Callosum logo
Callosum logo
Callosum
callosum.com
callosum.com • HQ: London, United Kingdom • 11-50 employees • Founded 2024 • Startup
HQ: London, United Kingdom • 11-50 employees • Founded 2024 • Startup
Actively hiring
AI Compute & Inference
AI Chips & Accelerators
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Back to the profile Callosum Tech stack 34 technologies

What jobs is Callosum hiring for right now?

As of Oct 21, 2026, Callosum has 10 open jobs on Alion. They are posted in one city. Its postings score A on the Alion truth index.

Source: Alion Coverage: open vacancies from the employer's own careers board Oct 19, 2026
Open jobs
10
Cities
1
Median age
60 days

How Callosum hires

Truth index
A 95/100
Median time to fill
100 days
Ghost roles
0%
Stale roles
0%
Reposted roles
0%

Callosum scores A on the Alion truth index (A is best, E worst), measured over 3 open roles re-checked against its own hiring board: 0% look like ghost listings, 0% have gone stale and 0% are the same role posted again. Its roles close in a median of 100 days. It measures how much of what this employer publishes turns into a real, finite search - not the employer as a workplace. How the index is computed

Where Callosum is hiring

How the work at Callosum is set up

Work format
In office 10 100%
Level
Staff+ 9 90%
Lead 1 10%
Employment
Full-Time 10 100%

Open vacancies at Callosum

≈ $114k – $210k per year (Estimated) • In office • Full-Time • London
AI Agents
Cerebras
Apply
≈ $149k – $286k per year (Estimated) • In office • Full-Time • London
Function Calling
AI Agents
Cerebras
Machine Learning
Apply
≈ $147k – $283k per year (Estimated) • In office • Full-Time • London
Python
Rust
C++
Erlang
TensorFlow C++
Databases
Apache Kafka
AI/ML
JAX
TensorFlow
PyTorch
Ray
Cerebras
Apply
≈ $153k – $295k per year (Estimated) • In office • Full-Time • London
vLLM
Function Calling
AI Agents
SGLang
Cerebras
Post-training
LLM Evaluation
Multi-Agent Systems
Apply
≈ $148k – $285k per year (Estimated) • In office • Full-Time • London
LLM
Cerebras
Machine Learning
Apply
≈ $148k – $284k per year (Estimated) • In office • Full-Time • PhD • London
Python
Function Calling
LLM
Cerebras
Machine Learning
Apply
≈ $164k – $315k per year (Estimated) • In office • Full-Time • London
Cerebras
KV Cache
Apply
≈ $144k – $277k per year (Estimated) • In office • Full-Time • London
Triton Inference Server
Cerebras
Apply
≈ $150k – $289k per year (Estimated) • In office • Full-Time • London
Python
C++
vLLM
SGLang
Cerebras
CUDA
Apply
≈ $153k – $294k per year (Estimated) • In office • Full-Time • London
Cerebras
CUDA
ROCm
MLIR
Apply

Questions about jobs at Callosum

Is Callosum hiring right now?

Yes. As of Oct 21, 2026, Callosum has 10 open jobs on Alion.

What roles does Callosum hire for?

Callosum is hiring mostly for AI/ML. The largest group is AI/ML with 10 open vacancies.

Where does Callosum hire?

Callosum has open vacancies in 1 places, most of all in London.

How long have Callosum vacancies been open?

Half have been on Alion for 60 days or less. 3 vacancies at Callosum have been listed for more than 90 days, and postings of that age are far more often out of date.

How reliable are Callosum job postings?

Callosum scores A on the Alion truth index (A is best, E worst), measured over 3 open roles re-checked against its own hiring board: 0% look like ghost listings, 0% have gone stale and 0% are the same role posted again. Its roles close in a median of 100 days.

How do you apply to Callosum?

Callosum accepts applications through Ashby, so the form opens on that system rather than on Alion.

How to cite this page

These figures are published under a free licence. You may reuse them, including commercially, as long as you credit Alion and link back to this page.

Alion, "Callosum: 10 open jobs", as of Oct 21, 2026. https://alion.io/company/callosum/jobs

Licence: CC BY-SA 4.0Map: OpenFreeMap, OpenStreetMap. City coordinates: GeoNames (CC BY 4.0)