Callosum
callosum.com
Actively hiring
As featured in
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Overview
News
Technologies
Salaries
Products
People
Growth
Offices
Jobs
Financials
Funding and backers
Total raised
$100M
1 round on record
Latest round
$100M
Seed · Aug 2026 · 1 mo ago
Team
11-50
employees, estimated range
Hiring now
10
open roles
Backers
2
Albion, Norrsken
The money's age
Fresh money
1 months since the last round · hiring slowed
Momentum
35/100
in the news, fresh money
Last sign of life
this month
a posting or a news item
The story so fareach stage dated by its source: the company's releases, the press, registers, filings
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
Albion 
Norrsken Similar startupsby what they do, their industry and backers
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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
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.
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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
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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
36
Postings analysed
16
Stack modernity
73/100AI adopter
Languages
Python25%
C++13%
Erlang6%
Rust6%
Frameworks & libraries
CUDA13%
PyTorch13%
SGLang13%
JAX6%
Cloud & platforms
Cerebras100%
CUDA Toolkit13%
vLLM13%
Apache Kafka6%
AI & ML
LLM19%
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Full Callosum tech stack
36 technologies · by team · pay by technology · changes · similar stacks
Salary insights
Compensation ranges based on this company's open jobs
Median
$254k
Typical range
$254k
Open positions
9
9
Jobs
Staff
100%
| Level | Jobs | Median | Typical range |
|---|---|---|---|
| Staff | 9 | $254k | $254k |
Highest paying role
Accelerator Systems Software - Member of Technical Staff
$254k
Normalized to USD per year
Growth
Hiring Momentum
29/100
Slowing
Open positions
10
0 opened / 6 closed in 30 days
Median time-to-fill
97 days
faster than 17% of the market
ATS activity
Every ~9 hours
Today
Hiring Dynamics
0%
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
Added Rest API to stack
Sep 2026
Added Machine Learning to stack
Sep 2026
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 $254k Avg Salary
hires for AI/ML
Jobs
≈ $115k – $229k per year (Estimated) • In office • Full-Time • London
AI Agents
Cerebras
Apply
$134k – $255k per year • In office • Full-Time • London
Function Calling
AI Agents
Cerebras
Tool Use
Machine Learning
Apply
$134k – $255k per year • In office • Full-Time • London
Python
Rust
C++
Erlang
TensorFlow C++
PyTorch C++
Databases
Apache Kafka
AI/ML
JAX
TensorFlow
PyTorch
Ray
Cerebras
Apply
$134k – $255k per year • In office • Full-Time • London
vLLM
Function Calling
AI Agents
SGLang
Cerebras
Post-training
LLM Evaluation
Multi-Agent Systems
Tool Use
Apply
$134k – $255k per year • In office • Full-Time • London
LLM
Cerebras
Machine Learning
Apply
$134k – $255k per year • In office • Full-Time • PhD • London
Python
Function Calling
AI Agents
LLM
Cerebras
Tool Use
Machine Learning
Apply
$134k – $255k per year • In office • Full-Time • London
Cerebras
KV Cache
Apply
$134k – $255k per year • In office • Full-Time • London
Triton Inference Server
Cerebras
Apply
$134k – $255k per year • In office • Full-Time • London
Python
C++
vLLM
CUDA Toolkit
SGLang
Cerebras
CUDA
Apply
$134k – $255k per year • In office • Full-Time • London
CUDA Toolkit
Cerebras
CUDA
ROCm
MLIR
Apply
Financials
Total raised
$100M
Latest round
Seed
Funding rounds
1
Funding rounds
| Round | Announced | Amount | |
|---|---|---|---|
| Seed | 2026 | $100M | Details |