Software Engineer, AI/LLM

Company Description

Sellence is building cutting-edge sales CRM engines designed to deliver personalized customer experiences for B2C brands. We aim to significantly increase conversion rates and return on ad spend (ROAS) through intelligent automation.

We are hiring a full-time Software Engineer with strong Python and LLM experience to join our Tel Aviv-based team (hybrid with remote flexibility). In this role, you will be a core architect of our product, responsible for designing, building, and scaling the AI engine that powers our agentic B2C sales CRM. You will create the robust, high-performance systems that enable our AI agents to conduct intelligent, human-like sales conversations, directly impacting our clients' success and our company's growth.

• Backend Development: Develop, test, and deploy production-grade backend services and APIs that integrate seamlessly with Large Language Models (LLMs).
• AI Orchestration: Engineer and refine complex prompt chains, agentic workflows, and function-calling logic within a scalable software architecture.
• RAG Architecture: Architect and implement robust Retrieval-Augmented Generation (RAG) systems using vector databases such as PostgresML.
• Data & Evaluation: Build and maintain data pipelines and evaluation frameworks to rigorously test and improve our AI models and prompt strategies.
• Database Design: Design and optimize database schemas and write complex queries to support our AI systems and analytics needs.
• Collaboration: Work closely with product and data science teams to translate business requirements into elegant technical solutions.

• 3+ years of professional software engineering experience with expert-level proficiency in Python.
• Proven experience building and deploying scalable, production-grade backend services using FastAPI on a Linux environment.
• Strong proficiency in SQL is a must, with experience writing complex queries and working with relational databases.
• Deep hands-on experience with LLM APIs (e.g., OpenAI, Anthropic, Gemini) and a strong understanding of advanced prompt engineering principles.
• Practical experience designing and implementing solutions with vector databases such as Weaviate or PostgresML.
• Familiarity with asynchronous programming (Asyncio) and performance optimization.
• Strong problem-solving, analytical, and system design skills.
• Bachelor’s degree in Computer Science, Engineering, or a related field.
• MSc in a relevant field is a strong plus.