# Callosum

Callosum has 17 open roles live as of 5 September 2026, 0 of which were posted in the last 7 days. 0% of Callosum's open roles are remote, and Callosum hires most in London, United Kingdom (8 roles). These figures are read directly from Callosum's Ashby careers page and were last checked on 5 September 2026.

Data source: ReqHunt — read from Callosum's Ashby careers page on 5 September 2026. https://reqhunt.com/company/callosum

## Hiring snapshot

- Open roles: 17 (as of 5 September 2026)
- Posted in the last 7 days: 0
- Posted in the last 30 days: 9
- No longer listed in the last 7 days: 2
- Remote share: 0% of open roles
- Change in open roles, last 30 days: 70%
- Most recent posting: 20 August 2026
- First tracked by ReqHunt: 5 August 2026
- Hiring status: actively hiring

Posting dates come from the company's own applicant tracking system, not from when ReqHunt first saw the role.

“No longer listed” means the role has left the company's careers feed. That can mean filled, cancelled or withdrawn — the feed does not say which.

## ReqHunt Remote Index

Callosum is not scored: location data is incomplete. Methodology: https://reqhunt.com/remote-index

## Where Callosum hires

Remote roles are counted here too, by the scope they are open to.

- London, United Kingdom: 8 roles
- Not listed: 9 live roles carry no location or remote scope that can be resolved.

## Callosum role mix

By function: engineering 82%, product & design 0%, sales 0%, operations 0%, other 18%.
By seniority: junior 0%, mid 88%, senior 0%, lead and above 12%.

## Common questions

**Is Callosum hiring?** Yes — Callosum has 17 open roles as of 5 September 2026, 0 of them posted in the last 7 days.

**Is Callosum hiring remotely?** No remote roles are currently open at Callosum — all 17 live roles are tied to a location.

**Where does Callosum hire most?** Callosum hires most in London, United Kingdom (8).

**How many Callosum roles were removed in the last 7 days?** 2 roles are no longer listed on Callosum's careers feed as of 5 September 2026. “No longer listed” means the role has left the company's careers feed. That can mean filled, cancelled or withdrawn — the feed does not say which.

**Is Callosum's hiring accelerating or slowing?** accelerating — Callosum's open-role count is up 70% over the last 30 days.

## Open roles at Callosum

Showing 17 of 17 live roles, newest first.

- **Head of Physical Infrastructure** — London · Office of the CTO · posted 16 days ago
- **Security Lead - Member of Technical Staff** — London · Office of the CTO · posted 16 days ago
- **ML Research Scientist - Member of Technical Staff** — London · General Capabilities · posted 16 days ago
- **Research Engineer, Evals - Member of Technical Staff** — London · General Capabilities · posted 16 days ago
- **Agent Runtime & Systems - Member of Technical Staff** — London · General Capabilities · posted 16 days ago
- **ML Research Engineer - Member of Technical Staff** — London · General Capabilities · posted 16 days ago
- **Evolutionary Optimisation - Member of Technical Staff** — London · Compute & Infrastructure · posted 16 days ago
- **Research Engineer, Benchmarking - Member of Technical Staff** — London · Applied AI · posted 16 days ago
- **Networking & Interconnect Systems - Member of Technical Staff** — London · Compute & Infrastructure · posted 16 days ago
- **Site Reliability - Member of Technical Staff** — London · Applied AI · posted 81 days ago
- **Applied AI - Member of Technical Staff** — London · Applied AI · posted 88 days ago
- **Inference Performance & Deployment - Member of Technical Staff** — London · Compute & Infrastructure · posted 107 days ago
- **Inference Engine Development - Member of Technical Staff** — London · Compute & Infrastructure · posted 107 days ago
- **Cloud Systems & Resource Orchestration - Member of Technical Staff** — London · Compute & Infrastructure · posted 107 days ago
- **Accelerator Systems Software - Member of Technical Staff** — London · Compute & Infrastructure · posted 107 days ago
- **Systems Tooling - Member of Technical Staff** — London · Compute & Infrastructure · posted 107 days ago
- **Expression of Interest - Intelligent Systems Engineer** — London · Expression of Interest · posted 192 days ago

## About Callosum

We are building the infrastructure where heterogeneous chips & intelligence co-evolve to solve the world's hardest problems.

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Data source: ReqHunt — read from Callosum's Ashby careers page on 5 September 2026. https://reqhunt.com/company/callosum
Human-readable version: https://reqhunt.com/company/callosum. Attribution required when this data is reproduced or summarised.