Summary: Join a small, highly collaborative team as a Senior Software Engineer, designing and implementing backend and frontend features, with a strong focus on AI-powered solutions. Highlights: 1. Work on complex business logic and build real AI features, not just demos. 2. Small team, high ownership, low bureaucracy, and real product impact. 3. Opportunity to contribute to architecture and technical decisions. DESCRIPTION Barcelona (Hybrid) 4 days in\-office, 1 day remote Full\-time Remuner, a fast\-growing B2B SaaS company in the RevOps tech space **About Remuner** We are a fast\-growing B2B SaaS company based in Barcelona, building a data\-driven platform that helps companies automate and optimize complex business processes. Our product deals with high volumes of data, non\-trivial business logic, and increasingly incorporates AI\-driven capabilities to assist users and automate workflows. **What You’ll Do** We’re looking for a senior engineer who goes beyond just shipping features — someone who understands the business behind the product, challenges requirements, and builds solutions that actually solve problems. You will be part of a small, highly collaborative team with strong ownership and direct impact on the product. * Design and implement backend systems and APIs (Python, FastAPI/Django) * Build and improve frontend features (Vue.js) * Work with data\-intensive systems and optimize performance (SQL/NoSQL) * Design and implement AI\-powered features and workflows * Work on orchestration of AI agents and integrations with LLMs * Contribute to architecture and technical decisions * Review code and uphold engineering standards * Collaborate closely with product and business stakeholders * Translate business problems into technical solutions * Take ownership beyond implementation, understanding impact and trade\-offs * Own features end\-to\-end: from design to deployment and monitoring **You’ll enjoy this role if** * You like working on complex business logic, not just CRUD * You’re comfortable dealing with messy real\-world data * You care about performance, scalability, and clean systems * You’re excited about building real AI features, not demos * You naturally think in terms of problems, not tickets * You want to understand why things are built, not just how **How we work** * Small team, high ownership, low bureaucracy and real impact on the product * Pragmatic engineering culture (we optimize for impact, not over\-engineering) * Direct exposure to product decisions and customers **What we offer** * **Hybrid Work Policy** – Fridays from 9:00–15:00 remote, plus six additional remote days per quarter. * **Flexible Working Hours** – Shape your schedule with manager's approval to match your productivity. * **AI\-Native Culture** – Opportunity to work on real AI problems (not just demos) * **Growth opportunities** as the company scales internationally * **Young, dynamic, and multicultural team** * **Office Comforts** – Fresh fruit, coffee, and snacks to keep you fueled. * **Free Lunch** – From Monday to Thursday enjoy free in\-office lunch catering * **Flexible Compensation** – Tax\-advantaged spending on transport, restaurants, bars, kindergarten services, plus private health insurance options. REQUIREMENTS **What We’re Looking For** **Must\-have** * 5\+ years of experience as a Software Engineer * Strong experience with **Python** * Experience with **FastAPI and/or Django** * Solid experience with **JavaScript and Vue.js** * Strong understanding of **SQL databases** and query optimization * Experience building production\-grade APIs * Hands\-on experience building **AI\-powered features** (LLMs, embeddings, etc.) * Experience orchestrating **AI agents or multi\-step AI workflows** (LangChain, LangGraph, or similar) * Strong knowledge of agentic AI workflows (**Claude**, **Codex**, etc.), with demonstrated curiosity and continuous learning about the rapidly evolving AI landscape * Strong product mindset: ability to understand business problems and propose solutions, not just execute tasks * Ability to work with ambiguity and think end\-to\-end across systems * Fluent in English **Nice to have** * Experience with **AWS (ECS, S3, RDS, etc.)** * Experience with **data pipelines or ETL systems** * Frontend performance optimization experience * Familiarity with CI/CD and modern deployment workflows * Experience in B2B SaaS environments