Senior Back-End Engineer in London

We are a global company with a mission to advance the art and technology of visual experience. We know that creating an inclusive environment that values and encourages different perspectives is critical for our success, and the success of our people. We are learning, listening and taking action to be better and foster trust in our community. Our goal is to ensure every person working at Foundry feels safe and free to be themselves, to share their ideas or concerns and that there is equal access to opportunities for all.

THE ROLE

This is an opportunity to join the founding engineering team for Reactor, a new product initiative that combines emerging AI workflows with Foundry's world-class expertise in creative and VFX software. As a Senior Back-End Engineer, you will design and implement the core services, orchestration systems, cloud infrastructure, and execution pipelines that power Reactor's fast-moving, hybrid compute workflows.

You will work in a discovery-led environment where rapid experimentation, vertical-slice prototypes, and user validation drive the roadmap. You'll collaborate closely with the Lead Engineer, Front-End Engineers, Product Manager, and Creative Director to build scalable yet flexible systems that support AI inference, media processing, distributed workloads, timeline-driven tasks, and interactive artist workflows.

This role requires strong cloud engineering skills and fluency with the practical application of modern AI technologies. You should be inventive, resourceful, and able to transform incomplete or ambiguous product ideas into working solutions rapidly and reliably. You'll embody Foundry's values by grounding decisions in customer workflows, sharing openly across disciplines, and experimenting boldly with the right guardrails.

Job Requirements

• Experience

• 5+ years of back-end software engineering experience, ideally in cloud-based or SaaS environments.
• Proven success building distributed systems, orchestration layers, or high-performance services for media, AI, or computational workflows.
• Demonstrated ability to ship rapid prototypes and iterate based on customer feedback.
• Strong experience breaking down high-level requirements into actionable engineering work.
• Comfortable interacting directly with customers or partners to gather insights and validate system behaviours.

• Expert-level proficiency in Python, including async programming, API development, packaging, testing, and performance considerations.
• Strong experience with cloud infrastructure (esp. AWS and/or GCP), including compute, networking, containerisation, and scaling patterns.
• Knowledge of modern AI/ML execution patterns, including model inference runtimes, distributed inference, GPU workloads, and model serving.
• Familiarity with orchestration tools (e.g., Kubernetes, Ray, Prefect, Airflow) or similar distributed compute frameworks.
• Experience designing or contributing to SaaS architectures, including authentication, data pipelines, telemetry, and multi-tenant considerations.
• Understanding of media workflows, file formats, and performance considerations for media-heavy or interactive systems is advantageous.
• Experience integrating systems with native modules or C++ back-ends (via Python bindings, gRPC, REST, OMQ, Redis, etc.).

• Hands‐on experience with AI tooling such as diffusion models, LLMs, vector databases, model hubs, or graph-based AI systems (e.g., ComfyUI).
• Experience with hybrid compute architectures (local + cloud execution).
• Familiarity with Nuke / Nuke Studio or other VFX/CG/VFX pipeline components.

Job Responsibilities

• Software & System Development

• Design, build, and maintain Reactor's cloud and local execution services, including AI model orchestration, job scheduling, data pipelines, and hybrid compute workflows.
• Implement APIs, services, and infrastructure that support rapid prototyping while laying the foundations for a scalable product that can be deployed across on‐prem, private cloud, and public cloud.
• Develop Python‐based orchestration layers for AI inference (LLMs, diffusion models, vision models) as well as lightweight training and fine‐tuning workflows (e.g., LoRAs).
• Ensure systems support fast feedback cycles for front‐end interactions (node graph, timeline, interactive AI tools).
• Build telemetry, observability, and monitoring systems that support iterative learning and production readiness.

• Devise pragmatic solutions to complex technical challenges in distributed compute, AI execution, and media‐heavy workflows.
• Create prototypes and internal tools to de‐risk architectural choices and validate assumptions before committing to long‐term paths.
• Repurpose or integrate internal/external technologies where expedient, maintaining a strong sense of pragmatism and efficiency.
• Surface hidden constraints in product or workflow designs and help guide the team to workable alternatives.

• Translate high‐level product goals into clear engineering tasks, architectural plans, and system designs.
• Flag architectural risks and early technical one‐way‐door decisions, proposing reversible solutions or low‐cost experiments to gather evidence.
• Contribute to planning, estimation, and prioritisation in a fast‐paced, discovery‐driven environment.
• Collaborate closely with front‐end engineers to shape the contracts, APIs, and execution patterns required for responsive UX.
• Contributes to discovery sessions, prototype reviews, and production partner workflows to understand technical requirements from real use cases.
• Work with the Lead Engineer, Nuke team, Research Team, and other Foundry groups to integrate or leverage existing technology where appropriate.
• Share knowledge openly across the team, contributing to a culture of transparency, exploration, and continuous learning.

THE COMPANY

Foundry has a heritage of more than 25 years, developing creative software for the Media and Entertainment industry. Its portfolio of award‐winning products solves complex visualization challenges to turn incredible ideas into reality. Working with creative leaders around the globe, Foundry products are used to create breathtaking visual effects and animation and have been integral in the making of every VFX Academy Award‐winning film for the past decade.

For more information visit www.foundry.com.