Who are Composal's investors?

Composal's investors include Y Combinator.

Where is Composal headquartered?

Composal is headquartered in London, GB.

Composal

YC F26

London, GB · Founded 2026 · 3 employees · 1 known investors

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Composal runs swarms of AI agents that interact with a product the way real users would, testing actual flows and edge cases to surface bugs and gaps before a release. It is a software testing tool for product and engineering teams evaluating whether features are ready to ship.

Also known as Vex · VEX

AI & Machine Learning Developer Tools Enterprise Software Artificial Intelligence DevSecOps Cloud ComputingUnited KingdomEurope

Founders & leadership· Y Combinator alumni (F26)

Pandelis Zembashis Founder/CEOPreviously CTO at Cosine, where he built AI coding agents and their supporting infrastructure, including a CLI harness, sandboxed execution, and large-scale repository mirroring for data generation and model training. He is co-founder and CEO of Composal, which uses agents to test software and surface bugs before release.

Jonathan Davies Founder/CTOHe was previously a senior software engineer at PapayaDash and has built software for Telefonica, Mitie, and Vodafone.

Jan Hendrik MoehlmannFounderFounder of Composal (composal.ai, YC F26). Previously held commercial roles at 11x, Encord, and Tractable.

Investors · 1

Y Combinatorlisted by Y CombinatorSan Francisco · $500K

How we know: the Y Combinator directory · Not right? Tell us

Images

Companies House · registry record

View on Companies House ↗

Registered name: COMPOSAL LTD
Company number: 15535753
Status: Active
Company type: Private limited company
Incorporated: 2 Mar 2024
Registered office: 86-90 Paul Street, London, EC2A 4NE
Nature of business (SIC): 62012 — Business and domestic software development70229 — Management consultancy activities other than financial management
Accounts: last made up to 31 Mar 2026 · next due 31 Dec 2027
Confirmation statement: last made up to 1 Mar 2026 · next due 15 Mar 2027

Current officers · 1

Che Asha Blagrove-Stacey — director, appointed 2 Mar 2024

Source: Companies House public register · retrieved 11 Oct 2026. Contains public sector information licensed under the Open Government Licence v3.0.

Frequently asked questions

What does Composal do?: Composal runs swarms of AI agents that interact with a product the way real users would, testing actual flows and edge cases to surface bugs and gaps before a release. It is a software testing tool for product and engineering teams evaluating whether features are ready to ship.
Who are Composal's investors?: Composal's investors include Y Combinator.
Where is Composal headquartered?: Composal is headquartered in London, GB.