Mid-Level Software Engineer (SWE 2)

About Downstream

Downstream is a marketplace platform transforming the waste and construction industries from the ground up. We're on a mission to bring simplicity, transparency, and sustainability to two of the most essential — but often overlooked — sectors of our economy.

We make it easy for contractors, builders, and businesses to find and book critical services like dumpster rentals, hauling, site services, and equipment — all in a few clicks. No endless calls, no confusing pricing, no waiting around. Our platform connects customers with vetted, reliable providers so they can get what they need, when they need it.

We're not just about convenience — we're about impact. By streamlining logistics and digitizing the supply chain, we're helping reduce waste, cut emissions, and build a cleaner, more sustainable future. Let's build better, together.

About the role

We're looking for a Mid-Level Software Engineer who can independently own product features from implementation through production. You'll build and maintain Django applications, APIs, and data models that power the Downstream marketplace, while helping embed intelligent automation into logistics, pricing, and supplier matching. You'll contribute to AI integrations and multi-step workflows, collaborate across teams, and help junior engineers grow.

What you'll do

• Design, build, test, and maintain Django applications, REST APIs, and data models supporting core marketplace functionality
• Own medium-sized features from technical discovery and implementation through deployment, monitoring, and iteration
• Develop reliable integrations with PostgreSQL or similar relational databases and external services
• Integrate AI tools and frameworks such as OpenAI, LangChain, LangGraph, Hugging Face, or custom orchestration into production application workflows
• Build and improve multi-step AI workflows that can interpret context, use tools, and complete defined tasks with appropriate controls
• Partner with product and operations stakeholders to identify automation opportunities in logistics, pricing, supplier matching, and customer or supplier workflows
• Write maintainable, testable code; participate in code reviews; and contribute to API and data-model design
• Mentor junior engineers through pairing, feedback, documentation, and practical examples

Role specifics

• Ownership: independently ships medium-sized features and is accountable for their quality and production behavior
• Technical focus: Django/Python, REST APIs (DRF or GraphQL experience is a plus), PostgreSQL, integrations, and automated testing
• AI responsibility: implements AI-powered features and workflow components, including tool integrations, structured outputs, and appropriate validation and error handling
• Collaboration: works with product, operations, and engineering peers to translate business problems into maintainable technical solutions

Who you are

• You've built and shipped Django/Python applications, APIs, or meaningful production features
• You can independently design and implement REST APIs and work confidently with relational databases
• You have practical experience integrating LLMs or AI tools; familiarity with LangChain, LangGraph, OpenAI, Hugging Face, or custom agent frameworks is valuable
• You understand the difference between a simple model API call and a multi-step workflow that interacts with tools, data, and business rules
• You write testable code and make thoughtful tradeoffs between speed, reliability, and maintainability
• You enjoy mentoring teammates and taking ownership in an evolving startup environment
• Construction technology, logistics, equipment rentals, or marketplace experience is a plus

Compensation

$95,000–$125,000 per year (Series A compensation band).

Benefits

Downstream is an equal opportunity employer. We consider all applicants for employment without regard to race, color, religion, sex, sexual orientation, gender identity or expression, national origin, age, disability, genetic information, veteran status, or any other protected status under applicable law.

• Medical, dental, and vision insurance
• 401(k) with a company match
• Company equity — be an owner in what we're building
• Paid time off, paid holidays, and floating holidays
• Parental and bereavement leave