Senior Software Engineer – AI Hub

OfficeRnD

Senior Software Engineer designing and building backend architecture for AI Hub at OfficeRnD. Enhancing autonomous agents' performance and ensuring backend system integrity in a hybrid work environment.

Posted 5/31/2026full-timeSofia • 🇧🇬 BulgariaSeniorWebsite

Tech Stack

Tools & technologies

CloudDistributed SystemsJavaJavaScriptMongoDB.NETNode.js

About the role

Key responsibilities & impact

Design, build, and scale the backend architecture and APIs powering the AI Hub and its autonomous agents (like the AI Sales Agent).
Implement robust, low-latency integrations between core backend systems, LLMs, and communication channels to support 24/7 real-time automation.
Ensure consistency, performance, and correctness across high-volume data models and complex backend workflows.
Own MongoDB schema design and query optimization for complex data structures (including data models optimized for AI context and conversation history).
Collaborate closely with Product Managers, Software Architects, and AI specialists to translate advanced automation requirements into robust technical solutions.
Own and lead backend-focused strategic initiatives and architectural improvements within the AI Hub ecosystem.
Own and lead frontend-focused strategic initiatives and architectural improvements within the AI Hub ecosystem.
Debug and resolve production issues across the backend stack and infrastructure layer.
Review peer code with a focus on correctness, performance, and maintainability.
Write unit and integration tests and functional tests; Mentor junior engineers on backend fundamentals, system design, and AI integration best practices.

Requirements

What you’ll need

5+ years of backend engineering experience in cloud-based, production environments.
Proficiency in at least one server-side technology (Node.js, Java, or .NET).
Hands-on experience integrating LLMs or building AI-driven features in production - and genuine curiosity about where autonomous agents are heading.
Experience designing AI agent architectures - tool/function calling, multi-step reasoning, memory/context management, and observability.
Strong foundation in API design, distributed systems, and real-time data processing.
Experience with MongoDB schema design and query optimization; familiarity with vector DBs or caching strategies for AI is a plus.
Extensive knowledge of software design principles - you default to clean architecture, separation of concerns, and domain modelling.

Benefits

Comp & perks

Premium health insurance, including dental coverage
25 days of annual paid leave
An additional day off to celebrate your birthday
3 paid volunteering days per year
Full compensation for the first 3 days of sick leave
Hybrid work model (minimum 40% of monthly working time onsite)
Co-funded sports card to support your active lifestyle
Excellent learning and development opportunities, including access to courses, tools, and internal workshops focused on AI and modern engineering.
Parking access or public transport pass

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Hard Skills & Tools

backend engineeringNode.jsJava.NETAPI designdistributed systemsreal-time data processingMongoDB schema designquery optimizationAI agent architectures

Soft Skills

collaborationmentorshipproblem-solvingleadershipcommunication