Backend Software Development Engineer 2

About the role: 

The OfferUp Connect team builds the moments that turn a listing into a sale. Every chat between buyers and sellers, every offer notification, and every saved-search alert runs through services we own, from messaging and notifications to location, meetups, and the subscriptions sellers pay for. We run high-volume Java microservices and streaming pipelines, integrate with partners like Braze, Amazon Pinpoint, Apple, and Google, and use experimentation to decide what ships.

We also take on high-visibility work beyond our domain. Connect built OfferUp's video infrastructure for listing videos and LLM-powered catalog enrichment on Amazon Bedrock, both company priorities that changed what buyers see every day. The roadmap is wide open for someone who wants to help shape it.

As a Software Development Engineer II (Backend) , you'll own features from concept to rollout: designing and writing well-tested code, launching experiments, and measuring results with Product, Design, and Data partners. You'll raise the quality of the code around you and get the chance to join the next project like video or catalog enrichment.

Here’s more of what you will get to do:

• Design, build, and deploy backend services and event-driven pipelines for messaging, notifications, location, and subscriptions
• Improve the reliability, latency, and delivery rates of high-volume messaging and notification systems, including retries, rate limiting, and frequency capping
• Integrate with and operate third-party platforms such as Braze, Amazon Pinpoint, Apple and Google push services, and app store billing
• Own features end-to-end: plan, design, develop, deploy, measure, and iterate
• Break down complex engineering problems into achievable tasks and deliver them within committed timeframes
• Work collaboratively with cross-functional teams (Product, Design, Data Science, Marketing, and iOS, Android, and web engineers) to design and implement new features
• Contribute to A/B tests and use experimentation results to decide what ships
• Actively participate in code reviews and enforce good patterns, testing, and edge-case handling
• Coach and mentor junior team members, new hires, and interns
• Create shared components, utilities, and services that improve team velocity across the stack
• Maintain and improve the runbooks, alerting, and monitoring for the features you ship
• Participate in a reasonable on-call rotation with the rest of the team
• Use AI coding tools (Claude Code, Gemini, and similar) to increase your daily development velocity and code quality
• Become a subject matter expert in one or more of the team's sub-domains: messaging, notifications and campaigns, location, or subscriptions and promotions

You’ll thrive in this role if you have:

• 5+ years of professional software engineering experience
• Demonstrated ability to own the delivery of multiple features end-to-end (plan, design, develop, and deploy) with high efficiency, including breaking down engineering problems into achievable tasks
• Strong coding skills in Java, with a working understanding of microservices and distributed-systems fundamentals
• Good knowledge of data structures and object-oriented design
• Working knowledge of asynchronous, event-driven systems (queues, pub/sub, or streams), including retries and idempotent processing
• Hands-on experience using AI coding tools (Claude Code or similar) in a real engineering workflow, and a point of view on when they help and when they don't
• A habit of following good coding patterns, writing appropriate tests, considering trade-offs, and seeking out edge cases
• Comfortable giving and receiving feedback in code reviews
• A bias toward shipping, learning from production, and iterating quickly
• An insatiable desire and ability to learn
• BS or MS in Computer Science, or equivalent practical experience

Helpful, but not required:

• Fluency in another modern object-oriented programming language
• Experience with TypeScript and Node.js
• Experience with Agile development
• Experience building and integrating with REST APIs
• Experience with AWS services such as DynamoDB, SQS, SNS, Lambda, and ElastiCache (Redis)
• Experience with notification and engagement platforms (Braze, Amazon Pinpoint, APNs, FCM) or in-app subscription billing (App Store, Google Play)
• Experience with stream processing frameworks such as Apache Flink or Kafka Streams
• Experience with A/B testing platforms (Statsig, LaunchDarkly, Optimizely) and analytics warehouses (BigQuery, Snowflake)
• Experience consuming or integrating LLM-based APIs (e.g., Bedrock, Vertex AI, OpenAI)
• Familiarity with Kubernetes, Helm, and CI/CD pipelines