Shan Kulkarni
Verified Expert in Engineering
Full-stack Developer
Bhopal, Madhya Pradesh, India
Toptal member since June 14, 2022
Shan is a senior full-stack engineer with 10+ years of experience building web, mobile, and back-end systems end-to-end. He works in React, Next.js, and TypeScript on the web; React Native, Swift, SwiftUI, and Kotlin on mobile; and Node.js, Go, and PostgreSQL on AWS, Supabase, and Vercel. He takes Claude Code-built and early-stage apps to production scale, and ships Claude, OpenAI, RAG, and agentic AI features into live products.
Portfolio
Experience
- Stripe - 10 years
- Architecture - 8 years
- Node.js - 8 years
- React - 8 years
- TypeScript - 8 years
- iOS - 6 years
- React Native - 6 years
- Artificial Intelligence (AI) - 2 years
Preferred Environment
React, TypeScript, React Native, Node.js, iOS, Supabase, Next.js, Vercel, Claude, PostgreSQL
The most amazing...
...thing I built is a 400,000-user app with a 0.0001% crash rate, an AI-coaching and personalization system, and enterprise scheduling for Google and Telefónica.
Work Experience
Senior Full-stack Engineer
Aberrant Nature LLC
- Rebuilt the platform from scratch in three months—web, iOS, and Android. Custom Kajabi LMS, Shopify store, and branded mobile apps. Launched to around 500 members with a 5-star iOS rating.
- Wired up Kajabi, Shopify, Supabase, and HubSpot via REST APIs and webhooks so users, payments, badges, and analytics stayed in sync without manual intervention.
- Designed email automations and built a custom HubSpot app to sync Kajabi badge grants to the CRM in real time, automating the member lifecycle end-to-end.
- Added Statsig experimentation and Meta Pixel tracking across both Kajabi and Shopify for continuous measurement and feature rollouts.
- Deployed Supabase Edge Functions, cron jobs, RLS policies, and schema design to handle auto provisioning and store user data shared across Kajabi, Shopify, and HubSpot.
Lead Engineer | Senior Software Engineer
GrowthDay
- Designed and developed the application architecture and system components for a personal growth platform with live coaching sessions serving 400,000 active users.
- Built the mobile (React Native, Swift, and Kotlin modules) and web app (React and Vercel) from the ground up: course library, live coaching, journaling, habit tracking, goal setting, and community features.
- Built the live video conferencing system (WebRTC and Daily.co) for 1-on-1 and group coaching sessions, plus a native video player for on-demand content.
- Tuned the app to a 0.0001% crash rate and consistent 60 FPS across transitions and list rendering. Monitored with Crashlytics and Datadog.
- Scaled live coaching to 10,000+ concurrent viewers without dropping stream quality.
- Shipped Brendon AI, an AI-powered chat and call coaching avatar with personalized recommendations and growth plans. Built an in-house AI feedback engine that surfaces signals for product, marketing, and support teams.
- Built the payments stack: Stripe Connect for coach payouts, Apple Pay, gift subscriptions, and Stripe Checkout.
- Set up Statsig feature gating and A/B testing for safe rollouts, n8n workflows for lifecycle events, and OneSignal push notifications for re-engagement.
- Hired and mentored the mobile team; set code standards, ran reviews, and aligned with execs and product on the delivery roadmap.
- Collaborated with the marketing team to build and ship landing pages to production using Claude Code and Claude.
Senior Full-stack Engineer
Hybrid Poker
- Built the Hybrid Poker platform, a web app for AI-based poker training.
- Architected a serverless back end on AWS: Cognito for auth, Lambda and API Gateway for services, Amazon S3 and CloudFront for asset delivery, and Amplify for CI/CD.
- Built the front end in React and TypeScript with a Node.js back end.
- Developed the subscription system using Stripe, covering recurring billing, plan upgrades, and payment failure handling.
- Set up Google Analytics and Google Ads to track user behavior and measure acquisition performance.
- Built a short-form video content library using Wistia for training lessons.
- Integrated Discord to automatically provision users into the right channels when they subscribed to or upgraded their plan.
Senior Developer
Aicadium Singapore PTE LTD
- Developed a modern, highly-responsive dashboard for the paper industry that leveraged AI algorithms to predict costs accurately.
- Translated designs and wireframes into a flexible, well-structured front-end architecture incorporating reusable components and libraries.
- Collaborated closely with internal and external product and design teams to comprehend product requirements and provided insights on the technical feasibility of UI/UX designs.
Front-end Engineer
GrowthDay
- Led the mobile and web application revamp by rebuilding the app's core pillars from scratch, improving development processes, optimizing the developer experience, and driving enhancements to enable reusability and increase performance.
- Enhanced the app experience and made it production-ready by implementing push notifications, deep linking the app, optimizing application performance, adding crash-reporting, and integrating Apple Pay and Stripe payment systems.
- Worked on different analytics platform integration like Mixpanel, Google Analytics, the Facebook pixel, and AppsFlyer.
Lead Software Engineer
Appointy
- Led the development of a SaaS platform, SaaStack. Designed plug-and-play architecture for back-end, front-end, and mobile apps.
- Contributed to core layers of the architecture, including authentication, roles and rights, licensing, and default libraries.
- Developed new features for SaaStack to support client billing, people management, and reporting using React, React Native, GraphQL, gRPC, Go, and PostgreSQL.
- Enhanced performance, dynamicity, and customization by driving new enhancements, including caching, to reduce load times from 15 seconds to less than a second.
- Contributed to command-line interface tools for the scaffolding app by leveraging Relay as a GraphQL client to eliminate codebase setup times and protocol buffers to generate the Go service codebase, which reduced the setup time by 80%.
- Decreased the development time by 50% and maximized the development flexibility by developing a set of code generation tools based on easy-to-use annotations.
- Worked on improving the developer experience, created developer guides and checklists, and mentored developers to increase their efficiency.
Product Developer
Appointy
- Developed Appointy's multilayered scheduling tool for small to large businesses, with multiple views, time zone support, and multiple payment gateway support for one million users using Angular, Angular Material, and NgRx Store.
- Evaluated libraries and integration tools to reduce development time from a year to a month and designed microservices and micro front-end architecture to help further optimize development.
- Advised and oversaw development for clients by creating user flows, product roadmaps, and features with a team of five developers.
- Created a new product that coordinated fitness classes and restaurant and spa scheduling for Google.
- Built a room conference scheduling system for Telefonica, one of Spain's largest telecom companies, with features for managing rooms, schedule calendars, staffing, and CMS and TMS integration.
Intern
Appointy
- Integrated a Stripe payment system to accept recurring and one-time payments and created a payment monitor system to track and manage the payments.
- Worked on spam email checker, which verified the email existence. It reduced the email bounce rate by 99.9%.
- Reviewed system implementation to get more customer reviews, increasing the review ratio by 20%.
Experience
GrowthDay App
http://www.growthday.comAppointy X
House of Manifestation
https://houseofmanifestation.com/AI Poker Training App
Speak To Freedom CRM
https://speaktofreedomcrm.comGoogle Appointy REWS
Conferencing Portal for Telefonica
SaaStack
Appointy 9
Education
Bachelor's Degree in Computer Science
University Institute of Technology - Bhopal, India
Certifications
Claude Certified Architect Foundations
Anthropic
Skills
Libraries/APIs
React, Protobuf, Stripe, Node.js, Google Analytics API, Stripe API, Mixpanel API, REST APIs, API Development, Stripe Connect, Stripe Connect API, Social Media APIs, OpenAI API, Shopify API, Zod, Playwright, React Native for Web, Google Maps API, D3.js, AWS Amplify, Azure Blob Storage API, Pushwoosh, React Router, Authorize.net, NgRx, jQuery, Google Task Queue, React Redux, Mindbody API, Segment.io, WebRTC, Recharts, Google AdSense, Socket.IO, Webex API, Mixpanel iOS SDK, Claude API
Tools
Git, Google Analytics, GitHub, Expo, Matomo, Stripe Checkout, ChatGPT, Claude, AWS AppSync, n8n, Claude Code, NPM, Figma, Adobe Analytics, TanStack Router, Bubble, Jira, Keycloak, Miro, WebStorm, OneSignal, Sentry, Webpack, Gulp, Fastlane, Reactotron, JSX, Amazon Cognito, Retool, AWS Command Line Interface (CLI), Amazon CloudFront CDN, Mailchimp, Expo.io, Amazon Simple Queue Service (SQS), 3G Transportation Management (3GTMS), Zapier, Claude Agent SDK
Languages
ECMAScript (ES6), TypeScript, Go, JavaScript, GraphQL, HTML, CSS, Swift, Kotlin, HTML5, JavaScript 5, Python
Frameworks
React Native, Next.js, Jest, SwiftUI, Express.js, gRPC, JSON Web Tokens (JWT), Redux, Material UI, NestJS, Tailwind CSS, Agentic Frameworks, Flutter, OAuth 2, MUI CSS, Angular, Angular Material, Bootstrap, Serverless Framework
Paradigms
Agile Software Development, Mobile Development, Rapid Mobile Application Development (RMAD), Mobile App Design, Automation, REST, Microservices, Microservices Architecture, Scrum, Web Architecture, Agile, Responsive Coding
Platforms
Kajabi, Mixpanel, iOS, RudderStack, Vercel, Mobile, Shopify, PostHog, Firebase, Contentful, Android, Amazon Web Services (AWS), AWS Lambda, Amazon EC2, HubSpot, Software Design Patterns, Windows Server, Google Cloud Platform (GCP), Docker, WordPress, LearnWorlds, WooCommerce
Storage
JSON, PostgreSQL, MySQL, Amazon DynamoDB, MongoDB, Datadog, Microsoft SQL Server, Azure Queue Storage, IIS SQL Server, Azure Active Directory, SQL Server 2016, SQL Server 2017, Redis, Amazon S3 (AWS S3), Databases
Other
Architecture, Payment APIs, Development, Web Analytics, Stripe Payments, UI Components, Mobile App Development, Google Tag Manager, Full-stack, Strapi, Responsive UI, OAuth, Artificial Intelligence (AI), Google Analytics 4 (GA4), Responsive Email Templates, API Integration, Full-stack Development, Front-end Development, Analytics, Payment Gateways, Algorithms, Large Language Models (LLMs), Agentic AI, AI Agents, Back-end Development, Supabase Auth, Cloudflare, New Kajabi, AI Integration, Customer Relationship Management (CRM), App Store, Interactive UI, Mobile Apps, Software Architecture, Scalability, Code Auditing, Software Design, Startups, Vibe Coding, Prototyping, AI Tools, Web Scalability, Minimum Viable Product (MVP), Cursor AI, API Gateways, API Design, Progressive Web Applications (PWAs), Bun, Vite, OXC (Oxlint), Resend, GitHub Actions, Storybook, Data Analytics, Greenfield, Apple Pay, User Interface (UI), Web UI, Gatsby, Front-end, WCAG 2, Dashboards, Subscriptions, APIs, Login & Registration, Content Management Systems (CMS), Push Notifications, Location Tracking, Chargebee, Amazon API Gateway, Email Templates, CI/CD Pipelines, SVG, Cloud Infrastructure, Poker, Dropshipping, Video Streaming, Supabase, Amazon Cognito User Pools, Streaming, Videos, AI Avatars, Deno, Reverse Proxy, Distributed Systems, Amazon Bedrock AgentCore, Software Development, WebSockets, NATS, PWA, Documentation, Square, PayPal, TMS, IIS, Serverless, MERN Stack, User Authentication, Cloud Services, AWS Cloud Architecture, Lambda Functions, Data Visualization, Okta, Amazon DocumentDB, Client Relationship Management, Webex, Stacker, Games, Affiliate Programs, Lovable, MVP Design, Production
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