S

Lead AI Engineer

STI
2 hours ago
Full-time
On-site
Job Title

:

Lead AI Engineer Location:

Austin, Texas (Hybrid)

Duration: Longterm Contract

Lead AI Engineer (Search Modernization)

Mandatory Skills: Elastic Search, OpenSearch, Python, LLM, GenAI, Semantic Search, Re-Ranking, AWS, Search Engineer

Job Description:

We are looking for an

AI Engineer

to modernize and enhance our existing

regex/keyword-based Elastic Search system

by integrating

state-of-the-art semantic search, dense retrieval, and LLM-powered ranking

techniques. This role will drive the transformation of traditional search into an

intelligent, context-aware, personalized, and high-precision search experience .

The ideal candidate has hands-on experience with

Elastic Search internals ,

information retrieval (IR) ,

embedding-based search ,

BM25 ,

re-ranking ,

LLM-based retrieval pipelines , and

AWS cloud deployment .

Roles & Responsibilities

Modernizing the Search Platform Analyze limitations in current

regex & keyword-only

search implementation on ElasticSearch. Enhance search relevance using:

BM25 tuning Synonyms, analyzers, custom tokenizers Boosting strategies and scoring optimization

Introduce

semantic / vector-based search

using dense embeddings. 2. LLM-Driven Search & RAG Integration

Implement

LLM-powered search

workflows including:

Query rewriting and expansion Embedding generation (OpenAI, Cohere, Sentence Transformers, etc.) Hybrid retrieval (BM25 + vector search) Re-ranking using cross-encoders or LLM evaluators

Build

RAG (Retrieval Augmented Generation)

flows using ElasticSearch vectors, OpenSearch, or AWS-native tools. 3. Search Infrastructure Engineering

Build and optimize search APIs for latency, relevance, and throughput. Design scalable pipelines for:

Indexing structured and unstructured text Maintaining embedding stores Real-time incremental updates

Implement caching, failover, and search monitoring dashboards. 4. AWS Cloud Delivery

Deploy and operate solutions on

AWS , leveraging:

OpenSearch Service or EC2-managed ElasticSearch Lambda, ECS/EKS, API Gateway, SQS/SNS SageMaker for embedding generation or re-ranking models

Implement CI/CD for search models and pipelines. 5. Evaluation & Continuous Improvement

Develop search evaluation metrics (nDCG, MRR, precision@k, recall). Conduct A/B experiments to measure improvements. Tune ranking functions and hybrid search scoring. Partner with product teams to refine search behaviors with real usage patterns. Required Skills & Qualifications

5-10 years of experience in

AI/ML, NLP, or IR systems , with hands-on search engineering. Strong expertise in

ElasticSearch/OpenSearch : analyzers, mappings, scoring, BM25, aggregations, vectors. Experience with

semantic search :

Embeddings (BERT, SBERT, Llama, GPT-based, Cohere) Vector databases or ES vector fields Approximate nearest neighbor (ANN) techniques

Working knowledge of

LLM-based retrieval

and

RAG architectures . Proficient in

Python ; familiarity with Java/Scala is a plus. Hands-on AWS experience (OpenSearch, SageMaker, Lambda, ECS/EKS, EC2, S3, IAM). Experience building and deploying APIs using

FastAPI/Flask

and containerizing with

Docker . Familiar with typical IR metrics and search evaluation frameworks. Preferred Skills

Knowledge of

cross-encoder and bi-encoder

architectures for re-ranking. Experience with

query understanding , spell correction, autocorrect, and autocomplete features. Exposure to

LLMOps / MLOps

in search use cases. Understanding of

multi-modal search

(text + images) is a plus. Experience with

knowledge graphs

or metadata-aware search.