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Senior Full Stack Developer and Technical Lead with 9+ years building secure, production-grade systems across Australian Government and commercial environments. Strong expertise in .NET/C#/Python, REST APIs, SQL, CI/CD, and enterprise integrations with deep experience in authentication/authorization (JWT, ADFS/MSAL) and performance optimization. Currently engineering enterprise AI knowledge assistant and AI engineering products using Python, FastAPI, OpenAI APIs, RAG, vector search, embeddings, agentic workflows, and evaluation/assurance controls (accuracy, retrieval quality, citation fidelity, privacy, bias, prompt injection resistance, and failure handling).…Senior Full Stack Developer and Technical Lead with 9+ years building secure, production-grade systems across Australian Government and commercial environments. Strong expertise in .NET/C#/Python, REST APIs, SQL, CI/CD, and enterprise integrations with deep experience in authentication/authorization (JWT, ADFS/MSAL) and performance optimization. Currently engineering enterprise AI knowledge assistant and AI engineering products using Python, FastAPI, OpenAI APIs, RAG, vector search, embeddings, agentic workflows, and evaluation/assurance controls (accuracy, retrieval quality, citation fidelity, privacy, bias, prompt injection resistance, and failure handling).

VARUN KHANNA

Full Stack Developer, Web Developer, Back-End Developer, +1

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Senior Full Stack Developer and Technical Lead with 9+ years building secure, production-grade systems across Australian Government and commercial environments. Strong expertise in .NET/C#/Python, REST APIs, SQL, CI/CD, and enterprise integrations with deep experience in authentication/authorization (JWT, ADFS/MSAL) and performance optimization. Currently engineering enterprise AI knowledge assistant and AI engineering products using Python, FastAPI, OpenAI APIs, RAG, vector search, embeddings, agentic workflows, and evaluation/assurance controls (accuracy, retrieval quality, citation fidelity, privacy, bias, prompt injection resistance, and failure handling).…Senior Full Stack Developer and Technical Lead with 9+ years building secure, production-grade systems across Australian Government and commercial environments. Strong expertise in .NET/C#/Python, REST APIs, SQL, CI/CD, and enterprise integrations with deep experience in authentication/authorization (JWT, ADFS/MSAL) and performance optimization. Currently engineering enterprise AI knowledge assistant and AI engineering products using Python, FastAPI, OpenAI APIs, RAG, vector search, embeddings, agentic workflows, and evaluation/assurance controls (accuracy, retrieval quality, citation fidelity, privacy, bias, prompt injection resistance, and failure handling).

Available to hire

Senior Full Stack Developer and Technical Lead with 9+ years building secure, production-grade systems across Australian Government and commercial environments. Strong expertise in .NET/C#/Python, REST APIs, SQL, CI/CD, and enterprise integrations with deep experience in authentication/authorization (JWT, ADFS/MSAL) and performance optimization.

Currently engineering enterprise AI knowledge assistant and AI engineering products using Python, FastAPI, OpenAI APIs, RAG, vector search, embeddings, agentic workflows, and evaluation/assurance controls (accuracy, retrieval quality, citation fidelity, privacy, bias, prompt injection resistance, and failure handling).

Skills

Experience Level

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Expert

Intermediate

Intermediate

Language

English

Fluent

Work Experience

Enterprise AI Knowledge Assistant (Independent AI Engineering Product) at Independent

January 1, 2026 - Present

Developing agent and workflow patterns to classify requests, retrieve approved content, generate structured outputs, and route higher-risk actions for human review. Defining an assurance approach covering answer accuracy, retrieval quality, citation fidelity, latency, cost, privacy, bias, prompt injection, adversarial scenarios, and failure handling. Implementing trace audit-by-design through segregation of content, logging, traceability, and explicit operational controls. Built a Python/FastAPI application integrating OpenAI APIs for semantic question answering over enterprise documents with RAG, vector embeddings, and grounded responses with citations.

Technical Lead at Australian Tax Office (ATO)

January 1, 2025 - Present

Led the DPORO (Dynamic Proof of Record Ownership) initiative enabling secure linking of ATO services with MyGov and MyGovID. Owned technical design, development, and implementation, ensuring compliance with ATO security, authentication, and identity verification standards. Coordinated with solution architects, security teams, stakeholders, and external integration teams to deliver a secure and scalable verification solution. Oversaw API integrations between ATO systems and identity management services for real-time verification and account linking. Implemented JWT and certificate-based mechanisms to protect sensitive taxpayer information, and drove production deployments, risk management, performance optimization, and troubleshooting across multiple integrated applications.

Senior Full Stack Developer at Australian Tax Office (ATO)

January 1, 2022 - January 1, 2025

Maintained an authentication and authorization application used by customer-facing ATO applications, integrating multiple APIs and portals with MyGov/MyGovID. Implemented and updated JWT-based security between APIs and portals, applied secure authentication/authorization changes, and delivered front-end updates (Angular/Node/Bootstrap/JS). Wrote PowerShell scripts, handled database/performance improvements (stored procedure and query optimization), and resolved bugs in integration and production using AWS logs. Managed code in GitHub and supported regular deployments via CI/CD pipelines, including performance testing and production support.

Full Stack Developer/Consultant at Attorney General (Dialog IT), Canberra

January 1, 2021 - January 1, 2022

Developed two portals and two web APIs for 'Register for Authorised Person and Warrants' with secure ADFS login for internal and external users (police/judges). Built APIs and portals from scratch using .NET Core (back end) and React (front end), implementing multiple GET/POST methods and integrations with internal/external portals. Delivered continuous deployments/releases each sprint using TFS build/release pipelines and variables. Used DACPAC for database deployment and managed secrets via Azure Managed Identity and Key Vault. Implemented JWT token security for APIs/portals and ADFS/MSAL for web application authentication/authorization.

System Programmer at Brookfield GIS, Sydney

January 1, 2020 - January 1, 2021

Improved system efficiency by setting up cloud infrastructure to remotely monitor fire system panel assets and other electronic equipment. Programmed panels and configured protocols for communication with the web server. Built a fire system web server application showing building overview graphics and real-time alarm status. Supported Agile delivery, maintained code in GitHub with CI/CD pipelines, created/upgraded user interfaces using C# and Python, and created/updated deployment pipelines using YAML.

System Programmer at Honeywell, Sydney

January 1, 2017 - January 1, 2020

Built web server applications to display real-time fire alarm status for buildings. Set up cloud infrastructure for remote monitoring of fire system panels and electronic equipment. Performed hardware/software fault finding and updated firmware. Configured network device setup using Kali Linux and Wireshark for troubleshooting and diagnostics. Supported Agile tasks and maintained code with CI/CD pipelines.

Application Engineer at Micromax Specialist in Automation, Sydney

January 1, 2014 - January 1, 2017

Created web applications enabling client login to remotely monitor sites, machinery, and real-time production data. Provided machine control capabilities (Windows/Mac/Linux) for selected clients and supported IoT-style secure machine-to-machine communication using VPN tunnelling with TLS/secure socket layer. Implemented front-end with HTML/CSS/JavaScript and back-end with Python and Azure cloud. Performed extensive testing/debugging, used Wireshark and Jira, and maintained GitHub code with CI/CD pipelines including deployment workflows.