Available for freelance & contracts

I'm Harsh Kankariya,
a backend systems engineer.

Building production-grade microservices, AI-powered pipelines, and scalable backend systems. 1.5+ years shipping real software at Avalara — now open to freelance and contract work in Java, Spring Boot, Node.js, Python, and .NET ecosystems.

Work with me View Resume GitHub

1.5yr

Production experience

1000+

DSA problems solved

Top 4%

LeetCode Knight

10+

Countries served (Avalara)

// work history

Where I've Worked

Avalara

Jan 2025 – Mar 2026
Pune & Bangalore

Software Development Engineer

Architected Content-Consumer microservice (Spring Boot) processing 1–5 GB taxonomy files from AWS S3 using Factory & Strategy patterns — supports 10+ countries with zero core-code changes per mandate.
Built JPA/Hibernate batch curation pipeline into PostgreSQL; achieved 90%+ SonarQube coverage generating mandates, code lists, and specifications.
Implemented Redis token caching (7-day refresh / 15-min access) with 95% cache hit rate; deployed on AWS ECS via Docker with Prometheus monitoring.
Refactored batch jobs to parallel execution using Node.js Worker Threads + BullMQ — cut runtime from 60 → 10 min (6×) and deployment failures by 35%.
Built Node-RED orchestration pipelines coordinating file ingestion, format conversion, VAAS validation, and downstream integration across 10+ mandates.
Configured GitLab CI/CD with quality gates; resolved 15+ production issues/month as on-call, cutting MTTR by 20%.

JavaSpring BootNode.js RedisPostgreSQLAWS ECS DockerNode-REDGitLab CI/CD

Veerbhadreshwar Trust

Apr 2026 – Present
Remote, India

Software Engineer (Freelance)

Building Field Survey & Grievance Portal — full-stack platform serving field agents, supervisors, admins, and citizens; Spring Boot + PostgreSQL with role-based JWT auth.
Implemented QR-code citizen login — QR scan links villagers directly to grievance forms; designed RESTful APIs for survey creation, assignment, and status tracking.
Designed multi-role access control with JWT access/refresh tokens; admin dashboard for real-time survey monitoring across villages.

Spring BootPostgreSQL JWTReactREST APIs

// open to

What I Can Build for You

⚙️

Backend APIs & Microservices

Spring Boot, Node.js, FastAPI, .NET — REST, JWT auth, PostgreSQL/MongoDB, Redis caching, production-ready.

🤖

AI / RAG Integration

LLM-powered features, RAG pipelines, LangChain, OpenAI API, FAISS vector search — chat, Q&A, document intelligence.

☁️

Cloud & DevOps Setup

AWS (S3, ECS), Docker, GitLab CI/CD, Kubernetes — containerize, deploy, monitor your app end-to-end.

🔧

App Maintenance & Fixes

Bug fixes, performance tuning, refactoring legacy code, API integration, dependency upgrades.

📊

Automation Pipelines

Node-RED, BullMQ, cron jobs, file processing — automate repetitive workflows and data pipelines.

🌐

Full-Stack Web Apps

React frontend + Spring Boot / Node.js backend — dashboards, portals, admin panels, SaaS MVPs.

// builds

Projects

RAG GitHub Assistant

AI / Backend

Agentic RAG system that ingests entire GitHub repos via semantic chunking, stores embeddings in FAISS, and answers natural-language questions with file-level citations.

✦ 85%+ answer relevance ✦ File-level citations

PythonFastAPILangChain FAISSOpenAI

Field Survey & Grievance Portal

Production

Production full-stack platform for an NGO serving rural India — QR-code citizen login, multi-role dashboard, real-time grievance tracking across villages.

✦ Live production ✦ 4 user roles

Spring BootReactPostgreSQLJWT

Life Log

Full-Stack

Social memory platform with JWT access/refresh auth, activity feed, image uploads, likes/comments. Indexed MongoDB queries for efficient pagination and full-text search.

✦ Refresh token flow ✦ Full-text search

ReactNode.jsMongoDBJWT

Content-Consumer Microservice

Enterprise · Avalara

High-throughput Spring Boot microservice processing 1–5 GB tax taxonomy files from AWS S3. Factory + Strategy patterns support 10+ countries with zero core-code changes per mandate. Redis token caching hit 95% hit rate.

✦ 10+ countries ✦ 95% cache hit rate ✦ 90%+ test coverage

JavaSpring BootAWS S3RedisPostgreSQLDocker

Node-RED Orchestration Pipeline

Automation · Avalara

Node.js orchestration system coordinating file ingestion, format conversion, VAAS validation, tax calculation, and downstream microservice integration across 10+ country mandates. Parallel Worker Threads + BullMQ cut runtime from 60 → 10 min.

✦ 6× faster runtime ✦ 35% fewer deploy failures

Node.jsNode-REDBullMQWorker ThreadsAWS S3

// side contributions

Freelance & Open Contributions

Field Survey & Grievance Portal — Veerbhadreshwar Trust

Full-stack production platform for an NGO — QR-code citizen login, multi-role dashboard (field agents, supervisors, admins, citizens), real-time grievance tracking across villages. Spring Boot + React + PostgreSQL with JWT RBAC.

Spring Boot · React · PostgreSQL

REST API Integration — WhatsApp Notification Service

Built a Spring Boot service that hooks into an existing client backend to send templated WhatsApp notifications via Meta's Cloud API — order confirmations, OTPs, and delivery updates.

Java · Spring Boot · Meta API

FastAPI Chatbot Backend — College FAQ Bot

Built a RAG-powered FAQ chatbot for a college admission portal — PDF ingestion, FAISS vector search, OpenAI completions, and a FastAPI backend with streaming responses.

Python · FastAPI · RAG · OpenAI

React + Node.js — E-commerce Dashboard for Local Business

Built a small inventory and order management dashboard for a local retailer — product CRUD, order status tracking, and a simple analytics view. Deployed on Vercel + Railway.

React · Node.js · MongoDB

Codebase Maintenance & Dependency Upgrades

Ongoing maintenance for a startup's Spring Boot monolith — upgraded Spring Boot 2.x → 3.x, resolved breaking changes, fixed Hibernate 6 migration issues, and added missing unit tests.

Java · Spring Boot · JUnit

// tech stack

Skills

languages

Java Python JavaScript C++ TypeScript

backend & frameworks

Spring Boot Node.js FastAPI Express.js .NET (open to) REST APIs Microservices

databases

PostgreSQL MongoDB Redis MySQL

ai / ml

LangChain RAG OpenAI API FAISS MCP Prompt Engineering

cloud & devops

AWS S3 AWS ECS Docker Kubernetes GitLab CI/CD GitHub Actions Terraform

security & auth

JWT OAuth 2.0 RBAC Secure API Design