Senior Software Engineer, Backend

About Posh We are all social creatures, but the dominant “social” companies today have evolved into digital loneliness machines, driving isolation, anxiety, and mental health challenges around the world. Human connection is lost. Posh is a beacon guiding us back. Posh enables anyone to build an IRL community based on shared interests, while connecting consumers with the communities of people just like them. Founded by event organizers who were frustrated with the growing loneliness epidemic and the tools available to build their own event brand, we’ve built the ultimate platform for launching, monetizing, and finding IRL communities of people just like you. In just 6 years, Posh has grown to a team of 70, expanded to 10M+ users, secured $70m in venture funding, and facilitated over $400M in transactions. About The Role We're looking for a Senior Backend Engineer to help build and scale the systems behind Posh's platform. You'll take ownership of backend services already running at real scale, with organizers and attendees on the other end of everything you ship. This is a hands-on IC role. You'll design APIs and services, make architecture calls that hold up under load, and push code quality up across teams beyond your own. You'll also mentor engineers earlier in their careers. This is an in-person role at our New York City office in SoHo, 5 days a week onsite. Key Responsibilities: Build and maintain the services and APIs that power Posh's platform, writing production code daily. Take end-to-end ownership of the backend systems you work on, from design through deployment and on-call. Address performance and reliability issues as usage grows, evolving systems already in production rather than designing around problems on paper. Instrument what you build and design security in from the start rather than adding it later. Build data models and pipelines that give organizers and the business actionable insight. Contribute to design reviews and code review outside your immediate scope, and weigh in on technical decisions that affect other teams. Mentor engineers earlier in their careers through code review, pairing, and direct feedback. Participate in technical interviews and calibration. Ideal Candidate: 5+ years of backend engineering experience, with a track record of shipping production systems in fast-paced environments. Deep expertise in backend fundamentals: APIs, data modeling, distributed systems, event-driven architecture. Proficient in technologies relevant to our stack (e.g., Java, Node.js, PostgreSQL, MongoDB, AWS or similar technologies). Experience with Infrastructure as Code (e.g., Terraform) and deploying containerized applications. Has scaled systems operationally, not just designed them on paper — you've watched performance regress under load and evolved architecture that was already live. Pragmatic about technology choices, and able to defend the tradeoffs you make. Communicates technical tradeoffs clearly to engineers, product, and business stakeholders. Experience at a consumer, social, or marketplace company is a plus. When applying, please include links to your GitHub profile or a portfolio of past projects. Posh provides equal employment opportunities to all employees and applicants for employment and prohibits discrimination and harassment of any type without regard to race, color, religion, age, sex, national origin, disability status, genetics, protected veteran status, sexual orientation, gender identity or expression, or any other characteristic protected by federal, state or local laws. This policy applies to all terms and conditions of employment, including recruiting, hiring, placement, promotion, termination, layoff, recall, transfer, leaves of absence, compensation and training. Posh is committed to providing reasonable accommodations for qualified individuals with disabilities in our job application procedures. Please let us know if you need assistance or accommodation due to a disability