Kapil Goyal
Verified Expert in Engineering
Full-stack Software Engineer and Developer
Greater Noida, Uttar Pradesh, India
Toptal member since August 18, 2026
Kapil is a full-stack software engineer with 13+ years of experience building scalable SaaS, healthcare, fintech, and marketplace platforms. He specializes in Ruby on Rails, React, Next.js, PostgreSQL, and AWS, with a strong focus on API design, system architecture, performance optimization, and cloud-native applications. Kapil has led distributed teams and delivered business-critical products used by global customers.
Portfolio
Experience
- Full-stack - 13 years
- Ruby on Rails - 12 years
- System Design - 10 years
- AWS IoT - 10 years
- Payment Gateways - 9 years
- Mobile Development - 7 years
- React Native - 6 years
- Claude - 2 years
Work Experience
Senior Full-stack Developer
Freelance Clients
- Architected and delivered 15+ production web and mobile applications using Ruby on Rails, React, React Native, PostgreSQL, AWS, and Docker, supporting diverse business workflows across software, healthcare, and real-estate domains.
- Led and mentored distributed engineering teams of up to 10 developers, coordinating sprint planning, code reviews, technical decisions, delivery timelines, and production releases.
- Migrated and upgraded legacy Ruby on Rails applications across major framework versions, modernizing dependencies, front-end architecture, asset pipelines, and database integrations while minimizing production disruption.
- Designed and implemented scalable REST APIs and back-end services in Ruby on Rails, integrating 3rd-party platforms including Stripe, SendGrid, Meta/Facebook Graph API, payment services, and other external APIs.
- Developed subscription, billing, invoicing, accounting, booking, inventory, and role-based access workflows with PostgreSQL transactions and validation logic to maintain data consistency across complex business operations.
- Built and optimized React, Next.js, and React Native applications, creating reusable components and API-driven interfaces that reduced front-end development effort and improved consistency across products.
- Integrated AI capabilities using OpenAI, Claude, large language model (LLM)-based APIs, and AI automation workflows to enhance application functionality, content processing, developer productivity, and business automation.
Senior Full-stack Developer
Bittern Technologies
- Led the development of SaaS, healthcare, fintech, marketplace, and enterprise applications for global clients.
- Architected scalable back-end systems using Ruby on Rails and PostgreSQL.
- Developed modern front ends using React and Next.js.
- Designed and maintained AWS, Azure, and Heroku cloud infrastructure.
- Delivered Android and iOS mobile solutions and API integrations.
- Utilized AI tools, including ChatGPT and Claude, to improve development productivity.
- Worked directly with international clients, founders, and stakeholders.
- Improved API response times by 40% through PostgreSQL query optimization and Redis caching.
- Delivered 10+ production SaaS applications used by international clients across healthcare, fintech, and eCommerce domains.
Ruby on Rails Developer
Flexsin
- Developed healthcare and wellness applications using Ruby on Rails.
- Optimized PostgreSQL and MySQL databases to improve application performance, query efficiency, and scalability.
- Implemented responsive user interfaces that deliver seamless experiences across desktop, tablet, and mobile devices.
- Participated in Agile delivery processes, including sprint planning, daily stand-ups, reviews, and retrospectives.
Software Developer
Startupter Pvt. Ltd.
- Built cloud-based web applications using Ruby on Rails, PostgreSQL, and AWS to deliver scalable and reliable solutions.
- Developed job portal applications using Ruby on Rails, enabling candidate management, job listings, and recruitment workflows.
- Created social commerce platforms using Ruby on Rails, integrating product catalogs, user engagement, and online purchasing features.
Project History
Therapia
https://therapiasoftware.com/My responsibilities included designing RESTful APIs, implementing secure authentication and role-based access control, optimizing database performance, and building responsive user interfaces for providers and administrators. I also managed background processing with Sidekiq, cloud deployment, and CI/CD workflows to ensure reliability, scalability, and maintainability.
The platform was built to support thousands of users across multiple practices, helping healthcare providers streamline operations, improve scheduling efficiency, and deliver a seamless telehealth experience.
Shopstar
https://www.shopstar.co.zaMy responsibilities included implementing eCommerce workflows, payment and shipping integrations, product and order management features, database optimization, and performance improvements to support a growing merchant ecosystem. I also worked with PostgreSQL, Redis, AWS, and modern front-end technologies to enhance application reliability, scalability, and user experience.
The platform was designed to help businesses launch and operate online stores efficiently while supporting secure transactions, operational automation, and multi-channel commerce experiences for South African merchants and creators.
Alliv
My responsibilities included building RESTful APIs, developing responsive and interactive user interfaces, implementing authentication and authorization workflows, optimizing database queries, and integrating third-party services. I also contributed to cloud deployment, performance tuning, and CI/CD automation to ensure reliable releases and maintainable infrastructure.
The platform was designed to support high user engagement, real-time collaboration, and efficient business operations while maintaining strong performance, security, and scalability standards.
Vigoroom
https://vigoroom.comMy responsibilities included implementing user authentication, subscription and payment workflows, appointment and class scheduling, notification systems, and performance optimization for high-traffic operations. I also worked on database design, background job processing with Sidekiq, and CI/CD automation to improve reliability, scalability, and maintainability.
The platform was designed to streamline wellness operations, enhance customer engagement, and provide a secure and responsive experience across desktop and mobile devices.
Lookout4deals
I contributed to the Ruby on Rails back end, API development, deal aggregation workflows, search and filtering features, database optimization, and responsive web interfaces, helping improve platform scalability, reliability, and overall user experience.
Education
Postgraduate Degree in Advanced Computing
CDAC – Institute for Advanced Computing & Software Development - Pune, India
Bachelor's Degree in Electronics Engineering
Shivaji University - Kolhapur, India
Certifications
Process to use UIW, UIE generated code and ensure Quality
Builder University
Managing Customer Repositories – FAQs
Builder University
Skills
Libraries/APIs
React, Node.js, Sidekiq, REST APIs, Stripe, Shopify API, Stripe API, API Development, Liquid, Socket.IO, Google Maps, Claude API, Stripe Connect API, SendGrid API, Twilio API, WebRTC, Google Maps API, OpenAI API, FFmpeg, React Redux, React Router, Google Calendar API, React Query, Facebook API, Instagram API, SQLAlchemy, Intercom API, Vue, Vue 3
Tools
GitHub, Bitbucket, Plaid, Xcode, RSpec, RubyMine, Amazon CloudWatch, GitLab CI/CD, Google Analytics, Shopify Plus, Amazon Simple Notification Service (SNS), Git, Jira, TestFlight, Claude Code, Figma, Webpack, SendGrid, Odoo, Expo, Firebase Authentication, Codex, AI Prompts, Firebase Cloud Messaging (FCM), NGINX, Facebook Ads Manager, Jenkins, ChatGPT, Claude, AWS Copilot, Amazon Simple Queue Service (SQS), n8n
Languages
JavaScript, TypeScript, Ruby, PHP, C, C++, HTML5, CSS3, Python, SQL, CSS, HTML, Go, GraphQL, Liquid Template, Shopify Liquid, Swift, JavaScript 6, Java
Frameworks
Next.js, Bootstrap, Ruby on Rails 7, React Native, Ruby on Rails (RoR), Tailwind CSS, Angular, Redux, OAuth 2, Django, Payload CMS, Selenium, Express.js, NestJS, Laravel, Django REST Framework, Serverless Framework, AngularJS, SwiftUI, UIKit, Flask, Scrapy, Nuxt 3, Nuxt.js
Paradigms
Agile, Scrum, Microservices Architecture, Mobile Development, Unit Testing, API Architecture, Microservices, HIPAA Compliance, Database Design, Search Engine Optimization (SEO), Automated Testing, Automation, Role-based Access Control (RBAC), Web Application Architecture, Real-time Systems, Clean Code, UI Design, Asynchronous Programming, Back-end Architecture, Fast Healthcare Interoperability Resources (FHIR), ACID, Continuous Delivery (CD), Continuous Integration (CI), Model View ViewModel (MVVM), REST, Best Practices, Model Context Protocol (MCP), DevOps
Platforms
Azure, Heroku, Android, iOS, Twilio, Docker, Amazon Web Services (AWS), Shopify, AWS Elastic Beanstalk, AWS IoT, Google Cloud Platform (GCP), Vercel, AWS Lambda, Web, Google Ads, Kustomer, Firebase, Mobile, WordPress, Linux, Oracle
Storage
PostgreSQL, MySQL, MongoDB, Redis, SQLite, Database Management Systems (DBMS), JSON, Elasticsearch, Databases, Cloud Deployment, Data Pipelines, Amazon S3 (AWS S3), Database Architecture, Database Performance, Relational Databases, Database Migration
Industry Expertise
Project Management, Web Design, Healthcare, Insurance
Other
Ruby on Rails, GitHub Actions, Payment Gateways, CI/CD Pipelines, System Design, ARM Architecture, Operating Systems, Ruby on Rails 8, UnityFi, Financials, Repository Management, Customer Repository Workflows, Documentation, Knowledge Base Management, Process Optimization, Code Quality Assurance, Software QA, Front-end Development Workflows, Simulators, Full-stack Development, Full-stack, APIs, Artificial Intelligence (AI), API Design, API Documentation, API Integration, LLM Integration, Responsive UI, SaaS, Application Security, AI Integration, Front-end Architecture, Software Design, Back-end Development, Shopify Customizations, Enterprise Resource Planning (ERP), eCommerce, Electronic Health Records (EHR), Healthtech, HIPAA, Back-end, OAuth, Google Analytics 4 (GA4), Authentication, Authorization, Data Modeling, Query Optimization, User Interface (UI), Front-end, Software Architecture, Solution Architecture, System Architecture, Shopify Design, Front-end Development, Web Development, Large Language Models (LLMs), ChatGPT API, Webhooks, Payment APIs, Payments, Websites, AI Chatbots, Chatbots, Agentic AI, Microsoft Azure, Security, Cloud Security, role based access control, FastAPI, OpenAI, Distributed Systems, Third-party Integration, Web Applications, Identity & Access Management (IAM), Multi-tenant SaaS, Memoization, Performance Optimization, Mobile App Development, App Store, Mobile Apps, Apps, Cloud Infrastructure, Open Source, WebSockets, Workflow, AI Architecture, Startups, RAG Systems, Retrieval-augmented Generation (RAG), Technical Leadership, Development, CMS, Content Management Systems (CMS), Google SEO, User Authentication, Push Notifications, Bug Fixes, CRM, Customer Relationship Management (CRM), Workflows, CRM Implementation, Architecture, RESTFul APIs, Real-time Communication (RTC), Real-time Data, Cloud Architecture, Chrome DevTools, Web Standards, RESTful Microservices, Data Encryption, Speech-to-Text (STT), Third-party APIs, Browser Automation, Bots, Workflow Automation, Integrations, Agentic Workflow Design, Application State Management, User Experience (UX), Integration, Workflow Automation & System Integration, Landing Pages, Web Marketing, Affiliate Marketing, Data Privacy, Access Control, Analytics, Code Review, Cloud, LLM Agents, Conversational AI, Server-side Rendering (SSR), SQLModel, Email, Email Deliverability, AI Tools, Debugging, Optimization, Performance, Data Accuracy & Reporting, Intuit QuickBooks, Generative Artificial Intelligence (GenAI), Text-to-Speech (TTS), Software as a Service (SaaS), Communication, Data Extraction, Privacy, Reporting, Reports, Finance, Financing, Google Play Store, Message Queues, Minimum Viable Product (MVP), Shopify Theme, Mobile App Security, AI-generated Code, Healthcare Software, AI Workflow, ChatGPT Prompts, AI Engineering, Agentic Coding, Concurrency, Database Optimization, Scripting, Multi-tenant Architecture, Mathematics, Statistics, Applied Mathematics, Leadership, Agentic AI Systems, Data Security, Design Systems, System Integration, Calendars, SQL Server, Web Scraping, App Store and Google Play releases, Offline Data Synchronization, REST API integration, React Native with Expo (EAS Build and Update), camera and photo capture, offline-first local storage and sync (SQLite or WatermelonDB), signature capture, App Store Acceptance Process, CRM developer, Health, Instagram, Meta Ads, Facebook Ads, Instagram Ads, Shopify Admin, Cross-functional Team Leadership, Team Leadership, Data Engineering, Tailwind UI, Single-page Applications (SPAs), AI Systems, Large Language Model Operations (LLMOps), Software Engineering, Video Streaming, Streaming, Scraping, Cloudflare, Real Estate, Website Data Scraping, Component-based Architecture, Compliance, Data Scraping, Encryption, Web Application Design, Billing, Pipelines, Anthropic, Data Structures, AI-assisted Development, Cursor AI, Amazon API Gateway, Zustand, AI Automation, AI Agents, General Data Protection Regulation (GDPR), GDPR, Orchestration, Electronics, Physics, UIW, User Interface Engineering (UIE), Generated Code Integration
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