> Markdown version of [/jobs/ext/2726588-backend-engineer-data-platform-ai-agents](https://www.wearedevelopers.com/jobs/ext/2726588-backend-engineer-data-platform-ai-agents). Every page supports `.md` or `Accept: text/markdown`. Links point to the HTML versions so they work for humans too. Agent guide: [/agents.md](https://www.wearedevelopers.com/agents.md). --- # Backend Engineer - Data Platform & AI Agents - **Company:** Jus Mundi - **Location:** Inconnu, France - **Experience:** Expert - **Contract:** Permanent contract - **Skills:** HTML, Application Programming Interfaces (APIs), Artificial Intelligence, Continuous Integration, Data as a Services, Data Infrastructure, DevOps, Elasticsearch, Fault Tolerance, Python (Programming Language), PostgreSQL, TypeScript, Web Crawlers, Data Processing, ReactJS, Large Language Models, Indexer, Backend, Kubernetes, Free and Open-Source Software, Api Design, Full-text Search - **Published:** September 5, 2026 - **Apply:** https://startup.jobs/senior-backend-engineer-data-platform-ai-agents-jus-mundi-sas-8950750 ## About the Role This is a hands-on senior role with high ownership and real architectural latitude. Backend depth is the core of the role; you should be comfortable working with LLMs and agent orchestration as a first-class part of the system, but this is not a modelling or research position., * Backend Engineering Depth (critical requirement): 5+ years shipping and operating production backend or data services, with strong Python . Async I/O, API design, testing discipline, and a track record of owning services in production rather than handing them over. * Agentic & LLM Systems (critical requirement): Hands-on experience building agent orchestration in production - tool/function calling, memory and state management, error recovery, bounded context, and deterministic contracts wrapped around a non-deterministic core. Custom architecture or a framework (LangGraph, LangChain, LlamaIndex, or similar) are equally welcome; what matters is that you can point at something you shipped and had to keep working. * Data Modelling: Postgres in depth - schema design for heterogeneous and evolving data, jsonb versus typed columns, indexing, full-text search, migrations under load, and a real feel for transactional correctness. * Systems Judgment: Queues or streams, idempotency, at-least-once semantics, atomic writes, object storage treated as immutable truth. You design for retry, reproducibility and graceful degradation rather than assuming the happy path. * Document & Data Processing: PDF and HTML text extraction, OCR, and structured metadata extraction with LLMs - plus realistic judgement about where quality breaks and what that costs downstream. Multilingual corpora a strong plus. * Ownership & DevOps Mentality: Containers, CI/CD, Kubernetes or equivalent. You build it, you run it, you own it - including when it pages. * Senior Behaviours: Turns ambiguity into a plan and a document others can act on; makes explicit trade-offs rather than reaching for the perfect solution; mentors peers; takes accountability for outcomes. Fluent English (our working language, oral and written)., * Web crawling and scraping at scale - pagination traps, rendering, rate limits, source drift, dedup. We are taking an agentic-first approach, so this is a real bonus rather than a requirement. * Legal tech, or another domain where being confidently wrong is expensive. * Search infrastructure (Elasticsearch / OpenSearch) and multilingual retrieval. * Enough TypeScript/React to contribute to our internal back-office UI. * Experience with the MCP ecosystem, or agent tooling you built yourself. * Open-source contributions, or a portfolio of systems you can talk through in depth ## Description Jus Mundi is building the AI layer for international law and arbitration - turning a vast, multilingual corpus of case law, treaties, and legal analysis into answers practitioners can trust. We are now expanding beyond arbitration into new legal verticals, and each one potentially adds millions of documents to that corpus. To support that, we are building a new Data Platform: an autonomous, agent-driven system that discovers, acquires, processes and enriches legal documents end to end, and becomes the company-wide source of truth that Search, AI and Product all consume. It replaces our legacy ingestion paths rather than patching them. We are looking for a Senior Backend Engineer with hands-on AI experience to build it with us. You will own the services behind the platform: the agents that acquire documents from hundreds of heterogeneous sources, the transactional catalog and API that everything reads from, and the processing layer that turns raw files into searchable, well-described documents., We're proud of our multicultural team representing 37 nationalities! To ensure smooth communication, please apply in English (CV and application form questions). ## Related Videos - [The Resilience of the World Wide Web](https://www.wearedevelopers.com/videos/1281-the-resilience-of-the-world-wide-web) - [From DevOps to Scaled DevOps: How We’re Rebuilding Continuous Delivery as a Platform](https://www.wearedevelopers.com/videos/100018-from-devops-to-scaled-devops-how-we-re-rebuilding-continuous-delivery-as-a-platform) - [Developing the Backend with Stefan Lingler, CTO at Shpock](https://www.wearedevelopers.com/videos/100360-developing-the-backend-with-stefan-lingler-cto-at-shpock) - [Shipping Faster with Less: Render on Cloud Hosting, AI Workloads, and the Future of DevOps](https://www.wearedevelopers.com/videos/1894-shipping-faster-with-less-render-on-cloud-hosting-ai-workloads-and-the-future-of-devops) - [NoLoJS - Avoiding JavaScript Cruft with HTML and CSS - Aaron T. Grogg](https://www.wearedevelopers.com/videos/1806-nolojs-avoiding-javascript-cruft-with-html-and-css-aaron-t-grogg) - [When Should You Use an Agent? Architectural Trade-offs in Agentic Systems](https://www.wearedevelopers.com/videos/100109-when-should-you-use-an-agent-architectural-trade-offs-in-agentic-systems) ## Related Articles - [Graph and AI Trends 2026: Why Is AI Running but Not Yet Delivering?](https://www.wearedevelopers.com/magazine/680-graph-and-ai-trends-2026-why-is-ai-running-but-not-yet-delivering) - [Dev Digest 121 - AI goes offline](https://www.wearedevelopers.com/magazine/456-dev-digest-121-ai-goes-offline) - [Dev Digest 120 - Apple and peers](https://www.wearedevelopers.com/magazine/455-dev-digest-120-apple-and-peers) - [How We Built a Worry-Free System That Runs for 10+ Years – And What We’d Do Again](https://www.wearedevelopers.com/magazine/751-how-we-built-a-worry-free-system-that-runs-for-10-years-and-what-we-d-do-again) - [Dev Digest 210: AI Agents Are Go! Is MCP Dead? LLMs Crack Anonymity](https://www.wearedevelopers.com/magazine/709-dev-digest-210-ai-agents-are-go-is-mcp-dead-llms-crack-anonymity) - [What Are Large Language Models?](https://www.wearedevelopers.com/magazine/304-what-are-large-language-models)