Mid/Senior AI LLM Engineer (Full Remote - Europe)

This a Full Remote job, the offer is available from: Europe Our Vision & Products🚀 EverAI — Building the Future of AI Companionship One of the Top 15 Largest & Fastest-Growing AI Companies in the World 50 Million Users in 2 years — Help Us Reach 100M first, 500M next At EverAI, we're shaping what it means to connect with AI. With 50 million users and counting, we're not just building products — we're creating entirely new categories. Our flagship product is the world's largest AI companionship platform, redefining relationships for millions. It is governed by our proprietary moderation system, EverGuard — an internal AI designed to ensure everything we build is safe, ethical, and human-first. And we're only just getting started! Our TeamWe are an enthusiastic, passionate and hardworking team of ≈ 100 people. Our founding team has strong entrepreneurial experience building and scaling web products from 0 to IPO. Alexis Soulopoulos [CEO] • 10+ years in Tech Executive Leadership • Co-Founder Mad Paws Holdings (from 0 to IPO) • Forbes 30 under 30 + Deloitte TechFast50 '22 & '23 Michael Monin [Co-founder & CTO] • 10+ years as CTO / COO (web2/web3), 3 years in AI/LLM • Serial-entrepreneur: MTK Digital (exited / 0->$20m revenue) and Zipchat (AI Chatbot for E-commerce brands) Thomas Lacroix [Co-founder & CMO] • 8+ years in Customer Acquisition & E-commerce Growth • Serial-entrepreneur: Curatible (sold to Blackstone) and MTK Digital (exited / 0->$20m revenue) Maruša Fasano [CFO/Legal] • 25+ years in Finance, Strategy, M&A • Ex-CFO/M&A @Curatible (exited to Blackstone) • Ex-President of the Board @SotremoSA (exited) • Co-founder/CFO @SoftOne (exited) Your RoleMost LLM roles stop at experimentation. Here, the models you improve power experiences for 50M+ users. Most of our traffic runs on self-hosted, fine-tuned open-weight models. On our internal roleplay evals, our smaller fine-tuned models can outperform much larger off-the-shelf models. Your job is to make them better. You'll join a small AI team led by Marco, our LLM Tech Lead, working closely with our CTO, Product, Web and DevOps teams. You'll work across data, post-training, evals, and model behavior, taking ideas from failure analysis to production. The problems are real: personalization, character consistency, long conversations, better evals, multilingual behavior, and faster training cycles. If you want to shape model behavior at consumer scale, this is the role. Key ResponsibilitiesFine-tune open-weight LLMs using SFT, LoRA/QLoRA and post-training methods such as DPO and GRPO Diagnose model failures and turn them into experiments. Decide whether the answer is better data, post-training, prompting or classifiers Build training data and evals that directly shape what gets trained next Improve model behavior across personalization, consistency, tone, multilingual and group interactions Ship to production and use real user behavior to guide the next iteration Speed up the training loop so experiments are faster, easier to compare, and more reproducible Your QualificationsYou've personally post-trained open-weight LLMs for a user-facing product and shipped them to production You've worked where AI was core to the product or business, not an experimental side feature Fine-tuning is core to your experience Strong Python, PyTorch and Hugging Face, with hands-on GPU training and debugging You build data and evals yourself and make decisions from evidence You can take work beyond notebooks into production You use AI tools daily in your own engineering work You are fully comfortable working with uncensored models and explicit NSFW content, including harmful material when developing and evaluating moderation system Bonus pointsExperience with conversational AI, roleplay products, or highly personalized consumer AI Multilingual LLMs Moderation, safety, or adversarial testing Multimodal models Open-source LLM / post-training contributions Why EverAI?📈 Exponential Growth: From 50M users in 2 years, to 100M next — and 500M beyond 🚀 Track Record of Category-Creating Innovation: We consistently launch world-first AI applications — setting the pace, not following it 🌍 Global Impact: Top-tier user growth, real-world adoption, and cultural relevance 🧠 Proven Leadership: A senior team that's launched, scaled, and exited & IPO'd multiple scale ups — now fully focused on reshaping AI companionship 👥 Elite Remote Team: 100% remote and built to win — world-class talent from Tier 1 tech companies, with a culture of ownership, velocity, and radical creativity 🛡️ Ethical Core: Our AI ecosystem is governed by EverGuard, our proprietary AI moderation technology, ensuring responsible development at scale What We Offer✍️ Contract Type: We prefer B2B, but we're flexible, what matters is long-term commitment and impact 📍 Work From Anywhere: Fully remote. Choose the environment where you do your best work 🏝️ Paid Time Off: 4