Skill needed: OWL, SHACL, RDF, Neo4j, Knowledge Graph.
Employer: Cala AI
About Cala AIFrom the creators of Vilynx - a Barcelona AI startup acquired by Apple - comes Cala AI: a bold new venture redefining how information is verified and represented at massive scale. Based in Barcelona’s vibrant tech hub near Passeig de Gràcia, Cala AI is building innovative AI systems focused on trust, accuracy, and impactful technology that challenges industry norms.Recently, Cala AI was named by Creandum to their #EuroSeed50 list - highlighting the most promising early-stage startups in Europe - an honor that reflects the strong belief in our mission and team. We are a small, ambitious group dedicated to building real solutions with grit, heart, and a culture of authenticity.About the roleWe’re looking for a Data Engineer specialized in Knowledge Graphs to join our growing team. You’ll work at the intersection of big data, semantics, and AI, helping architect and scale our graph-based data infrastructure.Your role will focus on designing and maintaining data systems that power our knowledge graph platform - including RDF graphs, ontologies, and semantic validation/querying pipelines. You'll contribute to a deeply technical mission: representing and verifying information in a structured, trustworthy way.What you’ll doDesign, build, and maintain scalable graph-based data pipelines (batch and streaming)Model and manage RDF/semantic graphs using ontologies (OWL), SHACL, and SPARQLIntegrate with property graph systems (e.g. Cypher for Neo4j or similar)Explore and work with graph databases such as Neo4j, JanusGraph, or Amazon NeptuneCollaborate closely with the Data and AI teams on data modeling, storage, and transformationHelp shape the representation layer of AI-driven systems using semantic technologiesPromote a culture of clean, reliable, and meaningful data engineeringWhat we’re looking for1+ years of hands-on experience with Knowledge Graphs or Semantic Web technologiesBackground in Data Engineering or Data Science (engineering preferred)Experience with RDF, OWL, SHACL, and SPARQLKnowledge of property graphs (Cypher) and graph DBs (Neo4j, JanusGraph, etc.)Proficiency with general data engineering tools (e.g. Python, SQL, Spark, Kafka)Familiarity with AWS Neptune or similar managed graph solutions is a plusLanguage: B2+ in either English or SpanishCurious, collaborative, and excited to tackle a specialized, high-impact challengeWhy join Cala AI?Work alongside a founder with a proven track record in AI startupsJoin a company dedicated to building AI for good - focused on trust and impactCompetitive compensation package plus stock optionsBased in Cloudworks, a dynamic co-working space near Passeig de Gràcia in Barcelona; enjoy the perks that come from being part of Cloudworks, like gym subscription and restaurant discountsA supportive, inclusive, and horizontal culture that values authenticity and growthHiring Process (Conversation-Based)Intro chat with CTO (projects & motivation)System design interview (onsite preferred)Cultural fit chat with CEOOfferWe welcome applicants from diverse backgrounds who bring passion, curiosity, and resilience. If this sounds like you, get in touch — we’re excited to see what we can build together.