Senior Software Engineer (Enterprise AI Platform, UK) in London

About WRITER
WRITER is where the world's leading enterprises orchestrate AI-powered work. Our vision is to expand human capacity through superintelligence. We're proving it's possible—through powerful, trustworthy AI that unites IT and business teams together to unlock enterprise-wide transformation. With WRITER's end-to-end platform, hundreds of companies like Mars, Marriott, Uber, and Vanguard are building and deploying AI agents that are grounded in their company's data and fueled by WRITER's enterprise-grade LLMs. Valued at $1.9B and backed by industry-leading investors including Premji Invest, Radical Ventures, and ICONIQ Growth, WRITER is rapidly cementing its position as the leader in enterprise generative AI.

About the role
Imagine that you're stepping into a role where your code directly empowers the world's largest enterprises to safely adopt superintelligence. We're looking for an exceptional senior software engineer to join our enterprise AI platform team. In this pivotal role, you'll be at the forefront of expanding human capacity by building the secure, scalable foundation that allows our generative AI solutions to thrive in complex corporate environments. The impact of this work is massive—for example, in the CPG industry alone, our AI adoption is driving 69% revenue increases and 72% cost reductions.

This role is designed for a well‐rounded engineering generalist who leans heavily into generative AI, while also bringing a whole‐systems mindset to architectural design. If you thrive on proactivity without red tape and love owning projects from proposal to deployment, you'll shape the future of AI and contribute to a product that's changing how the world works.

What you'll do:

• Act as a whole‐systems thinker by making meaningful system design decisions and owning the architecture of core platform components from initial design through production deployment.
• Develop secure generative AI services and applications using Python and modern frameworks to drive enterprise‐wide transformation.
• Build and optimize high‐performance and low‐latency APIs and microservices for integrating advanced AI models and agentic workflows into our enterprise platform.
• Drive proactivity without red tape by clearly communicating changes, plans, and proposals to cross‐functional teams without waiting for a stamp of approval.
• Bridge the gap between backend services, infrastructure, and operations to ensure seamless deployments and scalable architecture.

What you need:

• 5+ years of hands‐on experience as a senior software engineer with a strong emphasis on Python development in production environments.
• Proven expertise and deep knowledge in building and deploying generative AI applications, understanding the nuances and caveats of leveraging LLMs, vector databases (e.g., Pinecone, Weaviate, pgvector), and modern open‐source agentic frameworks within a secure enterprise context.
• Hands‐on experience leveraging AI developer tooling like Claude, Cursor, or GitHub Copilot to accelerate and enhance your own engineering workflows.
• Practical experience with microservices architecture, RESTful APIs, and cloud platforms such as AWS, GCP, or Azure, including containerization with Docker and Kubernetes.
• Solid grasp of modern web technologies including FastAPI, Asyncio, and database systems like PostgreSQL.
• A Connect mindset thriving in collaborative settings where you actively engage with cross‐functional teams and mentor junior engineers to achieve shared goals.
• A Challenge spirit demonstrating exceptional problem‐solving skills to tackle complex technical hurdles and proactively suggest innovative improvements to our systems.
• An Own attitude taking full accountability for delivering high‐quality, resilient, and scalable code from conception through to production.

Nice to have:

• Exposure to enterprise architecture including practical experience implementing IAM, SSO, SAML, OAuth, OIDC, RBAC, and robust security best practices.
• Experience designing and building robust services for enterprise administration and billing systems.
• Experience navigating complex or legacy system migrations and the infrastructure side of deployments.

Benefits & perks (UK full‐time employees):

• Generous PTO, plus company holidays.
• Comprehensive medical and dental insurance.
• Paid parental leave for all parents (12 weeks).
• Fertility and family planning support.
• Early‐detection cancer testing through Galleri.
• Competitive pension scheme and company contribution.
• Annual work‐life stipends for wellness, learning and development.
• Company‐wide off‐sites and team off‐sites.
• Competitive compensation and company stock options.