Sigma AI
Madrid-headquartered global AI training-data services company. Powers 4 of the 5 largest global tech giants across 600+ languages and dialects.
What is Sigma AI?
Sigma AI is a global AI training-data services company headquartered in Madrid, Spain. The firm collects, labels, and annotates training data for enterprise AI teams and frontier model developers, spanning speech, text, image, video, and multimodal formats. Sigma covers 600+ languages and dialects and claims accuracy up to 99.99% on structured annotation tasks. On the customer side the company works with 4 of the 5 largest global tech companies (the exact roster is under NDA but implied by public marketing). Co-founded and led by CEO Daniel Tapias, whose background includes 18+ years of research in speech recognition and natural language processing before starting the company. Co-founder Nuria Gomez Bermejo serves as CFO. Sigma is one of the older, more capital-disciplined players in AI data services (founded in the 2000s, well before the current LLM cycle), which shows up in a steady book of enterprise contracts and a relatively large permanent staff bench compared to newer venture-backed competitors.
Mission & values
Deliver the highest-quality human-in-the-loop training data at global scale so AI teams can build models that work as well in every language and culture as they do in English.
Qualifications
Sigma hires across two engagement paths. (1) Corporate roles (data operations, project management, linguistics, ML engineering, sales, customer success, and finance) are listed at careers.sigma.ai and are largely based in or aligned with the Madrid HQ or one of the European delivery hubs. Sigma runs hybrid work with regular in-office days for corporate teams. (2) Distributed contributor and annotator roles are recruited per project against specific language, domain, and country requirements. Contributor tracks skew heavily toward European and rarer-language coverage where Sigma has a competitive edge over the US-only annotation platforms. Applications for both tracks go through careers.sigma.ai; native-fluency verification is standard for language-specific work.
Leadership
Nuria Gomez Bermejo
Co-Founder & Chief Financial Officer
Co-founded Sigma AI alongside Daniel Tapias. Leads finance and operations across the group.
Hiring process
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1
Apply at careers.sigma.ai
Browse open roles and submit your application through the Sigma careers portal.
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2
Recruiter screen
Confirms language fluency, availability, country match, and role fit.
About 5 days
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3
Language or skills assessment
Annotator and linguist roles: language proficiency test plus a sample annotation task. Corporate roles: role-specific interview.
About 5 days
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4
Hiring manager interview
Deeper conversation with the Sigma manager who will own the role or project.
About 7 days
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5
Offer and onboarding
Contract, payment setup, and platform training for annotators. Corporate roles include a standard onboarding week.
About 5 days
Funding
Awards & recognition
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600+ languages and dialects covered · 2026
Sigma AI
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4 of the 5 largest global tech companies as customers · 2026
Sigma AI
Company information
- Industry: AI Training Data / Data Annotation Services
- Location: Madrid, Spain
- Company size: 201-1000
- Website: sigma.ai ↗
- LinkedIn: Company page ↗