, and work closely with Product, QA, Infrastructure, and other engineering teams. You will also contribute to technical design discussions, mentor junior engineers, and help improve the reliability, maintainability, and operational excellence of the systems owned by the team.

Requirements

Bachelor’s or Master’s degree in Computer Science, Engineering, or a related technical discipline, or equivalent practical experience.
7+ years of professional software engineering experience, including experience building and operating production backend systems.
Strong foundation in computer science fundamentals, including data structures, algorithms, object-oriented design, and software design principles.
Proficiency in at least one backend programming language such as Ruby, JRuby, Java, or a comparable language.
Experience designing, developing, and maintaining APIs and backend services.
Experience working with distributed systems and understanding their scalability, reliability, and performance considerations.
Experience with databases, data modelling, caching, search technologies, or messaging systems.
Experience writing clean, maintainable, well-tested, and well-documented production code.
Strong debugging and problem-solving skills, including experience diagnosing issues in production environments.
Understanding of monitoring, observability, automated testing, deployment, and operational readiness.
Ability to independently drive technical work while collaborating effectively with engineers and cross-functional partners.
Strong written and verbal communication skills, with the ability to explain technical decisions and trade-offs clearly.
Demonstrated commitment to product quality, customer experience, and continuous improvement.

Nice To Haves

Experience with Amazon Web Services or another major cloud computing platform.
Experience with one or more of the following technologies: Ruby, JRuby, Java, MongoDB, Elasticsearch, RabbitMQ, and Linux.
Experience building cloud-native services for a high-traffic consumer or marketplace platform.
Experience with service-oriented or microservices-based architectures.
Experience with performance optimization, capacity planning, and production incident response.
Experience with email, push notification, or other large-scale messaging technologies.
Previous experience mentoring junior engineers, interns, or new team members.

Responsibilities

Design, develop, test, deploy, and operate scalable backend services that support Poshmark’s marketplace.
Independently own complex, well-defined technical initiatives from requirements and design through production rollout and ongoing support.
Translate product and technical requirements into reliable, maintainable, and extensible software solutions.
Make sound design and implementation decisions by evaluating scalability, performance, reliability, security, and operational trade-offs.
Develop and enhance APIs, data models, asynchronous workflows, and integrations across distributed systems.
Troubleshoot complex production issues, perform root-cause analysis, and implement sustainable fixes.
Improve system observability, monitoring, performance, fault tolerance, and operational readiness.
Participate actively in technical design reviews and provide constructive feedback through code reviews.
Collaborate with Product, QA, Infrastructure, and adjacent engineering teams to manage dependencies and deliver high-quality solutions.
Contribute to improving development processes, engineering practices, tooling, and team workflows.
Mentor junior engineers and support their technical development through design discussions, code reviews, and knowledge sharing.
Participate in production support and on-call responsibilities as required by the team.