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Callosum

Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
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Company facts

Seed-stage
Founded
2024
Employees
16
Headquarters
UNITED KINGDOMUNITED KINGDOM
11 jobs
callosum
6 views 2 months ago

Security Lead - Member of Technical Staff

Open 45d On-siteUKLead Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

Security Lead responsible for designing and assuring security across Callosum's full-stack AI orchestration platform—APIs, orchestration software, agentic systems, and physical compute—while building and leading the security team.

Agentic AI AI API Cloud
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callosum
3 views 2 months ago

Research Engineer, Evals - Member of Technical Staff

Open 45d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

Research Engineer building benchmarks and evaluation suites for agentic AI systems—designing rigorous measures for multi-turn, tool-using LLMs, turning traces into structured evidence, and building evaluation/observability infrastructure the whole company relies on.

Agentic AI AI LLM Machine Learning Observability
101K – 192K £
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callosum
8 views 2 months ago

Agent Runtime & Systems - Member of Technical Staff

Open 45d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

Builds the runtime and programming model for long-running AI agents that run for weeks across distributed infrastructure, focusing on durability, observability, and secure tool execution.

AI API Api Design C++ Distributed Systems +10 skills
101K – 192K £
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callosum
7 views 2 months ago

ML Research Engineer - Member of Technical Staff

Open 45d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

ML Research Engineer at Callosum designing experiments to understand why agentic AI systems fail, building evaluation infrastructure, and publishing findings to improve heterogeneous model/hardware orchestration.

Agentic AI AI Distributed Systems LLM Observability +1 skills
101K – 192K £
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callosum
4 views 2 months ago

Evolutionary Optimisation - Member of Technical Staff

Open 45d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

Build and improve an LLM-guided evolutionary search system that iteratively generates, evaluates, and optimises programs across kernels, inference runtimes, and scheduling policies, working with optimisation and search algorithms at an AI infrastructure startup in London.

AI LLM Machine Learning
101K – 192K £
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callosum
5 views 2 months ago

Research Engineer, Benchmarking - Member of Technical Staff

Open 45d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

Build and own a unified benchmarking system for evaluating agentic and algorithmic LLM solutions at Callosum's London office, using Python, sandboxed execution, and distributed systems to produce reproducible, contamination-controlled evaluation results.

Agentic AI AI LLM Machine Learning Python
101K – 192K £
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callosum
3 views 2 months ago

Networking & Interconnect Systems - Member of Technical Staff

Open 45d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

Build the networking and interconnect systems that let heterogeneous AI accelerators communicate efficiently, spanning RDMA, programmable NICs, memory movement, and cluster fabric strategy at Callosum's London office.

AI Ethernet Networking
101K – 192K £
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callosum
4 views 5 months ago

Inference Performance & Deployment - Member of Technical Staff

Open 110d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

About Us We’re living through a Cambrian explosion of intelligence: new models and new chips, each specialised for different tasks, are arriving all at once. The result is a new era for AI, one of radical…

AI Cloud Networking Triton
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callosum
7 views 5 months ago

Inference Engine Development - Member of Technical Staff

Open 110d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

About Us We’re living through a Cambrian explosion of intelligence: new models and new chips, each specialised for different tasks, are arriving all at once. The result is a new era for AI, one of radical…

AI API C++ CUDA Machine Learning +2 skills
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callosum
6 views 5 months ago

Accelerator Systems Software - Member of Technical Staff

Open 110d On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

About Us We’re living through a Cambrian explosion of intelligence: new models and new chips, each specialised for different tasks, are arriving all at once. The result is a new era for AI, one of radical…

AI CUDA Firmware
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callosum
8 views 7 months ago

Expression of Interest - Intelligent Systems Engineer

Likely evergreen On-siteUK Licensed UK sponsor — This employer appears on the GOV.UK register of licensed sponsors for the Skilled Worker and related work routes. The licence belongs to the employer and is not a commitment to sponsor this role.
United Kingdom

About Us We’re living through a Cambrian explosion of intelligence: new models and new chips, each specialised for different tasks, are arriving all at once. The result is a new era for AI, one of radical…

AI Distributed Systems
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Apply

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