Software Engineer AI - Paris Barcelona

Build the backend foundations for Spendesk’s AI-native experiences

Spendesk is looking for a Backend Software Engineer (IC3) to join our PDE (Product, Design & Engineering) organization and help shape the technical foundations of our next generation of AI-powered product experiences.

This is a hands-on role for an engineer who combines strong backend fundamentals with solid fluency in LLM-enabled systems. You will work on the technical foundations behind conversational and agentic experiences: backend services for context handling, orchestration, tool calling, and reliable interactions with LLMs and applicative systems.

About the role

As a Backend Software Engineer (IC3), you will help create the backend layer that supports agentic and conversational experiences for Spendesk end users.

Your scope will include services that:manage conversations and contextual state,support the ingestion and retrieval of rich content such as PDFs and images,integrate LLMs through AWS Bedrock with robust operational patterns,connect to MCP-compatible services and tools exposed by other squads,orchestrate multi-step workflows combining reasoning, tool usage, and product actions.

This is not just about integrating services’ features to an LLM. You will build production-grade services that need to be reliable, observable, secure, and designed for long-term extensibility. You will contribute to reusable patterns and collaborate with ML Engineers, Product Managers, Designers, and applicative squads to make these foundations useful across multiple AI use cases.

Our tech environment

You’ll operate in a modern engineering environment designed for both product delivery and AI integration:

Type Script Node .js for backend and banking applications

React on the frontend

PostgreSQL for data storage;
Redis, SQS, and Kafka for jobs, queues, and event streaming

Terraform to define infrastructure as code Kubernetes, Lambdas, and Step Functions to run our applicationsAWS as our cloud provider, including AWS Bedrock for LLM access

GitHub Actions for CIKey responsibilities

Backend services for AI-native experiences

You will:

Design, build, and operate backend services and APIs that power conversational and agentic AI features.

Implement the services needed for context management, tool invocation, rich content access, and multi-step orchestration.

Build robust patterns for integrating LLMs through AWS Bedrock, including retries, fallbacks, tracing, and cost-aware usage.

Ensure these services are designed for production from day one, with strong standards on reliability, maintainability, and security.

Architecture & transversal system design

You will:

Partner with the IC5 Staff Engineer to implement the architecture supporting AI-native product experiences.

Contribute to reusable service boundaries, contracts, and interfaces that can be adopted across squads.

Help define how applicative squads can expose MCP-compatible tools and capabilities to central AI services.

Translate high-level architectural direction into concrete technical implementations and scalable engineering patterns.

Hands-on delivery of complex systems

You will:

Own complex backend components end-to-end, from design and implementation to deployment and maintenance.

Contribute directly to proof-of-concepts and experiments, then harden the successful ones into reliable production services.

Review code, challenge design decisions, and raise the quality bar on backend engineering within the squad.

Bring pragmatism to delivery, balancing speed of experimentation with long-term platform quality.

Observability, performance & operational excellence

You will:

Instrument services with logs, tracing, and metrics to ensure strong production visibility and fast iteration.

Help define and uphold quality standards around latency, failure handling, cost efficiency, and resilience.

Contribute to a strong “you build it, you run it” culture, where backend engineers own what they ship in production.

Ensure AI-related services are built with secure coding and responsible data handling practices.

Cross-functional collaboration

You will:

Collaborate with Product Managers and Designers to turn AI product concepts into…