COMPANY PROFILE

Mantle8

Natural hydrogen exploration using proprietary geophysical and geochemical technologies for sustainable energy solutions

Sassenage, FranceFounded 2019Energy

Valuation $100–250M Last recorded · 2026

Headcount <100 Current team size

Total funding $10–50M Disclosed equity funding

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About Mantle8

Mantle8 is a Grenoble-based natural hydrogen exploration company that uses proprietary geophysical and geochemical methods to locate and validate high-purity geologic hydrogen reservoirs for clean energy. In May 2026 Mantle8 raised a €31 million Series A led by Sandwater, with Breakthrough Energy Ventures, Bpifrance Ecotechnologies 2, IP Group, Wind Capital and Calderion, bringing total funding to about €37 million to fund a multi-year global exploration and drilling campaign proving commercial viability. Sources: company May 2026; FinSMEs; Startup.eu.

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At a glance

Status: Operational
Founded: 2019
Headquarters: Sassenage, France
Employees: 32
Open positions: 13
Dealroom signal: 91.7/100
Industry: Energy
Sub-industry: Clean Energy
Sector: Energy, Mining Technologies, Hydrogen, Sustainable Development Goals, Climate Tech, Energy and Greentech, Observatoire Deeptech, White Hydrogen, observatoire greentech, observatoire industrial tech, out of stealth
Business model: Manufacturing
Client focus: b2b
Links: Website LinkedIn

Knowledge graph

Founder mafia, market maps, research and news connected to this company by Dealroom

Open roles

2 open roles

Research Engineer – Seismology & Full Waveform InversionData & AI · Toulouse, France · 3w ago Corporate ControllerFinance & Legal · Grenoble, France · 1mo ago

From job postings in the last four months. Careers page ↗More startups hiring →

Funding history

4 recorded events

Company financing events and reported valuations.

Deal type	Date	Amount	Valuation	Investors	Source
SERIES A✓Equity / VC	May 2026	$34M	$136M	Breakthrough Energy Ventures · Sandwater · Calderion · Bpifrance	↗
GRANT✓Other financing	Mar 2026	$2.3M	—	European Commission	↗

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Growth signals

Mantle8 website traffic

Latest recorded traffic for Mantle8 is 7.2K monthly website visits, up 278.9% over the last three months. Mantle8's team grew 357.1% over the past year.

Latest monthly visits7.2K 3-month web change+278.9% 1-year team growth+357.1%

Monthly website visitsFeb 2025–Jul 2026

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Open positions

Openings linked to this company in Dealroom

Geo-Environmental & Permitting ApprenticeToulouse, Occitanie, France · Other · Jul 6, 2026 IP CounselGrenoble, Auvergne-Rhône-Alpes, France · Legal · Jul 5, 2026 Assistant RH/Assistante RHGrenoble, Auvergne-Rhône-Alpes, France · Other · Jun 28, 2026

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OHOui HydrogenFocusing on the 'on demand hydrogen and heat production' using hydrolysis reactions	Lyon, France	Operational
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INInocelAn industrial company that offers end-to-end hydrogen energy chain solutions with innovative fuel cells	Saint-Égrève, France	Operational
SASAKOWINOn-site production of decarbonized hydrogen through methane plasmalysis with negative or neutral in CO2 emissions and 5 times less electricity than electrolysis	Aix-en-Provence, France	Operational
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