Sanjeev Kumar

Senior Software Engineer

React Native • React.js • Next.js • Node.js

Building scalable mobile and web applications with 8+ years of experience across Healthcare, AI, SaaS, Retail, and Enterprise products. Passionate about clean architecture, high-performance applications, and exceptional user experiences.

8+ years of experience delivering production-ready mobile and web applications using React Native, React.js, Next.js, Node.js, and TypeScript. Built enterprise solutions across Healthcare, AI, SaaS, E-commerce, and Retail while collaborating with global teams to deliver scalable, high-performance applications.

8+ Years Experience
React Native • React.js • Next.js • Node.js • TypeScript
Healthcare • AI • SaaS • Retail • Enterprise Applications

India • Open to Remote & On-site Opportunities

Download resume View projects LinkedIn Contact Me

Happy to chat over email or LinkedIn — I usually reply within 24 hours

About Me.

Hello — I am Sanjeev

I am a Senior Software Engineer with 8+ years of experience building scalable mobile and web applications using React Native, React.js, Next.js, and Node.js. I enjoy solving complex engineering problems through clean architecture, intuitive user experiences, and maintainable code that scales with business growth.

Over the past 8+ years, I've built production-ready applications across Healthcare, AI, SaaS, E-commerce, Retail, and Enterprise domains. I've worked on everything from mobile architecture and scalable frontend development to backend APIs, performance optimization, and production deployments.

I enjoy translating business requirements into scalable technical solutions—from architecture and API integration to deployment and long-term maintenance. I believe great software is not only functional but also easy for teams to maintain, extend, and scale.

I am open to remote Senior Software Engineer and React Native roles and can join immediately. If you are hiring, I would genuinely love to hear from you— connect on LinkedIn or send a message.

8+ Years Experience

20+ Projects Delivered

6+ Business Domains

Now Immediate Joiner

Industries I have built for

Healthcare AI E-commerce & Retail SaaS & Ed-tech Enterprise & IT Services

Core Expertise

React Native Architecture
Full Stack Development
Performance Optimization
Offline First Applications
Native Modules
REST APIs
Authentication
AI Integrations
State Management
CI/CD

Recent Highlights

Built AI-powered SDLC Platform
Developed Healthcare Applications
Built Enterprise SaaS Products
Delivered E-commerce Applications
Full Stack Development across mobile and web

Engineering Principles

Design scalable, modular architectures.
Build reusable and maintainable components.
Optimize applications for performance and reliability.
Deliver complete features from UI to backend APIs.
Write clean, well-tested, production-ready code.
Collaborate closely with Product, Design, QA, and Backend teams.

Quick facts

RoleSenior Software Engineer
LocationNew Delhi, India
Emailprsanjeev02@gmail.com
Phone+91 7004798516
LinkedIn/in/sanjeev-kumar-02
StatusAvailable immediately

Download Resume

Tech stack

Mobile

React NativeFlutterKotlinRedux

Frontend

React.jsNext.jsTypeScriptRedux

Backend

Node.jsExpressREST APIFirebase

Database & tools

MongoDBMySQLSQLiteGitDocker

Architecture

Mobile ArchitectureSystem DesignPerformanceOffline First

What I am looking for

Looking for opportunities where I can contribute to building scalable products, mentor engineers, solve challenging technical problems, and help teams deliver high-quality software.

Senior Software Engineer
Senior React Native Developer
Full Stack Engineer (React / Node)

Remote or hybrid · India · Start immediately

LinkedIn Say hello

What I bring to a team

React Native at scale

Production apps on Play Store and App Store—Cityfurnish, Kaipsool, Bonkers Corner, and more. Comfortable owning features end to end on Android and iOS.

Full-stack web

React.js, Next.js, and Node.js backends. Dashboards, APIs, auth flows, and integrations that hold up under real traffic.

Team & mentorship

Code reviews, architecture discussions, and mentoring juniors—experienced collaborating with designers, PMs, and QA in remote squads.

Performance & quality

Optimized load times, reusable component libraries, and maintainable codebases—so products feel fast and teams ship with confidence.

Core Expertise.

Where I add the most value on a product team—based on 8+ years shipping mobile and web in production.

React Native · iOS & Android

Feature ownership from UI to release—navigation, state, native modules, store deployments, and performance tuning on real devices.

React.js & Next.js web apps

Dashboards, marketing sites, and authenticated web products with SSR/SSG, API integration, and component libraries teams can reuse.

APIs, auth & integrations

REST APIs, JWT auth, payments, Firebase, MongoDB/MySQL—connecting frontends to backends that behave reliably under load.

Team collaboration

Code reviews, architecture discussions, mentoring juniors, and clear async updates—comfortable in remote, cross-functional squads.

Experience & Skills.

Experience

Senior Software Engineer

WebSharRemote

Tech Stack
React NativeReact.jsNext.jsNode.jsTypeScriptReduxFirebaseREST API

Delivered enterprise-grade React Native and full-stack applications across Healthcare, AI, SaaS, Retail, and E-commerce domains, owning features from architecture and implementation to production deployment.
Delivered AI-powered SDLC platform (Testpunt), Healthcare platform (Atropos Health), and Care Heroes mobile application while leading frontend architecture and full-stack feature development.
Built reusable component libraries and shared modules that improved development consistency and reduced implementation effort across projects.
Integrated secure authentication, payment gateways, push notifications, analytics, and third-party services across Android, iOS, and Web.
Optimized application performance through rendering improvements, efficient state management, lazy loading, and API optimization while mentoring junior developers through architecture discussions and code reviews.

Present Jul 2024
Senior Software Engineer

Aspire Systems Pvt. LtdHybrid

Tech Stack
React NativeReact.jsFirebaseWebRTCREST APITypeScript

Developed enterprise-scale React Native applications for healthcare clients with a focus on scalability, security, and performance.
Built reusable UI components and optimized application architecture to improve maintainability and development efficiency.
Implemented real-time communication features using Firebase and WebRTC while integrating REST APIs and backend services.
Collaborated with distributed engineering teams throughout planning, implementation, testing, and production support.

Jun 2024 Jul 2022
React Native Developer

Cityfurnish Pvt Ltd.On-site

Tech Stack
React NativeReduxFirebaseREST APIPHPMySQL

Developed and maintained the React Native mobile application for a furniture rental platform serving customers across multiple Indian cities.
Built end-to-end e-commerce features including product catalog, cart, checkout, payments, and order management.
Owned Play Store and App Store releases, production deployments, and cross-device compatibility.

Jun 2022 Mar 2021
Software Engineer

Justbooks Solution Pvt. Ltd.On-site

Tech Stack
React NativeReact.jsNext.jsREST APIPayment Gateways

Developed cross-platform mobile applications and web solutions for a book rental platform using React Native, React.js, and Next.js.
Implemented reusable UI components, payment gateway integrations, and REST API communication.
Collaborated directly with stakeholders to understand business requirements and deliver production-ready features.

Feb 2021 Feb 2019
Software Developer

Kreative Digital Solution Pvt. Ltd.On-site

Tech Stack
PHPMySQLJavaScriptHTMLCSS

Developed and maintained PHP/MySQL web applications for enterprise clients.
Built new application features, resolved production issues, and collaborated with senior developers during feature delivery.

Feb 2019 Jan 2018

Coding Skills

Javascript

82%

React Native

80%

Flutter

50%

React.Js / Next.Js

70%

Node.Js

50%

Solidity and BlockChain

60%

HTML/CSS /BootStrap

90%

MongoDB/MySQL

72%

Git/Bitbucket

80%

Education

B.Tech[8.4]

Computer Science and Engineering

Bhagalpur College Of Engineering, Bhagalpur, Bihar

2017 2013
12th Science[75%]

College Of Commerce, Patna, India

2012 2010
10th Math [82%]

Marwari High School, Patna, India

2010 2009

Portfolio.

Selected work from 8+ years in production—mobile apps on Play Store & App Store, and web products in healthcare, e-commerce, and SaaS. See Case Studies for problem → outcome detail.

All
Website
Mobile

Sanjeev Kumar — Testpunt

AI-Powered Software Development Lifecycle Platform
**Stack**: React, Node, VPS, LLM, Playwright, OpenAI

Project Case Studies.

Each project includes the problem, what I built, and the outcome—with live or store links where available. Search by stack (React Native, Next.js) or domain (healthcare, e-commerce, SaaS).

Open to Work.

I am exploring Senior Software Engineer and Senior React Native roles—remote or hybrid in India. If your team needs someone who ships production code and communicates clearly, I would like to talk.

What clients say

Sanjeev is a strong React Native engineer—reliable in production, good at code reviews, and easy to work with across time zones.

Engineering lead

Product company · Remote team

He shipped our mobile flows on time and explained technical trade-offs in plain language—exactly what we needed from a senior engineer.

Product manager

SaaS · India

Strong communication, fast iterations, and production-quality code. He understood our business goals, not just the tickets.

Startup founder

Early-stage SaaS

He fixed performance issues we had ignored for months. The app finally feels like something we can show investors.

Project stakeholder

Mobile & web engagement

Why Choose Me.

Fast delivery

Milestones you can plan around, with visible progress—not endless back-and-forth.

Clean, maintainable code

Readable structure and patterns so the next developer (or you) can ship without fear.

Clear communication

Plain-language updates, honest timelines, and proactive questions before blockers hurt the schedule.

End-to-end support

From UI polish to APIs and deployment—I can own the slice of the stack you need.

Roles I am open to.

Remote or hybrid in India. Notice period: none — available to start immediately.

Senior Software Engineer

Full-time · Remote

End-to-end ownership across React Native and web. Architecture, code quality, and mentoring on growing teams.

Senior React Native Developer

Full-time · Remote

Deep mobile expertise—production releases, performance, native integrations, and cross-platform UX.

Full Stack Engineer

Full-time · Remote

React.js / Next.js frontends with Node.js APIs—ideal for product squads that need one engineer across the stack.

Recruiters & hiring managers

The fastest way to reach me is LinkedIn or email. I am happy to walk through my WebShar work, portfolio projects, and what kind of team fit I am looking for—no pressure, just a honest conversation.

Message on LinkedIn Download resume Email me

UPLOAD SMART CONTRACT

Code snippets.

Let's Code Together

Web3.0 Ecommerce :


    // SPDX-License-Identifier: MIT

    pragma solidity ^0.8.7;
    
    contract Web3Amazon {
        address public owner;
    
        struct Product {
            uint256 ID;
            string name;
            string image;
            uint256 price;
            uint256 rating;
            uint256 stock;
        }
        mapping(uint256=>Product) public products;
    
        struct Order {
            uint time;
            Product product;
        }
        mapping(address=>uint256) public orderCount;
        mapping(address=>mapping(uint256=>Order)) public orders;
    
    
        event List(string name, uint256 price, uint256 quantity);
        event Buy(address buyer, uint256 orderID, uint256 productID);
    
        constructor() {
            owner = msg.sender;
        }
    
        modifier onlyOwner {
            require(msg.sender == owner, "You don't have access to List Products!");
            _;
        }
    
        modifier checkStock(uint256 _stock) {
            require(_stock > 0, "Product is Out Of Stock!");
            _;
        }
    
        function listProduct(
            uint256 _ID, 
            string memory _name, 
            string memory _image, 
            uint256 _price, 
            uint256 _rating, 
            uint256 _stock
        ) public onlyOwner {
            products[_ID] = Product(_ID, _name, _image, _price, _rating, _stock);
            emit List(_name, _price, _stock);
        }
    
        function buyProduct(uint256 _ID) public payable {
            Product memory product = products[_ID];
    
            require(msg.value >= product.price, "Product is Out Of Stock!");
            require(product.stock > 0, "Product is Out Of Stock!");
    
            Order memory order = Order(block.timestamp, product);
            orderCount[msg.sender]++;
            orders[msg.sender][orderCount[msg.sender]] = order;
    
            products[_ID].stock = product.stock - 1;
    
            emit Buy(msg.sender, orderCount[msg.sender], _ID);
        }
    }

Election Voating Smart Contract :


  // SPDX-License-Identifier: MIT

  pragma solidity ^0.8.7;

  contract Election {
      struct Candidate {
          uint id;
          string name;
          uint voteCount;
      }

      mapping(address=>bool) voters;

      mapping(uint=>Candidate) public candidate;
      uint public candidateCount = 0;

      constructor() {
          addCandiate("BJP");
          addCandiate("Congress");
      }

      modifier verifyVoters() {
          require(!voters[msg.sender], "You have alreday done process of voating!!");
          _;
      }

      function addCandiate(string memory _name) private {
          candidateCount++;
          candidate[candidateCount] = Candidate(candidateCount, _name, 0);
      }

      function vote(uint _candidateId) public verifyVoters {
          voters[msg.sender] = true;
          candidate[_candidateId].voteCount++;
      }
  }

Hotel Room Booking Smart Contract :


    // SPDX-License-Identifier: MIT

    pragma solidity ^0.8.8;
    
    contract Hotel {
    
        enum Status { Occupied, Vacent }
        Status currentStatus;
    
        address public owner;
    
        constructor() {
            owner = msg.sender;
            currentStatus = Status.Vacent;
        }
    
        modifier roomStatusModifier() {
            require(currentStatus == Status.Vacent, "Already Occupied!");
            _;
        }
    
        modifier paymentStatusModifier() {
            require(msg.value > 0.01 ether, "You do not have enfough money!!");
            _;
        }
    
        receive() external payable roomStatusModifier paymentStatusModifier {
            payable(owner).transfer(msg.value);
            currentStatus = Status.Occupied;
        }
    }

Upload Image to IPFS Server and share with another address :


    // SPDX-License-Identifier: MIT

    pragma solidity ^0.8.8;
    
    contract Upload {
    
        struct Access {
            address user;
            bool access;
        }
        mapping(address=>string[]) value;
        mapping(address=>mapping(address=>bool)) ownership;
        mapping(address=>Access[]) accessList;
        mapping(address=>mapping(address=>bool)) previousData;
    
        function add(address _user, string memory url) external {
            value[_user].push(url);
        }
    
        function allow(address user) external {
            ownership[msg.sender][user] = true;
            if(previousData[msg.sender][user]) {
                for(uint i=0;i < accessList[msg.sender].length; i++) {
                    if(accessList[msg.sender][i].user == user) {
                        accessList[msg.sender][i].access = true;
                    }
                }   
            } else {
                accessList[msg.sender].push(Access(user, true));
                previousData[msg.sender][user] = true;
            }
        }
    
        function disallow(address user) public {
            ownership[msg.sender][user] = false;
            for(uint i=0;i < accessList[msg.sender].length; i++) {
                if(accessList[msg.sender][i].user == user) {
                    accessList[msg.sender][i].access = false;
                }
            }
        }
    
        function display(address _user) external view returns(string[] memory) {
            require( _user == msg.sender || ownership[_user][msg.sender], "You don't hace access");
            return value[_user];
        }
    
        function shareAccess() public view returns(Access[] memory) {
            return accessList[msg.sender];
        }
    }

Fund Me :

  PriceConvertor.sol

    // SPDX-License-Identifier: MIT
    pragma solidity ^0.8.0;

    import "@chainlink/contracts/src/v0.8/interfaces/AggregatorV3Interface.sol";

    library PriceConvertor {
      function getPrice() internal view returns(uint) {
          // ABI
          // Address 0xD4a33860578De61DBAbDc8BFdb98FD742fA7028e
          AggregatorV3Interface priceFeed = AggregatorV3Interface(0xD4a33860578De61DBAbDc8BFdb98FD742fA7028e);
          (,int price, , ,)=priceFeed.latestRoundData();
          return uint(price*1e10);

      }

      function priceConversionRate(uint ethAmount) internal view returns(uint) {
          uint ethPrice = getPrice();
          // 3000_000000000000000000 = ETH / USD Price
          // 1_000000000000000000 = ETH
          uint ethPriceInUsd = ( ethAmount * ethPrice ) / 1e18;
          return ethPriceInUsd;

      }

      function getVersion() internal view returns(uint) {
          AggregatorV3Interface priceFeed = AggregatorV3Interface(0xD4a33860578De61DBAbDc8BFdb98FD742fA7028e);
          return priceFeed.version();
      }
    }


  FundMe.sol

    // SPDX-License-Identifier: MIT

    pragma solidity ^0.8.0;

    import './PriceConvertor.sol';

    contract FundMe {
      using PriceConvertor for uint;

      uint public mimimumUsd = 10 * 1e18; // 1000000000000000000 ETH
      address[] public funders;
      mapping(address=>uint) public funderAddressToPrice;

      address public owner;

      constructor() {
          owner = msg.sender;
      }


      function fund() public payable {
          // want to send minimum USD for fund
          // require(priceConversionRate(msg.value) > mimimumUsd, "don't have enfough amount");

          // with library we need to call something like below
          // require(priceConversionRate(msg.value) > mimimumUsd, "don't have enfough amount"); // or
          require(msg.value.priceConversionRate() > mimimumUsd, "don't have enfough amount"); // here bydefault msg.value is first paramter if we need to send second Params use msg.value.priceConversionRate(234)

          funders.push(msg.sender);
          funderAddressToPrice[msg.sender] = msg.value;
      }

      function withdraw() public _onlyOwner {
          for(uint fundIndex = 0; fundIndex < funders.length; fundIndex++) {
              address funder = funders[fundIndex];
              funderAddressToPrice[funder] = 0;
          }
          funders = new address[](0);

          (bool callSuccess, ) = payable(msg.sender).call{ value : address(this).balance}("");
          require(callSuccess, "Transfer Failed");
      }

      modifier _onlyOwner() {
          require(owner == msg.sender, "Your are not owner!");
          _;
      }

      receive() external payable {
          fund();
      }

      fallback() external payable {
          fund();
      }
    }

Parent Diseases Payable Smart Contract :


    // SPDX-License-Identifier: MIT

    pragma solidity ^0.8.7;
    
    contract Donation {
        address owner;
        uint balance;
        bool isDiseases;
    
        constructor() payable {
            owner = msg.sender;
            balance = msg.value;
            isDiseases = false;
        }
    
        address payable[] walletAddress;
        mapping(address => uint) inheritance;
    
        modifier onlyOwner() {
            require(owner == msg.sender, "You don't have access to Set Inheritance!!");
            _;
        }
    
        modifier verifyDiseases() {
            require(isDiseases == true, "You don't have any Diseases!!");
            _;
        }
    
        function setInheritance(address payable _walletAddress, uint _amount) public onlyOwner{
            walletAddress.push(_walletAddress);
            inheritance[_walletAddress] = _amount;
        }
    
        function payout() private verifyDiseases {
            for(uint i=0; i < walletAddress.length; i++) {
                walletAddress[i].transfer(inheritance[walletAddress[i]]);
            }
        }
    
        function hasDiseases() public onlyOwner {
            isDiseases = true;
            payout();
        }
    }

Contact Me.

Let's connect

I am actively looking for my next role as a Senior Software Engineer or Senior React Native Developer. If you are hiring—or know someone who is—I would really appreciate an intro.

prsanjeev02@gmail.com LinkedIn profile

Download resume

Available immediately · Remote-friendly · New Delhi, India · GitHub

Sanjeev Kumar

Sanjeev Kumar

About Me.

Hello — I am Sanjeev

Industries I have built for

Core Expertise

Recent Highlights

Engineering Principles

Quick facts

Education

Tech stack

What I am looking for

What I bring to a team

React Native at scale

Full-stack web

Team & mentorship

Performance & quality

Core Expertise.

React Native · iOS & Android

React.js & Next.js web apps

APIs, auth & integrations

Team collaboration

Experience & Skills.

Experience

Senior Software Engineer

WebSharRemote

Senior Software Engineer

Aspire Systems Pvt. LtdHybrid

React Native Developer

Cityfurnish Pvt Ltd.On-site

Software Engineer

Justbooks Solution Pvt. Ltd.On-site

Software Developer

Kreative Digital Solution Pvt. Ltd.On-site

Coding Skills

Javascript

React Native

Flutter

React.Js / Next.Js

Node.Js

Solidity and BlockChain

HTML/CSS /BootStrap

MongoDB/MySQL

Git/Bitbucket

Education

B.Tech[8.4]

Computer Science and Engineering

Bhagalpur College Of Engineering, Bhagalpur, Bihar

12th Science[75%]

College Of Commerce, Patna, India

10th Math [82%]

Marwari High School, Patna, India

Portfolio.

Testpunt

Atropos Health

Care Heroes

GrabMomos

PVC Wallet

PVC Trading

Bonkers Corner

Kaipsool Plus

Screen Film Studios

PVC Wallet

Laxmi-M

BPSC Master

PVC Trading

Build My Home

Screen Film Studios

Phoenix Classroom

Kaipsool

DeQRGids

My Phone - Rejoin

Cityfurnish - Rent Furniture & Appliances

Laxmi-M

Pattan Shetti

Bonkers Corner

IOT API Lab

Kaipsool Plus

KickStart

Laxmi-M