UI Lead - React.js

ReactNative ● Proficient in React, JavaScript (ES6+), and TypeScript. ● Expertise in state management libraries (Redux, Zustand, etc.). ● Hands-on experience with react-navigation and deep linking. ● Solid understanding of Expo (both managed and bare workflows). ● Knowledge of native development (Swift/Objective-C for iOS, Java/Kotlin for Android). ● Experience with custom native module bridging and native UI integration. ● Strong debugging skills using tools like Flipper and Chrome DevTools. ● Familiarity with Jest, React Native Testing Library. ● Experience with REST APIs, GraphQL, and real-time data (WebSockets). ● Ability to manage OTA updates with EAS Update and configure EAS Build. ● Experience in app publishing and release lifecycle on both Play Store and App Store. ● Knowledge of secure storage, token handling, and app-level security practices. 

JD: React Frontend Engineer (Web)

Role: React Engineer – Real-Time Web Applications

We are building data-intensive, real-time web applications. We need engineers who can handle dynamic data, performance constraints, and complex UI states at scale.

What You’ll Do

• Build scalable frontend systems using React
• Handle real-time data flows (WebSockets, streaming updates)
• Optimize rendering performance for high-frequency updates
• Build reusable component systems and state management
• Work closely with backend teams on API design
• Ensure observability (logging, error tracking, performance metrics)

Must-Have Skills

• Strong experience in React (hooks, state management)
• Experience with:
• Real-time data handling
• Large datasets / dynamic UI
• Performance optimization:
• Memoization, virtualization, rendering control
• Solid understanding of:
• Browser performance
• Network behavior

Good-to-Have

• Experience with dashboards / analytics tools
• Experience in streaming or content platforms
• Familiarity with WebRTC or RTC integrations
• Experience with SSR (Next.js)

What We Value

• Ability to handle high-frequency UI updates without lag
• Strong debugging and profiling mindset
• Clean architecture and reusable design systems

We build the best of commerce tools for brands across India. We power commerce for some of the top brands like Levis, boAt, Birkenstock, Kohler and lot more. We are looking for a rockstar Reactjs developer to join us and build the best of tools to empower the largest brands of India.

1. 3-5 years of experience in front-end development with React.js.
2. Strong proficiency in JavaScript (ES6+), TypeScript (preferred).
3. Hands-on experience with Redux, Context API, or Zustand.
4. Good understanding of RESTful APIs, GraphQL, and WebSockets.
5. Experience with front-end build tools (Webpack, Babel, Vite, etc.).
6. Knowledge of CSS frameworks like TailwindCSS, Bootstrap, Material UI.
7. Familiarity with unit testing (Jest, Cypress, React Testing Library).
8. Experience with Git, GitHub, and CI/CD pipelines.
9. Ability to work in an Agile development environment.
10. Strong problem-solving skills and attention to detail.

Responsibilities

Develop high quality, secure, stable code for use in products and solutions for

customers, making it easier for other developers to maintain, enhance, reuse,

and localize

Work with Product Owner and/or Product Manager/Team to understand and help

refine functional requirements for new products

Develop and outline architecture and relationships between subsystems and

participates in review of those designs

Investigate and, if necessary, prototype technologies and algorithms relating to

the task

Break down a large problem into smaller components and provide a clear

solution for each piece

Ensure new code, feature or software product meets performance goals/metrics

Research external best practices and emerging technologies for possible

incorporation into company products and methodologies

Write and maintain the code following Test-Driven-Design principles

Minimum Qualifications

Bachelor’s degree in any Engineering discipline from reputed engineering

college

5 to 7 years of strong programming skills in Web and Cloud Technologies

Should have a very strong foundation in JavaScript, and must have a clear

understanding of basic web fundamentals such as prototype based inheritance,

scopes, Event Loop, Memory Management in JS, etc

Should be good at developing modular front-end applications and is expected to

have the knowledge to create good abstractions that can be reused . Should also

have in-depth understanding of latest ES6 standards such as spread operators,

arrow functions, etc

Should have strong programming skills in Web and Cloud Technologies

Should be strong in OOAD Concepts

Should have a strong hands-on in React, Typescript

Should have Hands-on experience in any of the backend language.

Should understand latest paradigms in Front End Development such as Pub-Sub

Pattern, Redux, RxJS, Service Workers, Client Caching, Lazy Loading, Dynamic

Injection, Bundle Optimisation, etc

Should have very good hands-on knowledge of CSS3 & HTML5

Should have good knowledge of Postman API Platform

Should have experience with Amazon web services – ECS, Lambda, S3, SQS, etc

Should have Hands-on experience of developing RESTful web services and

integrating the same with heterogeneous clients

Should have Hands-on experience with Relational or NoSQL Database’s

Should have a very clear understanding of TDD is expected and should have

good exposure to writing UT's and designing UI components with testability in

mind

Should have Strong Communication and Analytical skills

Flexibility under changing conditions and the ability to multi-task between

projects

Preferred Qualifications

Hands-on experience with C++

Nice to have experience with Python

Nice to have experience with CI/CD tools like Docker, Jenkins, etc

Nice to have a hands-on & Understanding of CSS Pre-processors such as SASS,

LESS, etc

• 2-4 years of work experience, preferably in a startup
• An engineering degree preferably, from a top-tier school (or equivalent experience)
• Hands-on experience in the JavaScript ecosystem, libraries, and tooling (ES6/7), React.js, and Redux
• Knowledge of React Hooks is an added advantage.
• Expert knowwledge of HTML/CSS, web standards, best practices
• Good understanding of asynchronous request handling, partial page updates, and AJAX
• An experience of writing clean, well documented, semantic code with responsiveness and cross-browser compatibility in mind
• Ability to improvise, troubleshoot, and learn new skills on the job.
• Proficient understanding of code versioning tools, such as Git/SVN
• Excellent coding and debugging skills
• A passion and the ability to make beautiful, smooth, delightful web experiences
• A "Will Do" attitude

• A team of aces, from top-tier schools and startups, to work with
• A fast-paced, data-driven, and fun work environment
• A huge appetite for new, disruptive, creative, and implementable ideas
• An open work culture

• Competitive salary
• Great working environment, opportunity to work directly with the founders on very exciting real-life problems.
• Opportunity to grow really fast.
• Opportunity to hire a team & mentor them in the future.
• ESOPs

1. Shortlist
2. Intro call of 15min
3. Assignment
4. 1-2 Tech rounds
5. HR round
6. Offer rollout

Mastree's engineering team is working towards building a data science engine that enables students to learn in a way they understand the best. We believe in delivering learning experiences through engagement. The product is designed with countless embedded interactive information pieces to help the students imbibe the concepts better. At Mastree we take pride in being a part of the product that holds the potential to revolutionise the education process.

We are looking for folks who are passionate about creating interaction rich interfaces. Creative individuals who believe in the power of visuals.

Responsibilities:

• Creating visual elements that users see and interact within our web platform.
• This makes your role crucial for the success of the product.
• Working closely with the design, product management and development teams to create elegant, usable, responsive and interactive interfaces across multiple devices.
• Ensuring that the application is optimised both in terms of technology and in delivering the best educational content.
• Building web platform for our live tutoring platform
• Creating interactive learning activities for K12 students and work on our upcoming products

Requirements:

• You are an avid programmer
• You have great grasp of fundamentals of JavaScript and ES modules, new ECMASCRIPT concepts
• You have experience in ReactJS web app development
• You are an exceptional problem solver, with attention to details.

Brownie Points:

• Good HTML and CSS skills
• Experience in React-Native app development
• Ability to work in small teams and wear multiple hats

• You will be part of a growing high functional team, responsible for delivering various frontend products to the end-users. Simplifying complex workflow and make it easy for the end-users.
• The team designs and develops various products from - financial apps targeted to invoice users, data-heavy app oriented to operational and support teams, a productivity app for sales teams,
• SDK that will be integrated into third-party apps, etc.
• You will work with business, product, and backend teams to work on new features and products.
• You are expected to drive the products to maximize its business impact and customer delight.
• You are expected to stay on top of tech innovations in the Web development space, experiment them and make suitable suggestions to enhance tech stack. Research and propose software programs that are compatible with future technologies.

• Design and implement Single Page Applications (SPAs) using modern JavaScript frameworks
• Integrating data from various back-end services
• Develop a simple-to-use user interface for a complex product, apply new technologies, best design practices and usability patterns
• Contribute to end-to-end system architecture, working with/as cross-functional teams
• Collaborate with UX teams, product managers and other technical teams to create optimized and delightful user experiences
• Apply expertise of HTML5, bootstrap/foundation CSS frameworks
• Analyze the performance of layers in the frontend, backend and engineer designs/code to solve them
• Work with the product team to build flow and detail out the requirements
• Conversant with development for desktop and mobile browsers and hybrid apps.

• Proven working experience in web programming
• Top-notch programming skills and in-depth knowledge of modern HTML/CSS
• Solid understanding of how web applications work including security, session management, and best development practices
• Working with respectable size Single Page Application (SPA) project
• Expert in MVC like design patterns, modern JavaScript frameworks
• Hands-on experience with network diagnostics, network analytics tools
• Solid CS, OOP/OOD, design patterns
• Good grasp on usability and interaction design
• Track record in large-scale system software development
• Aggressive problem diagnosis and creative problem-solving skills
• Ability to work and thrive in a fast-paced environment, learn rapidly and master diverse web technologies and techniques

• Any framework - ReactJS, AngularJS, Backbone, Ember, VueJS
• DOM and Virtual DOM understanding
• API Integration. Understanding of session management. 

• Experience with server-side processing such as templating, packaging and delivery
• Some end-to-end system design experience, sensitive to security
• Experience working with webviews on Android and iOS
• Exposure to React Native
• Demonstrated visual design and layout skills
• Design and development of backend REST endpoint applications