Open to contracts & startup collaborations.

Building AI Systems
from infrastructure
to interface.

RAG Pipelines/Python/Cloud Infrastructure/Next.js

I design and build AI-enabled applications end to end - from retrieval architecture and LLM integration to cloud infrastructure and frontend delivery. Currently building a production RAG system for a healthcare AI platform with hybrid search, multi-layer safety guardrails, observability, and real-time streaming.

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Expertise

Technical Expertise

Working daily across Python, Next.js, GCP, and Terraform - delivering complete systems from infrastructure to interface.

🧠

AI Engineering

Building production RAG pipelines with hybrid retrieval, multi-layer guardrails, observability, and LLM integration.

RAG PipelinesLLM IntegrationvLLMOllamaChromaDBLangfuseGuardrails
⚙️

Backend

Python-first backend development with FastAPI, async pipelines, caching strategies, and PostgreSQL.

PythonFastAPIPostgreSQLRedisNode.jsREST APIsWebSocket
🎨

Frontend

Component-driven UI with Next.js, React, and TypeScript. Design systems, state management, and performance.

Next.jsReactTypeScriptTailwind CSSZustandStorybookCypress
☁️

Cloud & Infrastructure

Infrastructure as code with Terraform on GCP. Docker, CI/CD, and environment reproducibility.

TerraformGCPDockerFirebaseCloud FunctionsCI/CD

Portfolio

Featured Projects

Selected work spanning healthcare AI, global e-commerce, and recruitment platforms.

ARGC
ARGC RAG Pipeline
Production RAG system for a patient-facing IVF clinic AI assistant. Multi-stage pipeline with hybrid retrieval, multi-layer safety guardrails, and full observability.
PythonFastAPIChromaDBvLLMOllamaLangfuseRedisPostgreSQLDocker

Key Contributions

  • Designed hybrid retrieval - BM25 + vector search with Reciprocal Rank Fusion, intent and treatment-stage boosting
  • Built multi-layer guardrails: input safety, output validation, dialog monitoring, medical safety, faithfulness checking
  • Introduced ChromaDB and built the ingestion pipeline from Notion CSV exports
  • Designed two-tier response caching (L1 in-memory + L2 Redis) - reduced repeat query latency from ~5s to under 10ms
  • Integrated Langfuse for full request tracing with per-stage spans and confidence scoring
  • Implemented circuit breaker pattern on guardrails for resilience
  • Built comprehensive test suite across unit, integration, and API layers
Outcome

Production system serving real patients at an IVF clinic. Evaluation test cases across multiple datasets for regression testing.

ARGC
ASHA - AI Fertility Assistant
Next.js application with real-time WebRTC video avatar streaming, voice interaction via Deepgram, WebSocket AI responses, and Terraform-managed GCP infrastructure.
Next.js 14TypeScriptReactZustandWebRTCWebSocketFirebasePythonTerraformGCPJestCypress

Key Contributions

  • Built the entire frontend - custom React hooks organised by domain (auth, avatar, chat, voice, WebSocket, session), component library, and Zustand state management
  • Implemented dual interaction modes: text chat with streaming responses, and video mode with real-time voice capture, transcription, and avatar lip-sync
  • Built admin dashboard - conversation viewer, search/filter, PDF transcript export, analytics
  • Wrote Python Cloud Functions for analytics logging and embryology access control
  • Designed Terraform infrastructure: VPC, Cloud SQL, Cloud Functions, Secret Manager, IAM - across dev/staging/prod
  • Built unit and end-to-end test coverage with Jest and Cypress
Outcome

Live production app serving IVF patients. Dual interaction modes (chat + video avatar). Full admin visibility into conversations. Infrastructure reproducible across three environments via Terraform.

PVH
PVH Unified Checkout
Unified checkout experience for Calvin Klein and Tommy Hilfiger across 25 countries, replacing fragmented per-country implementations.
Next.jsReactTypeScriptRedux ToolkitStorybookNode.jsAdyenCypress

Key Contributions

  • Consolidated fragmented per-country checkout codebases into a single unified platform serving both brands across 25 countries
  • Engineered the component design system using Storybook for UI consistency across both brands and all country configurations
  • Integrated Adyen payment gateway - credit/debit, PayPal, 3DS1/3DS2 authentication flows
  • Implemented multi-lingual support, dynamic address fields per country, promotions management, and session handling
  • Optimised frontend performance across server-side rendered pages and checkout flows
  • Built reusable React component library shared across multiple development teams
  • Built comprehensive test coverage - unit (Jest), integration (React Testing Library), E2E (Cypress)
Outcome

Unified checkout live across 25 countries for two major fashion brands. Single maintainable codebase replacing fragmented per-country implementations.

Career

Professional Journey

18 years across healthcare AI, global e-commerce, fintech, and biotech.

Full-Stack Engineer
Sep 2024 - Present
ARGC / Blue Door Fertility
London, UK · Contract
PythonFastAPIChromaDBLangfuseNext.jsWebRTCTerraformGCP
Building two connected production systems for a healthcare AI platform: a Python RAG pipeline and a Next.js conversational avatar interface, with supporting GCP infrastructure.
Senior Frontend Developer
Apr 2023 - Sep 2024
Experts Circle
London, UK · Contract
ReactTypeScriptAWS LambdaDynamoDBStorybookTerraform
Delivered key features for a recruitment platform including job aggregation, candidate matching, and notification systems. Built reusable component library and mentored junior developers.
Senior Frontend Developer
Sep 2019 - Mar 2023
Wunderman Thompson Commerce (VML)
Watford, UK · Contract
ReactRedux ToolkitNext.jsTypeScriptAdyenStorybook
Unified checkout for Calvin Klein and Tommy Hilfiger across 25 countries. Integrated Adyen payments, multi-lingual support, and SSR-optimised performance.
Software Engineer
Mar 2019 - Sep 2019
Sartorius
Royston, UK · Contract
ReactRedux ToolkitGraphQLPythonMongoDBAzure
Built the frontend for a clone selection application used in biotech research. Integrated GraphQL APIs with React and Redux Toolkit, and worked with Python services on Azure infrastructure.
UI Developer
Sep 2018 - Dec 2018
Barclays
Northampton, UK · Contract
ReactRedux ToolkitJavaScript
Developed single-page applications for Barclaycard financial services using React and Redux. Focused on responsive design and accessibility compliance for banking products.
Senior Frontend Developer
May 2015 - Jul 2018
Flixmedia Limited
London, UK · Permanent
ReactVue.jsAngularRedux ToolkitTypeScript
Built e-commerce web solutions for major retail brands. Introduced Vue.js for an internal dashboard application, led frontend architecture decisions, and mentored junior developers across multiple frameworks.
Frontend Developer
Dec 2010 - May 2015
BNP Paribas (Cardif Pinnacle Insurance)
London, UK · Permanent
HTML5CSS3JavaScriptjQuery
Built UI/UX for online insurance and financial products. Ensured W3C compliance and accessibility standards, implemented responsive designs, and integrated with backend APIs for policy management systems.

Recommendations

What colleagues say

From product leaders, engineers, and managers I've worked with across healthcare AI and enterprise e-commerce.

“I worked with Saroz on an AI customer support avatar product at Blue Door Fertility. He is an intelligent and capable engineer with a great can-do attitude. A real pleasure to work with - I hope I can again in future.”

Gideon Summerfield

Gideon Summerfield

Product Leader, Sky, BBC, Hive, Start-ups

“Saroz always goes above and beyond to find the best technical solutions to issues and new feature requests. Thanks to his exceptional attention to detail, he produces top quality code. He is great at collaborating with other team members in all phases of the project, he is flexible and always willing to help his colleagues.”

Marianna Falchi

Marianna Falchi

Business Analyst, VML

“Saroz is very professional and talented developer. He is curious and extremely knowledgeable. He has great technical skills, and always seeks to further them. Saroz is ready to help the team members to achieve their goals. Hard working, dedicated, adaptable and very focused.”

Katarzyna Hrycek-Robinson

Katarzyna Hrycek-Robinson

Senior Test Engineer, VML

“It was a true nice experience to work with Saroz. His sharp eye and craftsmanship has helped a lot to achieve the product goals. He works thoroughly and has a high quality standard for coding. He's a real team player and a nice guy.”

Michiel Kramer

Michiel Kramer

Senior Lead Product Owner, PVH / Calvin Klein / Tommy Hilfiger

“Saroz was a core team member in a development team that built and rebuilt ecomm checkout of two major fashion brands, TH and CK. He has demonstrated a very high standard and quality of work throughout the project.”

Justyna Latko

Justyna Latko

Senior Product Manager, PVH Europe B.V.

“Saroz is a solid front-end developer that worked in a product team on one of our major accounts. He is very experienced in React technologies, communicates well and conducts himself in a professional manner. I would happily use his services again and recommend him.”

Nat Gale

Nat Gale

Head of Product Engineering EMEA, Magentus

“Saroz and I have worked together in a scrum team to improve the Tommy Hilfiger & Calvin Klein checkouts. It has been a pleasure working with Saroz from start to end. He is a dedicated, hard working developer who delivers high quality code. It is easy to communicate with Saroz, always willing to help out. Thanks Saroz!”

Janna van Aalderen

Janna van Aalderen

Interim Product Owner / Project Manager, Your Guiding Light

Connect

Let's work together

Open to contracts & startup collaborations.

Open to contract roles in the UK where I can work across the stack on AI-enabled applications - retrieval systems, LLM integration, cloud infrastructure, and the frontend that makes it all accessible.

LinkedIn
in/sarozmitra
Location
United Kingdom