The English-language job board for Spain

Senior Fullstack Developer (PHP + Python + Vue/React) – AI Agents

On-site in València·Full-time·Added 8 months ago

This job was published 8 months ago

Sesame HR

72 open roles

Apply

Overview

Job details

Full-time
Per the ad.

Requirements

Have the right to work in Spain
Sesame HR doesn't mention sponsorship in the ad.
Work on-site in València
No relocation package mentioned.
Have 5+ years of experience
Senior-level role.

This job was automatically translated to English.

Requirements

What we're looking for

More than 5 years of experience in software development, focusing on complex systems in production.
Solid experience in AI application development, beyond prototypes or research.
Having designed, built, and deployed autonomous agents in production.
Experience with multi-agent orchestration, state management, memory, and autonomous decision-making.
Practical knowledge of tool use, function calling and agent integration with APIs and external systems.
Experience implementing RAG pipelines and working with vector databases (Pinecone, Chroma, pgvector...).
Integration of LLM APIs such as OpenAI, Anthropic, or open source models.
Ability to design scalable and reliable architectures for AI systems in production.
Experience working with Docker and cloud deployments (AWS, GCP, or Azure).
Practical mindset: here we build real products, not academic research.
Ability to understand business problems and translate them into effective technical solutions.
Ease of adapting to change (yes, we are a startup 😄).
Constant curiosity and desire to improve both the product and the existing code.

✨ And you will shine even more if:

Nice to have

You have solid experience with Python for AI application development.
You master Symfony (PHP) for backend.
You have worked with Vue 3 and/or React on the frontend.
You have designed evaluation frameworks to measure the reliability and quality of agents.
You know techniques such as reflection, self-correction, and response verification in agents.
You feel comfortable working with distributed systems and modern architectures.

👨💻👩💻 What will you do at Sesame?

The role

Hello! 👋

At Sesame, we are building the next generation of our HR platform with multi-agent systems that automate real processes in production - no prototypes, no demos, no notebooks. We are looking for a Senior Fullstack Engineer with solid experience in Symfony (or Laravel with willingness to migrate), Python with FastAPI, and Vue 3 / React on the frontend, who has built and deployed autonomous agents in production and wants to lead the evolution of our applied AI platform.

If you have been doing fullstack for years and in the last 1-2 you have jumped into building agentic AI applications with LLMs - orchestration, RAG, tool use, memory, evals - this vacancy is for you.

What you'll do

Design and develop end-to-end agentic applications for the automation of HR processes.
Build multi-agent systems with orchestration, memory, and autonomous decision-making.
Implement RAG pipelines to provide business context to the agents.
Create guardrails and human-in-the-loop workflows to ensure reliability and compliance.
Maintain and evolve our backend in Symfony, Python, and NodeJS, and frontends in Vue 3 / React.
Define scalable architectures for AI systems in production.
Collaborate closely with product to transform business needs into real agentic solutions.

🚀 What will your growth in the company be?

Our stack

Backend: Symfony (PHP), Python (FastAPI), Node.js
Frontend: Vue 3, React
AI / ML: LangChain, LangGraph, Mastra, OpenAI, Anthropic
Infra: AWS, Docker, PostgreSQL, Redis
Data: pgvector, embeddings, RAG pipelines

🤓 What do we expect from you?

💻 At a technical level, it is indispensable that you have:

About Sesame HR

Sesame HR is a Spanish HR technology company that provides a cloud-based platform for managing human resources, including time tracking, payroll, and employee management. Founded in 2015, the company has grown to serve thousands of businesses across Spain and Latin America, positioning itself as a key player in the HR tech sector.

Industry: HR Tech
Founded: 2015
Employees: 100–500
Headquarters: Valencia, Spain
In Spain: Valencia
Website: sesamehr.com

Good to know if you are moving

Sesame HR is headquartered in Valencia, a vibrant Mediterranean city with a growing tech scene and lower cost of living compared to Madrid or Barcelona.
The company operates in Spanish and Portuguese markets, so fluency in Spanish is often essential for many roles, though tech positions may be more flexible.
As a fast-growing startup, employees may have the opportunity to work in a dynamic, scale-up environment with direct impact on product development.
Sesame HR offers remote work options, which can be attractive for international hires looking to live in Spain while working flexibly.

In their own words

About the company & team

In the first weeks, you will get to know the product, the team, and our approach to applied AI in depth, with technical onboarding and support.
In the first months, you will develop and evolve key agentic features, working hand in hand with the AI and product team.
As you gain context, you will begin to define architecture, propose improvements, and lead technical decisions.
Once you are fully established, you will have a key role in the evolution of our AI platform, directly influencing the roadmap and technical strategy.

✈️ Every functionality is a new adventure