Gursimranjit Singh
Verified Expert in Engineering
Software Architect and Full-stack Developer
New Delhi, Delhi, India
Toptal member since April 5, 2022
Gursimranjit is a software engineer and AWS-certified solutions architect and developer with experience building scalable web applications, including performing project analysis, designing architecture, and conducting end testing and deployment. He is passionate about transforming business plans into high-performance working modules. Gursimranjit enjoys testing his code, following clean and best coding practices, and brainstorming ideas before implementing them into code.
Portfolio
Experience
- PostgreSQL - 7 years
- Node.js - 7 years
- React - 7 years
- Amazon Web Services (AWS) - 6 years
- Ruby on Rails (RoR) - 6 years
- JavaScript - 6 years
- AI Agents - 2 years
- ChatGPT Prompts - 2 years
Preferred Environment
Ruby on Rails 5, Node.js, PostgreSQL, React, Amazon Web Services (AWS), Serverless Architecture, Heroku, AI Agents, OpenAI GPT-4 API, Retrieval-augmented Generation (RAG)
The most amazing...
...project I've designed is a complete back-end architecture and DB schema regarding registrations, including multiple payment gateways for payments and refunds.
Work Experience
Back-end Developer
Topkey, Inc.
- Engineered features across a multi-tenant fintech platform handling millions of financial records, reconciling transactions, vendor payments, and owner statements with strict performance and data-isolation guarantees.
- Built AI/LLM-powered workflows for automated transaction categorization and accounting suggestions using vector embeddings, semantic similarity search (Qdrant), and RAG, feedback loops, and evaluation datasets to continuously improve model accuracy.
- Implemented LLM-driven document extraction to parse invoices, statements, and PDFs into structured financial data, reducing manual data entry.
- Integrated 20+ third-party APIs across banking (Plaid, Stripe, Unit.co, Column, and Amex), PMS (Guesty, Hostaway, and Track), and accounting (QuickBooks, NetSuite), designing idempotent, retry-safe background jobs for financial operations.
- Developed responsive, real-time UI with Hotwire (Turbo and Stimulus), ViewComponent, and Tailwind CSS, delivering server-rendered interactivity without a heavy SPA framework.
- Optimized queries on high-volume tables via composite indexing, EXPLAIN-verified pagination, and async job offloading, eliminating N+1S and preventing production timeouts.
- Wrote comprehensive RSpec request/service specs and enforced code quality with RuboCop in a CI-driven workflow.
Full-stack Developer
N.O.N. Administration LLC
- Implemented the user's identity authentication workflow to validate whether the user's identity was valid or not by capturing the front and back of the identity card along with face image recognition.
- Took decisions to set up the project's architecture, including AWS Secrets Manager for secrets, DynamoDB for the data layer, AWS S3 for object storage, and AWS EC2 for application deployment.
- Integrated third-party APIs to validate the user's identity and stored the corresponding results in the AWS DynamoDB and AWS S3.
- Set up the front-end and back-end applications on the EC2 server, including NGINX as a web server. I also put together domain and SSL integrations in the GoDaddy domain registrar and mapped them with the EC2 instance.
Software Engineer
Gartner
- Handled the back-end services, including database designing and AWS architecture.
- Integrated the recommendation engine, using AWS serverless architecture for SMBs to make the right software choice.
- Automated basic/daily used workflows by different stakeholders to remove their dependency on reaching out to devs for their requirements so that they can do their tasks in click(s).
- Contributed to the CircleCI pipeline to set up better development practices and testing strategies in the team.
Software Engineer
Metadesign Solutions Pvt Ltd
- Supervised and owned the responsibilities of driving modules and OKRs.
- Experienced upgrading the legacy code to the latest tech stack by following best coding practices, keeping in mind the scope of the project's growth.
- Took responsibility for leading a team of four, including managing the execution and timely delivery of projects and maintaining superior quality of work.
- Developed a portal, enabling users to register to events using multiple payment gateways and used WebSockets to reflect the seat availability on the UI.
- Used WebSockets to create two-way communication between multiple devices.
- Developed a Chrome extension to download a certain number of videos in the background using Web Workers.
Experience
Event Management System
Used WebSockets to reflect the live seat availability count on the UI and AWS for deployments and object storage.
Recommendation and Personalization Engine
I set up the complete AWS serverless architecture to obtain user interactions and train the data model, using AWS Cloudformation, AWS step functions, and AWS Lambda functions.
Chrome Extension
Added a feature that allows users to pause and resume the download process per their requirements.
Eadie-Tech
E-signature on PDF
Education
Master's Degree in Software Systems
Birla Institute of Technology and Science - Pilani, Rajasthan, India
Bachelor's Degree in Computer Engineering
Guru Gobind Singh Indraprastha University - New Delhi, India
Certifications
AWS Certified Developer Associate
AWS
AWS Certified Solutions Architect Associate
AWS
Skills
Libraries/APIs
Node.js, React, REST APIs, Sidekiq, Stripe API, Twilio API, PayPal API, jQuery, Facebook API, Stripe, Shopify API, JSON API, Codat, Plaid API
Tools
Git, Apache Solr, Amazon Elastic Container Service (ECS), Amazon Simple Notification Service (SNS), AWS Step Functions, Mongoose, NGINX, Docker Compose, RSpec, Plaid, Amazon CloudFront, Cloud66, Honeybadger.io, Amazon Simple Queue Service (SQS), AI Prompts
Languages
JavaScript, Ruby, GraphQL, SQL, Python, TypeScript, CSS, HTML5, Python 3, HTML
Frameworks
Ruby on Rails 5, Redux, Ruby on Rails (RoR), Angular, Express.js, Next.js, Material UI, Stimulus
Paradigms
Serverless Architecture, Test-driven Development (TDD), Metaprogramming, Database Design, Microservices
Platforms
Amazon Web Services (AWS), AWS Lambda, Heroku, Docker, New Relic, Amazon EC2, Webflow, Firebase, Google Cloud Platform (GCP)
Storage
PostgreSQL, MySQL, MongoDB, Amazon S3 (AWS S3), Databases, NoSQL, Redis, Elasticsearch, Amazon DynamoDB, JSON
Other
WebSockets, Back-end, APIs, Architecture, Online Ordering, Software Architecture, Webhooks, Algorithms, Technical Architecture, Lambda Functions, Web Development, Online Payments, Performance Optimization, API Gateways, Chrome Extensions, Payment APIs, CCAvenue, Autoscaling, Agile Sprints, Full-stack, Front-end, eCommerce, MERN Stack, Team Leadership, Leadership, Card Payments, Web Project Management, Full-stack Development, Indexing, ACH, Performance, Amazon RDS, Scalability, Cloudflare, Electronic Health Records (EHR), Online Banking, Fintech, AI Tools, Cursor AI, CI/CD Pipelines, API Integration, Ruby Gems, ActiveAdmin, Unit, E-signatures, AI Agents, AgentGPT, Agentic AI, ChatGPT Prompts, OpenAI GPT-4 API, Retrieval-augmented Generation (RAG), Startups, API Design, Artificial Intelligence (AI), Recommendation Systems, LLM Integration, Feature Engineering
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