Senior Software Engineer I, Backend

Overview

Powered by a vibrant community of 165 million members, Poshmark brings real people and taste to shopping through a social experience shaped by shared discovery. Buying and selling fashion feels simple, joyful, and personal, while every item tells its own story. Poshmark empowers sellers to grow meaningful businesses, keeps fashion in circulation longer, and gives shoppers access to unique and trusted finds, from everyday pieces to one-of-a-kind vintage and luxury.

We are seeking an experienced Senior Software Engineer I to join our Platform(Backend) team and contribute to the continued scalability and innovation of our backend systems. As a key technical contributor, you will play a critical role in building and optimizing the cloud-native infrastructure and services that power our high-traffic marketplace. The Poshmark community creates a new listing every 2 seconds and generates millions of likes, comments, and shares every single day — this is your opportunity to impact the core of that experience.

Responsibilities

• Lead the design, development, and deployment of scalable backend services and distributed systems.
• Help evolve our application and service delivery platform, leveraging cloud-native architectures, NoSQL solutions, queueing technologies, and search infrastructure.
• Architect and implement new product features using a data-driven, iterative approach with measurable impact.
• Drive performance tuning and system improvements to ensure reliability, scalability, and maintainability of key components.
• Collaborate with cross-functional teams — including Product, Design, DevOps, and QA — to deliver high-quality software aligned with business goals.
• Actively participate in code reviews, technical discussions, and mentoring of junior engineers.
• Identify and lead refactoring and technical debt reduction efforts to improve developer velocity and system health.
  
  

• Ramp up quickly on Poshmark’s codebase, cloud architecture, and development workflows.
• Take ownership of key components or services and contribute high-quality, well-tested code to production.
• Serve as a go-to technical resource within your immediate team.
• Drive cross-team collaboration to deliver features and improvements efficiently and effectively.
  
  

• Lead the technical execution of complex initiatives with multiple dependencies and stakeholders.
• Influence architectural decisions and contribute to long-term platform and service strategy.
• Drive engineering excellence through best practices, tooling, and process improvements.
• Provide mentorship and technical leadership across the backend engineering team.
  
  

• 5+ years of professional backend software engineering experience, including designing and scaling distributed systems.
• Strong foundation in computer science, including data structures, algorithms, and software design principles.
• Proficiency with backend programming languages such as Ruby and/or Java.
• Experience working with technologies like MongoDB, ElasticSearch, RabbitMQ, and Redis.
• Strong understanding of RESTful API design and implementation.
• Experience with scalability, performance optimization, and systems-level problem solving.
• Familiarity with microservices architecture and cloud platforms (e.g., AWS, GCP) is a plus.
• Bachelor's or Master’s degree in Computer Science or a related field.
• Strong communication skills and a user-centric, quality-first mindset.