Backend Engineer, Expansion

Stripe is a financial infrastructure platform that enables businesses to accept payments, grow revenue, and accelerate new opportunities.

As a backend engineer on the Expansion pod, you will architect and build server‑side systems and LLM orchestration layers that power intelligent, dynamic user experiences across acquisition journeys. Your work will focus on integrating large language models into production‑grade services that are reliable, performant, and safe.

• Design and build APIs, data pipelines, and inference infrastructure for interactive content tools such as calculators, generators, and templates.
• Implement user‑first feedback mechanisms to continuously improve content and product offerings.
• Integrate third‑party software and create seamless workflows to maximize the value of new features.
• Maintain reliability, security, and responsible AI practices across all LLM‑driven features, including content filtering, PII handling, rate limiting, graceful degradation, and output guardrails.
• Collaborate closely with a team of technically sophisticated engineers and cross‑functional partners.

Minimum requirements

• 5+ years of backend development experience, with emphasis on building user‑facing APIs and services.
• Strong coding skills and experience writing clear, maintainable code in a team environment.
• Familiarity with LLM APIs and concepts such as prompt engineering, token management, embedding models, retrieval‑augmented generation, or function calling.
• Experience building and operating distributed backend systems, including service‑oriented architectures, asynchronous processing, caching layers, and production monitoring and alerting.
• Passion for building solutions that drive growth and enablement.
• Excellent verbal and written communication skills.

Preferred qualifications

• Ability to stitch different services and processes together, even with minimal prior exposure.
• Experience developing interactive tools and integrating them with existing systems.
• Experience building complex interactive tools with state management and data fetching.
• Experience with data pipeline orchestration tools (e.g., Airflow, Dagster, Temporal) and structured output parsing from LLMs.
• Experience with prompt versioning, A/B testing model outputs, or building model gateway and routing layers to support multiple providers (OpenAI, Anthropic, open‑source models).
• Proficiency with React, focused on interactions, animation, performance, and polish.
• Experience with A/B testing, synthetic monitoring, or accessibility testing.