Code.Hub  - Αγγελίεσ - Θέσεισ Εργασίασ

ai engineer – langchain & llm frameworks specialist

Dec 5, 2025 by 

Code.Hub

Αττική

Αττική

Hybrid

Πληροφορική

Permanent

Full Time

About the job

Our Client is seeking an experienced Senior AI Engineer with deep expertise in LangChain and modern LLM frameworks. You will lead the development of advanced LLM-driven applications, design complex RAG architectures, and guide the team in best practices for LLM engineering.

Key Responsibilities

LangChain & LLM Development

  • Design and develop advanced applications using LangChain, LangGraph, and LangSmith

  • Build complex chains, agents, and multi-agent systems

  • Implement custom tools, retrievers, and memory systems

  • Develop context-aware conversational AI and chatbot applications

  • Create workflow orchestration using LangGraph for complex reasoning tasks

  • Integrate multiple LLM providers (OpenAI, Anthropic, Cohere, Azure OpenAI)

  • Optimize prompt templates and output parsers

RAG & Vector Database Architecture

  • Design and implement advanced Retrieval-Augmented Generation (RAG) systems

  • Develop custom embedding strategies and chunking techniques

  • Work with vector databases such as Pinecone, Weaviate, Chroma, Qdrant, Milvus

  • Implement hybrid search (semantic + keyword) and reranking methods

  • Build document loaders and text splitters for diverse data sources

  • Optimize retrieval quality with metadata filtering and query expansion

  • Develop multi-modal RAG systems (text, images, documents)

Advanced LLM Techniques

  • Apply advanced prompt engineering: few-shotchain-of-thoughtReAct

  • Build function calling and tool-use patterns

  • Develop structured output with Pydantic models

  • Implement streaming responses and async pipelines

  • Build efficient caching strategies for cost optimization

  • Implement fallback mechanisms and robust error handling

  • Integrate guardrails and content moderation systems

Production & Monitoring

  • Deploy LangChain applications to production using LangServe

  • Integrate LangSmith for tracing, debugging, and evaluation

  • Implement monitoring and observability for LLM applications

  • Build evaluation frameworks for quality assurance

  • Optimize latency, cost, and token usage

  • Run A/B testing for prompt variations

  • Create dashboards to monitor key LLM metrics

Required Qualifications

Education

  • Bachelor’s degree in Computer Science, Machine Learning, or related field (required)

  • Master’s degree in AI/ML or Computer Science (preferred)

Experience

  • 5+ years of software development experience

  • 3+ years working with AI/ML and LLM applications

  • 2+ years hands-on experience with LangChain (mandatory)

  • Proven experience building production-grade LLM applications

  • Strong background with RAG architectures and vector databases

Technical Skills – LangChain Ecosystem

 LangChain Core (Required)

  • Expert-level knowledge of LangChain (v0.1+)

  • Deep understanding of Chains, Agents, Tools, Memory, Callbacks

  • Experience with LangChain Expression Language (LCEL)

  • Knowledge of LangGraph for complex workflows

  • Familiarity with LangSmith for monitoring/debugging

  • Experience deploying with LangServe

  • Understanding of LangChain Templates

LLM Providers & APIs

  • Strong experience with OpenAI API (GPT-4, GPT-3.5, embeddings)

  • Knowledge of Anthropic Claude API

  • Familiarity with Azure OpenAI Service

  • Experience with open-source models (Llama, Mistral, Mixtral)

  • Knowledge of Hugging Face Inference API

  • Understanding model capabilities, limitations, and pricing models

Vector Databases & Embeddings

  • Hands-on experience with Pinecone, Weaviate, or Chroma

  • Knowledge of embedding models (OpenAI, Cohere, sentence-transformers)

  • Understanding similarity search algorithms

  • Experience with metadata filtering and hybrid search

  • Knowledge of vector indexing strategies (HNSW, IVF)

Programming & Software Engineering

  • Expert-level Python (asyncio, type hints, Pydantic)

  • Experience with FastAPI

  • Strong understanding of async/await patterns

  • Strong software engineering fundamentals

  • Experience with Git, CI/CD, testing frameworks

 Cloud & Infrastructure

  • Experience with AWS (Lambda, ECS, S3, DynamoDB) or Azure

  • Docker containerization

  • Kubernetes (preferred)

  • Serverless architectures

  • API Gateway and load balancing

Core Capabilities

  • Deep understanding of LLM capabilities and limitations

  • Expertise in prompt engineering and optimization

  • Ability to design scalable LLM architectures

  • Strong understanding of cost optimization for LLM workloads

  • Knowledge of AI safety and responsible AI practices

  • Excellent problem-solving and communication skills

Preferred Qualifications

  • Contributions to LangChain or other open-source LLM projects

  • Experience with LlamaIndex, Haystack, or similar frameworks

  • Knowledge of fine-tuning (LoRA, QLoRA)

  • Experience with multi-agent systems and AutoGPT patterns

  • Knowledge of semantic caching and query optimization

  • Experience with document intelligence and OCR

  • Understanding transformer architectures

  • Experience with evaluation frameworks (RAGAS, TruLens)

  • Experience with streaming and real-time LLM processing

  • Blog posts, tutorials, or presentations on LangChain

  • Cloud certifications

What They Offer

  • Highly competitive salary and equity package

  • Full health, dental, and vision insurance

  • Generous budget for professional development and certifications

  • Flexible working arrangements (remote/hybrid options)

  • Access to cutting-edge AI infrastructure and LLM APIs

  • Collaborative environment with world-class AI professionals

  • Participation in conferences and AI community events

  • Opportunities for technical leadership and mentorship

  • Influence over the company’s AI strategy

 Success Metrics

Success in this role will be measured by:

  • Quality and performance of LangChain applications

  • Reduction in latency and improved cost efficiency

  • Accuracy and relevance of RAG systems

  • Adoption of best practices across the team

  • Speed of delivery for new AI features

  • User satisfaction with AI-powered features

  • Technical leadership and mentorship impact

  • Contribution to documentation and knowledge base

Technologies You Will Work With

LLM Frameworks

  • LangChain, LangGraph, LangSmith, LangServe

  • OpenAI API, Anthropic Claude API

  • Hugging Face Transformers

Vector Databases

  • Pinecone, Weaviate, Chroma, Qdrant

  • PostgreSQL with pgvector

Development Stack

  • Python 3.11+, FastAPI, Pydantic

  • Docker, Kubernetes

  • AWS/Azure cloud services

  • Git, GitHub Actions

Monitoring & Observability

  • LangSmith

  • Prometheus, Grafana

  • DataDog, New Relic

Hybrid

Πληροφορική

Permanent

Full Time

About the company

Code.Hub is a Recruitment Agency, a Learning & Development partner, an Extended Team and Project Delivery expert in the Tech Industry.

We source and train the best candidates in Tech Industry.

With a team of 150+

  • Tech-specific Recruiters
  • Certified Trainers
  • Software Development specialists

we are prepared for every challenge.

Using exclusively Agile methodologies, we help companies of all levels and technologies to extend their vision many step forward.



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