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Digital Twin

A chatbot that answers questions about the career on this page, in the visitor’s language. Demonstrates an agentic RAG system: several agents filter each question, retrieve the documents, write a professional answer, and send push notifications, while semantic vector search and BM25 lexical search run concurrently and are reranked with Cohere for precision.

How I built it

Designed an orchestrated multi-agent workflow with LangGraph and OpenAI agents, breaking the conversation into specialised steps. Each agent can access the tools it needs, while structured outputs and guardrails provide consistency and control over the responses.

To improve retrieval quality, implemented a hybrid RAG approach combining BM25 lexical search and semantic vector search. Relevant documents are retrieved from the Chroma database and then reranked with Cohere before being provided as context to the agents.

Built the backend with FastAPI, exposing the agentic RAG pipeline through APIs that connect the AI layer with the frontend.

01 — Problem

Static pages make visitors dig for answers

Traditional career websites require visitors to navigate static pages to understand a candidate’s experience, creating an opportunity for a more interactive way to explore professional information.

02 — Product

Ask about my career in plain language

An AI-powered Digital Twin that allows recruiters and visitors to ask natural-language questions about my experience, projects, skills and professional background.

03 — Key decisions

AI as the interface, grounded in facts

AI as an interface · Grounded professional knowledge · Structured career context · Controlled conversational scope

04 — Outcome

An interactive AI profile

Interactive AI profile · Conversational career exploration · Structured professional knowledge base · AI agent foundation

05 — My contribution

From AI design to end-to-end development

Product strategy · AI & data design · Conversational UX · Knowledge architecture · End-to-end development

Built with

  • LangGraph
  • OpenAI Agents SDK
  • Chroma
  • Cohere
  • FastAPI
  • Next.js
The Digital Twin’s own page, showing a chat with Andreu Ortega’s AI assistant: it introduces itself, then answers a question about its AI expertise with a list that covers generative AI, agentic AI and AI projects
The Digital Twin’s own page, showing a chat with Andreu Ortega’s AI assistant: it introduces itself, then answers a question about its AI expertise with a list that covers generative AI, agentic AI and AI projects

The chatbot on its own page

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The chatbot on its own page
The Digital Twin in Telegram, as the bot Andreu’s Career Bot: it introduces itself as the AI career assistant for Andreu Ortega and suggests four questions, then begins to answer which kinds of roles fit his experience
The Digital Twin in Telegram, as the bot Andreu’s Career Bot: it introduces itself as the AI career assistant for Andreu Ortega and suggests four questions, then begins to answer which kinds of roles fit his experience

The chatbot in Telegram

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The chatbot in Telegram