Senior Full Stack Engineer / London

About YASO YASO is the operating system for international brands in China, built by a team of China experts, technologists, and startup operators. We provide a plug-and-play solution that manages the full cross-border ecommerce and social commerce stack - from store operations and pricing to influencer partnerships and logistics - all powered by our proprietary technology. We give brands full visibility across every performance layer, including traffic, conversion, revenue, influencer ROI, content, and stock. For the first time, brands can monitor and manage their China business in real time, with data that is transparent, measurable, and actionable. By replacing opaque legacy models with a unified, data-driven system, YASO enables international brands to take back control of their growth in China. Following our Series A fundraise, we are expanding our global team across London, Shanghai, and beyond to shape the future of cross-border retail. The Role Work with our Product Manager and engineering team to build the customer-facing platform features and internal tools that enable enterprise customers to use YASO self-service. You'll ship data integrations, operational tooling, and standalone product capabilities that will enable us to scale our customer base 10x. You report to our Founder (James, based in London), with daily collaboration with your squad, PM and YASO's ops team in Shanghai. You'll work with our international teams in Europe and Shanghai with regular opportunities for in-person collaboration across the team. Within 60 days, you've shipped at least one feature that our ops team or customers use weekly that you've owned end to end. You Will Build end-to-end features from database schema to UI that solve real operational bottlenecks and deliver measurable impact for our team and customers Design and implement APIs that power both internal tools and customer-facing platform capabilities, ensuring they're secure, scalable, and maintainable Translate product requirements into technical solutions. Work with our Product Manager to shape specs, assess feasibility, and flag architectural concerns before they become problems Own your code in production. Deploy, monitor, debug performance issues, and maintain the systems you build Collaborate across timezones. Daily async work with our Shanghai engineering team, building on shared data infrastructure and contributing to our unified codebase Participate in EU-based on-call rotation to ensure system reliability Shape our engineering culture through thorough code reviews, documentation, and sharing best practices with the team Drive our roadmap, providing technical input on our strategy and product roadmap Fluent English language speaker.

Experience:

5-8 years as a full-stack engineer building production web applications 2+ years at early-stage startups (seed to Series B) Led technical delivery of 2+ substantial features end-to-end (0→production), including architecture decisions

Technical Skills:

Expert-level TypeScript/JavaScript and modern frameworks (Next.js, React, or equivalent) Strong database skills (Postgres, MySQL) - can design schemas, optimize complex queries, debug performance issues independently Solid DevOps foundation: CI/CD, Docker, cloud infrastructure (AWS/GCP/similar), comfortable troubleshooting production issues Write code that requires minimal review - colleagues trust your technical judgment

Product & Architecture:

Experience collaborating with Product Managers, shaping requirements and pushing back when needed Can take ambiguous problems, propose solutions, and execute without constant oversight Comfortable making architectural trade-offs (build vs. buy, scale now vs. later) Experience mentoring junior engineers through code review and pairing

Working Style:

Highly independent: You unblock yourself and know when to escalate Pragmatic about technical debt and scope Product-minded: You challenge requirements that don't make business sense Thrive in startup ambiguity and rapid iteration AI-augmented: You can get the most out of LLM assistants

Bonus:

Experience building B2B SaaS products Familiarity with LLM APIs (OpenAI/Anthropic) and vector databases Any Mandarin Chinese language skills Our Process Initial screen (30 min) - Call with our Founder James Technical interview (90 min) Reference checks - We'll contact 2 references Call with a second YASO founder

• The opportunity to shape the marketing engine of a fast-growing Series A company redefining cross-border commerce.
• A collaborative, high-performance environment spanning London, Shanghai, and beyond.

Competitive salary, performance-linked incentives, and flexible working arrangements. Direct exposure to senior leadership, global brand partners, and leading consumer platforms.