Software Engineer (Backend, AI Systems)

Locai Labs is The British Foundational AI Company, based in Paddington, London. We are dedicated to building world‐class large language models at the forefront of cost, efficiency, and capability. Our mission is to advance cutting‐edge AI from within the UK by combining deep technical innovation with engineering excellence, creating scalable models and intelligent systems that power next‐generation applications for consumers and enterprises alike.

Our work spans across:

• Bespoke agentic applications for enterprise and consumer domains
• APIs and developer tools that enable intelligent automation

The Role

We are seeking a Software Engineer (Backend, AI Systems) to design and build the backend systems, APIs, and tools that power Locai Labs' AI models and agentic platforms. You will work on a diverse range of challenges, from model‐serving APIs and data pipelines to infrastructure for intelligent agents and automation frameworks. This is a hands‐on engineering role for someone who enjoys solving complex technical problems and shipping impactful products. You will collaborate closely with the CTO and engineering team to design, build, and scale production systems that integrate AI into real‐world applications.

Responsibilities

• Design and develop backend systems and APIs for AI‐driven products and agent frameworks
• Integrate LLMs into scalable, production‐ready systems
• Build internal tools and services to manage agents, workflows, and orchestration logic
• Collaborate with frontend, infrastructure, and research teams to deliver cohesive product experiences
• Contribute to system architecture, technical design, and engineering best practices
• Write clean, maintainable, and well‐tested code

Required Experience

• 2–5 years of professional software engineering experience, ideally working on backend systems, APIs, or AI‐related products
• Strong understanding of backend architectures, REST/GraphQL APIs, and data modelling
• Experience with containerisation (Docker) and cloud platforms (GCP, AWS, or similar)
• Familiarity with LLM or AI APIs
• Exposure to agentic frameworks (LangChain, LlamaIndex, Semantic Kernel, etc.)
• Practical experience with databases (SQL / NoSQL)
• Strong foundation in software design principles and systems thinking
• Comfortable working in a fast‐paced, early‐stage start‐up environment with ownership and autonomy

Nice to Have

• Experience with vector databases or embedding pipelines
• Understanding of event‐driven or real‐time systems (Kafka, Pub/Sub, etc.)
• Knowledge of API authentication, access control, or multi‐tenant architectures
• Familiarity with React or other front‐end frameworks (for internal tools)
• Interest in applied AI research, model fine‐tuning, or reasoning agents

Environment and Culture

You will join a small, highly technical team where your contributions directly shape the company's technology and products. We value ownership, curiosity, and pragmatism; every engineer at Locai Labs helps define architecture, infrastructure, and product direction. You will work on‐site at our Paddington HQ, collaborating closely with the CTO and engineering team in a transparent, fast‐moving, and innovation‐focused environment.

Application Process

• Application Review – We evaluate your background and experience.
• Take‐Home Technical Assessment – A short exercise to demonstrate your engineering approach.
• Technical Interview – Discussion of technical depth, design thinking, and problem‐solving.
• On‐Site Session at HQ – Collaboration exercises and technical discussions with the team.
• Offer – Formal offer and next steps.

If this sounds like you, we would love to hear from you. Apply directly via the form below: Application Form (Strictly no agencies or recruiters. We are only accepting direct applications.)

Seniority level: Mid‐Senior level

Employment type: Full‐time

Job function: Engineering and Information Technology Software Development