Callosum
AI Compute & Inference · AI Chips & Accelerators
10open roles
$100Mlatest round · Seed · Aug 2026 · 2 mo ago
5backers · Sovereign AI, Albion
Atruth index, 95 of 100
Overview
Callosum is an intelligent systems company building infrastructure in which AI hardware and models co-evolve, aimed at the growing diversity of new models and chips. It hires technical staff for accelerator systems software, cloud systems and resource orchestration, inference engine development and inference performance and deployment. The company is headquartered in London, United Kingdom.
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
Funding and backers
Total raised
$100M
1 round on record
Latest round
$100M
Seed · Aug 2026 · 2 mo ago
Team
11-50
employees, estimated range
Hiring now
10
open roles
Backers
5
Sovereign AI, Albion
The money's age
Fresh money
2 months since the last round · hiring slowed
Momentum
35/100
in the news, fresh money
Last sign of life
1 mo ago
a posting or a news item
The story so fareach stage dated by its source: the company's releases, the press, registers, filings
Nov 10
Hiring paused no new role in 60 days after 16 in half a year
Aug 20
Raised a round Seed $100M · Silicon Republic
Nov 13, 2024
Founded per the company register
Tractionpublic signals, read monthly
Web presence
top 3%
of 133.2M domains by links, Common Crawl
Hacker News stories
1
best: 1 points
Funding rounds
| Round | Date | Amount | Investors | Source |
|---|---|---|---|---|
| Seed | Aug 2026 | $100M | — | Silicon Republic |
Registers and programsofficial lists and records that name the company
| Legal entity | CALLOSUM LTD | Companies House |
| Registered | 13 Nov 2024 |
Backed byfrom the funds' portfolios and accelerator catalogs
Investors in similar startupsfunds that back the companies most like this one
Similar startupsby what they do, their industry and backers
DensityAI is building inference hardware and systems for frontier AI models, aiming at the fastest inference solution on the market. It…
Elastix is an American AI infrastructure startup that develops technology for scalable, energy-efficient AI inference. It combines machine…
Moreh is a South Korean company founded in 2020 that builds a software platform for training and serving large models on non-Nvidia…
TensorX is an artificial intelligence infrastructure enterprise specializing in sovereign AI inference and privacy-first compute solutions…
Infinity builds inference for new silicon. Our research agent Ignition generates a full inference stack on any chip.
Building the infrastructure for frontier AI. $312M Series B. Why we're building the memory layer for inference.
Jobs
≈ $108k – $209k per year (Estimated) · In office · Full-Time · London
AI Agents
Cerebras
Apply
≈ $145k – $283k per year (Estimated) · In office · Full-Time · London
Function Calling
AI Agents
Cerebras
Machine Learning
Apply
≈ $145k – $282k 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
≈ $152k – $297k per year (Estimated) · In office · Full-Time · London
vLLM
Function Calling
AI Agents
SGLang
Cerebras
Post-training
LLM Evaluation
Multi-Agent Systems
Apply
≈ $146k – $284k per year (Estimated) · In office · Full-Time · London
LLM
Cerebras
Machine Learning
Apply
≈ $144k – $281k per year (Estimated) · In office · Full-Time · PhD · London
Python
Function Calling
LLM
Cerebras
Machine Learning
Apply
≈ $161k – $314k per year (Estimated) · In office · Full-Time · London
Cerebras
KV Cache
Apply
≈ $143k – $279k per year (Estimated) · In office · Full-Time · London
Triton Inference Server
Cerebras
Apply
≈ $149k – $290k per year (Estimated) · In office · Full-Time · London
Python
C++
vLLM
SGLang
Cerebras
CUDA
Apply
≈ $154k – $301k per year (Estimated) · In office · Full-Time · London
Cerebras
CUDA
ROCm
MLIR
Apply
Visa sponsorship
A-rated
Sponsor licence
Skilled Worker
Visa route
10
Open roles in United Kingdom
10
Adverts offering sponsorship in 24 months
In the register as Callosum (+1 more)
Other sponsors in the same field
SambaNova Systems 
Fractile 
NVIDIA 
Nebius
See 10 open roles Alert me
UK Home Office · checked Nov 12, 2026 · Visa details by country
Growth
Hiring Momentum
48/100
Stable
Open positions
10
0 opened / 0 closed in 30 days
Median time-to-fill
108 days
faster than 10% of the market
ATS activity
Every ~6 hours
Today
Hiring Dynamics
+100%
Hiring Focus
The percentage next to each role is its share of the company's job openings over the last 90 days; the arrow shows the shift versus the previous period.
AI/ML
89% ▼
Leadership
11% ▼
Activity Timeline
Removed Rest API from stack
Sep 2026
Added Rest API to stack
Sep 2026
Added Machine Learning to stack
Sep 2026
Financials
Total raised
$100M
Latest round
Seed
Funding rounds
1
Funding rounds
| Round | Announced | Amount | |
|---|---|---|---|
| Seed | 2026 | $100M | Details |
Tech stack
Technologies named in job postings at Callosum over the last 12 months, by layer, with the share of postings for each.
Technologies in use
33
Postings analysed
16
Stack modernity
73/100AI adopter
Languages
Python25%
C++13%
Erlang6%
Rust6%
Frameworks & libraries
CUDA13%
PyTorch13%
SGLang13%
JAX6%
Cloud & platforms
Cerebras100%
vLLM13%
Apache Kafka6%
Grafana6%
AI & ML
LLM19%
Sign in to see how your skills match this stack
Sign In
Full Callosum tech stack
33 technologies · by team · pay by technology · changes · similar stacks
Connections
List
Graph
Found in company registers, site code, DNS and hiring. Each connection shows how sure we are and the evidence, with its source and date.
Shared investors
Sovereign AIVia a fund
Earth Venture CapitalVia a fund
NorrskenVia a fund
AlbionVia a fund
DCVCVia a fund
Click a company to open it. Dashed lines are likely connections. The second step of the network is part of the Pro plan.
Owner
Same company
Same group
Likely
News
London-based Callosum raises €85.4 million in Atomico-led Seed round to unify AI models and chips
Callosum, a London-based startup building infrastructure to unify different AI models and chips, has raised €85.4 million ($100 million) in a Seed round to advance what it calls "heterogeneous intelligence". The round was led by Atomico, with significant
Read more
Report
Agenesis of the corpus callosum: genetic, developmental and functional aspects of connectivity
Agenesis of the corpus callosum (AgCC) shares anatomical and behavioural features with certain neurodevelopmental and psychiatric disorders. Providing insight into the developmental and molecular basis of AgCC, Lynn Paul and colleagues explain why AgCC ma
Read more
Report
What Is Agenesis of the Corpus Callosum?
Agenesis of the corpus callosum is a birth defect where part of the brain doesn't grow properly. Learn about the causes, symptoms, and treatment options for this condition today.
Read more
Report
Concussion alters how information is transmitted within the brain
Damage from concussion alters the way information is transmitted between the 2 halves of the brain, according to a new study.
Read more
Report
The mysterious corpus callosum
The corpus callosum links one side of our brain to the other. It's not essential for survival, but in some people it's missing or malformed, causing quite mild to extreme disabilities. The good news is that research is now revealing that it holds intrigui
Read more
Report
The mysterious corpus callosum
The corpus callosum links one side of our brain to the other. It's not essential for survival, but in some people it's missing or malformed, causing quite mild to extreme disabilities. The good news is that research is now revealing that it holds intrigui
Read more
Report
Report
Corpus Callosum: Function, Definition & Anatomy
The brain is divided into the right and left hemisphere, and the two halves are connected by the corpus callosum. Learn more.
Read more
Report
Show more news
Offices
Where the company hires and what each office is for
Cities
1
Hiring now
1
Countries
1
Busiest office
London
London
United Kingdom
HQ
10 open roles 9 posted in 90 days 100% engineering 10-50 est. staff
hires for AI/ML