Abhijeet Kumar
Verified Expert in Engineering
Software Engineer and Developer
Amsterdam, Netherlands
Toptal member since September 23, 2026
Abhijeet is a senior software engineer with 13+ years of experience at Amazon, Zalando, and Rakuten. At Amazon, he architected and led an agentic AI analysis platform for large financial datasets, cutting report review time by 75%, and built a micro-frontend framework adopted by 50+ engineering projects. Abhijeet's expertise spans Java, Node.js, and Python back ends, React/TypeScript front ends, and LLM agents and RAG pipelines on AWS for fintech and compliance.
Portfolio
Experience
- Full-stack Development - 13 years
- Java - 12 years
- React - 8 years
- Node.js - 8 years
- TypeScript - 8 years
- Agentic AI - 2 years
- Agentic RAG Systems - 2 years
- Prompt Engineering - 2 years
Preferred Environment
Docker, MacOS, Java, React, TypeScript, Node.js, Amazon Web Services (AWS), LangChain, Langfuse, Full-stack Development
The most amazing...
...platform I've architected is an agentic AI system at Amazon that cut financial report review time by 75% for accountants and auditors.
Work Experience
Senior Software Development Engineer
Amazon Development Center (Netherlands)
- Architected and led an agentic AI analysis platform embedded in a financial reporting product used by accounting, tax, and audit professionals, cutting report review time by 75%.
- Designed the agent in LangGraph on Amazon Bedrock with a planner, tool-routing runner, and response synthesizer, keeping all data access behind an authenticated tool API with mandatory guardrails.
- Built a two-tier analytics platform serving 200+ tax analysts across 600+ global tax registrations, using Athena over Glue tables plus on-demand OpenSearch drill-down across 250+ columns.
- Led 80% of the implementation of a micro-frontend framework using React, TypeScript, single-spa, and Module Federation, adopted by 50+ projects and saving approximately 120 engineer-days per project.
- Re-architected a tax reporting pipeline processing 20TB per month across 5 EU countries, reducing new-country onboarding from 6 months to 3 weeks.
- Managed the central orchestration service, coordinating ETL, rule validation, and adjustment services across teams. Raised test coverage from 10% to 90% and limited production issues to 3 across 3 major releases.
- Built RAG-based natural-language search over compliance documentation on Amazon Bedrock, mentored an intern into a full-time hire, and received the 2025 Fintech Excellence Award.
Senior Software Development Engineer
Zalando
- Owned end-to-end delivery of the coupon feature on the product detail page for one of Europe's largest fashion eCommerce platforms, from back-end design to web and mobile UI.
- Designed and built the back-end service in Kotlin for the coupon display and apply flow, passing coupon data to the Cart service owned by another team through REST APIs.
- Developed the customer-facing coupon UI for web and mobile and integrated it with the new back-end service.
- Set up the service's Kubernetes deployment, including testing and configuring pod autoscaling, to make it production-ready for high-traffic sales periods.
- Contributed to the A/B testing rollout used to validate the feature's impact on customers before full release.
Senior Software Development Engineer
Rakuten India
- Joined as a founding engineer of a new warehouse management team at a global eCommerce company, turning business requirements into system design and building the product from scratch.
- Built high-performance REST APIs in Java and Spring Boot, sustaining 2,000+ queries per second for warehouse operations.
- Developed 2 production applications almost single-handedly, an internal warehouse management tool and a staff training tool, with React front ends and full ownership from design through deployment.
- Delivered 13 change requests raised during QA within the same cycle, keeping the release date intact while maintaining over 90% test coverage with static analysis (PMD and Checkstyle) and full documentation.
- Introduced React to the team as its only React engineer at the time and trained 2 teammates to work with it independently.
- Received the 2019 Individual Excellence Award and a quarterly performance award for ownership and delivery on both applications.
Full-stack Developer
StoneGrid Technology Solutions (TravelKosh)
- Joined a five-person travel startup as one of its first engineers and built its online travel package booking product from scratch.
- Owned the full stack end to end, including the front end, back-end services, database design, and deployment on Google Cloud Platform.
- Designed the back end as a set of microservices covering package search, booking, and payments, with a relational database schema built for the travel domain.
- Developed and published 5 Android apps for the product on the Google Play Store.
- Worked directly with the founders to turn business ideas into shipped features, handling requirements, design, development, and release without a separate QA or DevOps team.
Software Engineer
MetricStream
- Developed enterprise governance, risk, and compliance applications in Java and the Spring Framework for a leading GRC software company.
- Created a team-wide code review checklist that became the standard for quality checks before release.
- Ran technical knowledge-sharing sessions for the team on Spring and coding practices.
Software Engineer
Robert Bosch Engineering and Business Solutions
- Developed web application features in Java and the Play Framework for internal engineering and business systems at a global technology company.
- Contributed to improving the team's development processes and coding standards.
- Built and optimized SQL queries and database-backed features, working across the front end, back end, and database layers.
- Collaborated with teams in Germany and India to gather requirements and deliver features in an agile, distributed setup.
Experience
AI Support Assistant: RAG-based Reply Recommendations
https://github.com/abhijeet4som1/ai-support-assistantI designed and built the entire product, including a spec-first API modeled in Smithy with a generated server SDK and OpenAPI types, a Fastify back end with an asynchronous worker that parses, chunks, and embeds guideline files into Postgres using pgvector, and a React front end. Answers use RAG on Gemini with structured output, an explicit "not covered" verdict in place of invented policy, and prompt-injection defenses. Agent corrections are reused as few-shot examples and retired when guidelines change.
I added JWT authentication with rotating refresh tokens, Langfuse tracing, offline evaluations with an LLM judge, and 150+ automated tests, all running in Docker Compose.
Education
Bachelor's Degree in Computer Science
Dr M.G.R University - Chennai, India
Associate's Degree in Computer Science
NTTF - Thalassery, Kerala
Certifications
Databricks Certified Generative AI Engineer Associate
Databricks
Skills
Libraries/APIs
Node.js, React, React Redux, React Router, API Development, Pydantic, Claude API, REST APIs, OpenAPI
Tools
Sentry, Jira, Amazon Cognito, AWS Cloud Development Kit (CDK), Amazon OpenSearch, Amazon Simple Notification Service (SNS), Amazon Simple Queue Service (SQS), Grafana, AI Prompts, ChatGPT, Claude, Pytest, Terraform, Claude Code, Codex, Claude Agent SDK, Jenkins, PMD, Checkstyle, NGINX
Languages
Java, TypeScript, JavaScript, HTML5, HTML, CSS, GraphQL, Python, Python 3, Kotlin, SQL
Frameworks
Spring Boot, Redux, Spring Microservice, LangGraph, Agentic Frameworks, Tailwind CSS, Express.js, Django, JUnit, Spring, Play Framework, Fastify, JSON Web Tokens (JWT)
Paradigms
Automated Testing, ACID, Model Context Protocol (MCP), Microservices
Platforms
Oracle, Kubernetes, Docker, MacOS, Amazon Web Services (AWS), Langfuse, Google Cloud Platform (GCP), Android
Storage
Datadog, Elasticsearch, Databases, Redis, MongoDB, MySQL, Data Pipelines, PostgreSQL
Other
CI/CD Pipelines, Full-stack Development, Front-end Development, API Integration, Full-stack, Software Architecture, Code Review, Interviewing, APIs, Integrations, Cloud Platforms, Data Modeling, Architecture, System Integration, Vibe Coding, AI Compliance, AI Security, Compliance, AI Workflow, ChatGPT Prompts, Dashboards, Data Visualization, Kafka, Agentic AI Systems, Agentic RAG Systems, MLflow, Vector Search, Agentic AI, AI Agent Orchestration, AI Agents, Anthropic, Gemini API, AI-assisted Development, Technical Leadership, Artificial Intelligence (AI), AI Integration, AI-generated Code, Team Leadership, Cursor AI, Agentic Coding, AI Engineering, WebSockets, Generative Artificial Intelligence (GenAI), OpenAI, SOAP, Webhooks, Multi-agent Systems, Single Sign-on (SSO), Fintech, RAG Pipelines, Audits, Minimum Viable Product (MVP), AI Governance, Amazon Bedrock, AI Tools, FastAPI, GCP, Spring Framework, LangChain, A/B Testing, Large Language Models (LLMs), Pgvector, Retrieval-augmented Generation (RAG), Google Gemini, Prompt Engineering, Smithy, Vite
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