I build production-ready data systems and backend infrastructure for companies that need their data reliable, highly queryable, and 100% automated. If your team is still manually exporting CSVs from SaaS tools every week, dealing with fragile pipelines, or struggling to scale database architecture, I design the systems that eliminate those bottlenecks. Here is how I help clients scale: █ 1. DATA ENGINEERING & WAREHOUSING I specialize in moving massive data volumes between disparate sources, databases, and warehouses while ensuring absolute data integrity, scheduling, and monitoring. • Enterprise Cloud Migration: Migrated 367M+ rows across 5 national well & gas datasets from on-prem SQL Server to Snowflake via Azure Data Factory (including year-based partitioning for 275M+ row tables) with zero data loss. • Custom Pipeline Development: Developed a Python pipeline converting ESRI Geodatabase files to GeoParquet, loading 96 spatial layers into Snowflake using native GEOGRAPHY columns. • Database Architecture: Built a regulatory database covering 354 interstate pipeline operators and 275K fact rows (2011–2025). • Multi-Source Warehousing: Engineered an Azure-provisioned (Terraform/Docker) PostgreSQL warehouse consolidating NetSuite (SuiteQL) and SharePoint (Graph API) data to feed daily operational PowerBI dashboards. • Financial Syncs: Automated a 68-entity QuickBooks Online + Turvo TMS synchronization into PostgreSQL with secure OAuth2 authentication and scheduled refreshes. • Automated Ingestion: Set up a T-1 Crude Oil database managing 6+ OCR Excel layouts with robust deduplication logic and automated GIS enrichment. █ 2. BACKEND SYSTEMS & CUSTOM INTEGRATIONS I engineer API-heavy backends and third-party integrations where data reliability and complex business logic cannot afford to fail. • AI-Driven Automation: Built an AI applicant review system processing ~300 forms/day using 26 deterministic rules combined with LLM edge-case handling, featuring custom forms, SSO, and a two-way HubSpot sync. • E-Commerce Infrastructure: Developed a high-performance custom product builder utilizing Next.js 15 App Router, Express, Prisma, and PostgreSQL, optimized with GA4 e-commerce tracking and JSON-LD for SEO. • Marketplace Integrations: Built an Amazon Selling Partner API integration for order/inventory sync, settlement reconciliation, and 7 custom Streamlit analytics reports. ──────────────────────────────────────── TECHNICAL PROFICIENCIES • Cloud & Infra: Azure (Data Factory, Functions, Blob, SQL), AWS (Lambda, RDS), Terraform, Docker, PM2 • Databases & Warehouses: Snowflake, PostgreSQL, SQL Server, MySQL, MariaDB • Data/ETL Stack: Python, pandas, geopandas, pyarrow, openpyxl, GeoParquet, Databricks • Backend & Languages: Node.js, TypeScript, FastAPI, Flask, Bun, Prisma, SQLAlchemy, T-SQL, PL/pgSQL • Core Integrations: NetSuite, QuickBooks, Amazon SP-API, Microsoft Graph, HubSpot, Turvo, ESRI GDB • AI Orchestration: OpenAI API, Pydantic, Instructor ──────────────────────────────────────── HOW WE WILL WORK TOGETHER I operate as a consultative partner, not just a task-taker. I ask deep structural questions before writing a single line of code to catch architectural flaws early. You will receive proactive progress updates before you ever have to ask for them. Every system I deliver features comprehensive error handling, logging, and monitoring built-in from day one. If you have a complex data pipeline, a broken integration, or a backend system that needs to scale, send me a brief message outlining your current setup. I will give you a clear, objective analysis of the best path forward. barumkhan.dev

I build production-ready web apps and mobile solutions that clients can actually ship — not prototypes. With hands-on experience in C#, ASP.NET Core, Flutter, and SQL Server, I deliver clean architecture and enterprise-grade code that scales. My current focus: integrating AI into real-world applications. I help businesses add LLM-powered features (OpenAI, Claude API, LangChain) into existing .NET systems — from intelligent document processing and chatbots to automated workflows. If you need AI that fits into your stack, not just a demo, I'm the right person. What I work with: → Backend: C#, ASP.NET Core MVC, VB.NET, REST & Web APIs → Frontend/UI: DevExpress, UI3, Razor Views → Mobile: Flutter (cross-platform iOS/Android), Kotlin (native Android) → Databases: SQL Server, MySQL — query optimization, schema design, EF Core → AI/ML: OpenAI API, Anthropic Claude API, prompt engineering, RAG pipelines I've worked with clients across business software, ERP Solutions, inventory systems, field service apps, and internal tooling. I understand deadlines, legacy code, and the difference between a clean proof-of-concept and software ready to hand off to a client. If your project needs a developer who won't need hand-holding on architecture, DM me with your brief.

One thing I've learned in my career is that Power BI projects succeed when they start with understanding first - not dashboards. Before I build anything, I take time to understand the business, the people, and the decisions Power BI needs to support. That's how I create solutions that don't just look good - but drive real outcomes. Specialties: - Financial reporting: P&L statements, balance sheet, income statement, cash flow analysis, budgeting, forecasting, variance analysis - Operational analytics: Sales performance, KPI dashboards, YoY/QoQ/MoM comparisons, customer segmentation, retention, trend analysis - Technical expertise: Advanced DAX measures, Power Query transformations, Power Pivot, star schema design, time intelligence functions Why clients choose me: ✦ Business-first approach - 10+ years in finance, banking, and sales means I understand the decisions behind the data ✦ Technical + design excellence - Dashboards that perform well and look professional for any audience ✦ Independent execution - I work from a brief, ask the right questions, and deliver results with clear communication Need Power BI solutions that combine technical excellence with business understanding? Send me an invite or message. Nenad

Experienced Analytics Leader with a demonstrated history of working in various startups and corporate including Grab and Nestle' . Skilled in building and training Data Analytics team, Business Intelligence, Python (Programming Language), Strategy, MS Suite. Strong research professional with a Master of Science (MS) focused in International Business from Hult International Business School.

Data Engineer | Data Analyst | Big Data Consultant I specialize in building scalable data solutions that streamline workflows, automate processes, and unlock valuable business insights. With over 4 years of experience, I have helped businesses integrate, transform, and visualize their data for data-driven decision-making. 🔹 What I Do: ✔ ETL & Data Pipelines – Automating data ingestion using Python, Fivetran, Airbyte, and Keboola ✔ Data Transformation – Structuring and optimizing data with DBT, SQL, and Dataform ✔ Data Warehousing – Managing large-scale databases in BigQuery, Snowflake, SQL Server, Postgres, and AWS Redshift ✔ Data Visualization – Creating insightful dashboards in Looker Studio, Power BI, Metabase, and Tableau 🔹 Data Sources I Have Worked With: ✔ Marketing Data – Google Ads, Meta Ads, LinkedIn Ads, TikTok Ads, Snapchat Ads, Reddit Ads ✔ CRM & Sales – HubSpot, Salesforce, Go High Level, SPP ✔ E-commerce – Shopify, WooCommerce, Amazon Seller Central ✔ Analytics & Tracking – Google Analytics, Mixpanel, Adjust ✔ Payments & Invoicing – Stripe, Xero ✔ Forms & Email Marketing – Typeform, Klaviyo, Active Campaign 🔹 Why Work With Me? ✔ I build automated, scalable, and efficient data solutions that save time and optimize business operations. ✔ My expertise in both data engineering and data analytics allows me to bridge the gap between raw data and actionable insights. ✔ I focus on clean, structured, and well-documented data solutions that are easy to maintain and expand. I’m here to help you automate, clean, and visualize your data so you can focus on growing your business. Let’s discuss how I can contribute to your success!

I build AI automation systems that eliminate manual work across your CRM, e-commerce stack, and fulfilment tools — connecting n8n, LLMs, and MCP so your workflows run without anyone babysitting them. With 5+ years of software engineering experience — including enterprise-grade Java & Spring Boot backend development — I've shipped production automation for multi-brand eCommerce businesses and SaaS platforms: syncing 12 WooCommerce stores across 4 regions into HubSpot in real time, building AI pipelines that audit hundreds of supplement labels automatically, and integrating voice AI systems for sales teams. That backend depth means the pipelines I build aren't just no-code chains — they're engineered with the same rigor as production software: proper error handling, retry logic, and monitoring from day one. 54 completed projects on Upwork, Top Rated, with consistent 5-star feedback. What I build: n8n workflow automation and agentic pipeline development AI agents with real-time tool access via Model Context Protocol (MCP) RAG pipelines using PostgreSQL, Supabase, and MongoDB LLM integrations (OpenAI, Claude, Gemini) with structured outputs and retry logic CRM and ERP integrations: HubSpot, Salesforce, NetSuite, QuickBooks eCommerce sync: WooCommerce, Shopify with full error handling Webhook and REST API integrations across any stack Backend engineering support for automation projects: Java, Spring Boot, microservices, REST APIs, database design How I work: I audit your existing setup first, then design and deploy end-to-end. Every pipeline I build has error handling, retry logic, and monitoring built in so it keeps running after I hand it over. Industries I've worked in: Health & wellness (EU/UK compliance), multi-brand eCommerce, B2B SaaS, and voice AI for sales. Tools: n8n · OpenAI · Claude · Gemini · HubSpot · WooCommerce · Shopify · Supabase · PostgreSQL · MongoDB · Salesforce · ActiveCampaign · NetSuite · QuickBooks · Java · Spring Boot · TypeScript · Python · Node.js

AI/ML engineer who cut a 6-hour manual review process to under 10 minutes using document AI and computer vision. 100% job success across 26 projects, $100K+ earned. I build AI systems that do real work. Results from deployed systems: Manufacturing Doc-AI — Computer vision (YOLOv8) + NLP on architectural blueprints for the largest US casework manufacturer. Estimation from 2-6 hours to under 10 min. 91% recall, 84% precision on production drawings. Detects cabinetry, reads MasterFormat specs, outputs structured estimates. AI Document Agent — Natural language search over 500MB+ PDF spec files. Answers with page + paragraph citations in under 30 seconds. Previously 30+ minutes per manual search. Multi-Agent Investment Research — LLM-based multi-agent system processing live financial data. Autonomous agent coordination with retrieval, analysis, and reporting pipelines. Backend & Long-Term Engagements — 4+ years with Xperi (DTS/TiVo), code running in BMW and Tesla. 5+ years with Internet Archive maintaining a 40,000-line Python platform powering worldwide book scanning. What I ship: LLM agents with tool calling, RAG over proprietary data, document AI (OCR + layout extraction), computer vision, and production Python backends. Weekly milestones with acceptance criteria. Handover includes runbooks, dashboards, and training.

Hands on with server side solution using Spring, Hibernate, J2EE 7 and LAMP (PHP) stack for the last 15 years. - Proficient with building distributed fault-tolerant, soft-real time, microservices based system using vert.x and dropwizard. - Proficient with RDBMS like MySQL, PostgreSQL; NoSQL like Redis, Riak and JCR repositories like ModeShape. - Proficient with UI and mobile hybrid apps like ExtJS 4/5, GWT 2.7, JQuery UI, JQuery Mobile, ExtJs Touch, Angular, Ionic and Cordova - Hands on with "process" based and "case" based implementation using BPMN 2.0 and CMMN 1.0 using Camunda process engine. - IOT sensor based solutions using Arduino/Raspberry PI/BeagleBone and analytics using Esper Complex Event Processing engine for realtime analytics less > Proficient in Spring 2.x framework and AOP using AspectJ AOP framework. > Proficient in building agent based systems using OSGI specs (Equinox and Knopflerfish containers) > Dealt in indigenous and component-based J2EE based solutions for clients. > Proficient in using OSS tools like Ant, Log4j, Tomcat, Hibernate, MySQL etc. > Hands on different Operating systems including Linux, Solaris and Win2k. > SCRUM and UML certified

I’m a Senior Java Backend Engineer with over 14 years of experience building mission-critical systems in fintech, with a strong focus on payments, lending platforms, and core banking solutions. I specialize in Java and Spring Boot, and design backend systems that are secure, scalable, and capable of handling high-volume financial transactions with consistency and reliability. I’ve worked on systems involving payment processing, transaction workflows, loan management, and integrations with external financial services and APIs. This includes designing and building robust microservices architectures that support real-time and asynchronous processing, ensuring data accuracy, fault tolerance, and seamless service communication. I understand the importance of idempotency, transaction integrity, and failure handling in financial systems where even minor inconsistencies can have significant impact. Security and compliance are central to my approach. I have strong experience implementing secure authentication and authorization using Spring Security, token-based systems, and role-based access control. I build APIs and backend services that align with financial industry expectations around data protection, auditability, and reliability. From a technical standpoint, I bring deep expertise in Spring Boot, microservices, REST API design, JPA/Hibernate, and relational databases like MySQL and PostgreSQL. I’m comfortable designing systems from scratch as well as improving and scaling existing platforms, optimizing performance, and ensuring stability under load. I also have hands-on experience with AWS and Google Cloud, and have worked on deploying and managing backend systems in cloud environments. I understand how to design cloud-ready architectures, implement CI/CD pipelines, and ensure systems are resilient, observable, and production-ready. What sets me apart is my ability to think beyond just implementation. In fintech systems, correctness, reliability, and long-term maintainability matter more than quick fixes. I focus on building clean, well-structured systems that not only meet current requirements but are also prepared for future scale, regulatory needs, and product evolution. If you’re building or scaling a payments platform, lending system, or core banking backend and need someone who understands both the technical and domain challenges, I’d be glad to contribute.

I’m a full stack developer, react developer, and web developer helping businesses build, fix, and improve SaaS products, web applications, dashboards, internal tools, and client platforms with react, next.js, node.js, supabase, postgresql, API integration, and AI-powered workflows. As a full stack developer, I work across front end and back end development. As a react developer and next.js developer, I build and improve modern web application interfaces, dashboards, admin panels, and client-facing product flows. As a node.js developer, I work on business logic, API integration, authentication, webhooks, oauth, stripe flows, and product functionality that supports real SaaS and web application use cases. My work often combines react, next.js, node.js, javascript, typescript, supabase, and postgresql inside one product. Clients usually hire me when they need a full stack developer who can do more than isolated tasks. They need a react developer who can work inside a real product, a next.js developer who can improve an existing web application, and a node.js developer who can connect front end and back end logic cleanly. I help build MVPs, improve SaaS products, fix broken web applications, stabilize dashboards, extend internal tools, improve client portals, and support existing codebases that need stronger full stack development. A lot of my work is with react, next.js, and node.js products that already exist but need improvement. That can mean bug fixing, maintenance, stabilization, performance improvement, API integration, dashboard development, admin panel development, auth flow fixes, web application cleanup, SaaS feature delivery, or extending an MVP into a more production-ready SaaS platform. I’m comfortable joining an existing codebase and working as a full stack developer, react developer, next.js developer, or node.js developer depending on what the product needs most. I also work with supabase and postgresql when a SaaS product or web application needs database logic, authentication, real-time functionality, role-based access, or cleaner back end structure. In many projects, react, next.js, node.js, supabase, and postgresql work together as the core stack, and that is a stack I’m comfortable building, fixing, and extending. I regularly work on web application and SaaS development that includes API integration, stripe, oauth, webhooks, dashboards, internal tools, and client-facing product flows. As a react developer, I can help build responsive product UI, dashboard UI, admin interfaces, and front end functionality inside larger web applications. As a next.js developer, I can help with product architecture, page flows, performance, routing, feature delivery, and production-ready SaaS implementation. As a node.js developer, I can help with API integration, back end logic, business workflows, third-party services, and server-side product functionality. As a full stack developer, I can connect all of those layers into one working product. I also work with AI when it supports a real SaaS or web application use case. That includes AI integration with OpenAI or Claude APIs, AI-assisted product features, AI workflows inside dashboards and internal tools, and automation that supports web application, SaaS, or client platform functionality. When useful, I can also support web scraping and automation if it fits the product and strengthens a real business workflow. If you need a full stack developer, react developer, next.js developer, node.js developer, or web developer for a SaaS product, web application, dashboard, internal tool, API integration project, MVP, client portal, supabase app, postgresql-based system, or AI-powered product feature, send me a message and I’ll review your project.