Senior Software Engineer, Full-stack in London

At Pairwise, we are a team of engineers, operators, and builders focused on enabling the next generation of technical talent to do their best work. We partner with leading technology companies to deliver high-performance engineering solutions across embedded systems, networking, semiconductors, and software. Our teams have contributed to some of the most advanced products in consumer, infrastructure, and communications technologies. This full‑time role offers the chance to work on‑site with a global leader in the technology industry, contributing to impactful, technically challenging projects in a high‑caliber and fast‑moving environment.

Pairwise is reinventing technical staffing from the ground up, building an AI‑powered platform to handle the entire employment lifecycle — from recruiting to offboarding. We’re a small, experienced, and relentlessly driven team that ships fast and holds a high bar for quality. We’re looking for a senior full‑stack engineer who thrives in high‑ownership environments, takes pride in clean architecture across the stack, and wants to help shape both the product and the team as we grow. This isn’t a standard CRUD app role. It’s a rare opportunity to join early, influence product direction, mentor the engineers who join after you, and build the complex orchestration and user experience behind a company solving real problems at scale.

We’re looking for someone who:

• Is a builder at their core – comes alive creating, iterating, and shipping. Equally comfortable wiring up a Django service, designing a React interface, and stitching the two together.
• Owns problems end to end. You don’t wait for tickets or detailed specs – you identify the business goal, figure out the logic and UX needed, and build the solution from scratch.
• Leads by example. You raise the bar for the people around you through thoughtful PR reviews, mentorship, and bringing ideas to the table instead of waiting to be told what to build.
• Brings energy and creativity to the work. Strong product instincts, real opinions in roadmap discussions, and enjoys ideation as much as execution.
• Obsesses over details. Can’t rest with flaky code, hallucinated outputs, or unresolved bugs – and makes time to get things right.
• Learns fast and thrives under pressure. Jumps into unfamiliar territory (like new LLM frameworks) without hesitation, wants to wear multiple hats, and wants to be pushed to grow every day.

Responsibilities:

• Architect and ship core product end to end. Design and maintain complex logic flows (Python/Django) and responsive, well‑designed user interfaces (React).
• Build and refine our Applied AI layer: RAG workflows, agentic behaviors, LLM orchestration, and the eval pipelines that keep them reliable.
• Own technical planning. Take high‑level product goals, turn them into concrete implementation plans, and break the work into Jira tickets the rest of the team can pick up and run with – without needing a PM to do it for you.
• Help shape what we build, not just how. This is a creative, high‑agency role – you’ll be in the room when we’re deciding the roadmap, and your instincts about what will best serve our customers will carry real weight.
• Act as a technical lead for the team – review PRs, mentor interns and engineers, and help shape the engineering culture and standards as we grow.

Requirements:

• 5+ years of professional engineering experience, with strong production work in both Python/Django and React.
• Deep, working understanding of databases, schema design, SQL, and data modeling. PostgreSQL preferred.
• Hands‑on Applied AI experience: integrating LLMs into production applications, working with RAG, LangChain/LlamaIndex, prompt engineering, or building eval pipelines.
• A track record of taking vague requirements and shipping complete features from scratch. We’re looking for meaningful side projects, open‑source contributions, published research, or independent work during a graduate program.
• Degree in Computer Science, Electrical Engineering, or another related technical field. Advanced degree (MS or PhD) is preferred.

Nice to haves:

• Experience mentoring and leading other engineers.
• Experience with cloud platforms (AWS, GCP, or Azure).
• Familiarity with data science and analytics concepts.
• Experience designing systems that scale.
• Experience shipping products end to end, with a strong sense for UI/UX.

Why join us:

• Ownership and responsibility – real impact from day one on product, technical direction, AI strategy, and the engineering culture we’re building.
• Fast learning and growth, working closely with experienced founders on hard technical and product problems, with room to grow into broader technical leadership as the team scales.
• Competitive compensation and benefits.

Pairwise offers competitive compensation and access to a range of benefits for employees, including premium PPO and HMO medical insurance coverage, dental, vision, FSA, life insurance, short/long‑term disability insurance, a company‑matched 401(k) plan, and a generous PTO policy. We are proud to work with engineers and professionals who want to make an impact through their craft. If you’re looking to be part of a team that values technical excellence, autonomy, and practical problem solving – we’d love to hear from you!

Pairwise is an equal opportunity employer. We are committed to building a diverse team and fostering an inclusive workplace. All qualified applicants will receive consideration for employment without regard to race, color, religion, gender, sexual orientation, gender identity or expression, national origin, age, disability, veteran status, or any other legally protected status.