Responsibilities:
- Write effective, scalable code
- Develop Connectors tool GUI for various source and target systems/platform/products
- Test, debug, build and deploy UI components in the existing product
- Improve functionality of existing SDK/Frameworks
- JavaScript
- ReactJS
- Redux-Saga
- ES6 (or TypeScript) syntax
- Good problem-solving
- Good debugging
Good to Have:
- TypeScript experience
- Material UI experience
- JEST knowledge
- Git and Github/Gitlab/Bitbucket experience

About Semperfi Services and Solutions
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We are seeking a highly skilled React JS Developer with exceptional DOM manipulation expertise and real-time data handling experience to join our team. You'll be building and optimizing high-performance user interfaces for stock market trading applications where milliseconds matter and data flows continuously.
The ideal candidate thrives in fast-paced environments, understands the intricacies of browser performance, and has hands-on experience with WebSockets and real-time data streaming architectures.
Key Responsibilities
Core Development
- Advanced DOM Operations: Implement complex, performance-optimized DOM manipulations for real-time trading interfaces
- Real-time Data Management: Build robust WebSocket connections and handle high-frequency data streams with minimal latency
- Performance Engineering: Create lightning-fast, scalable front-end applications that process thousands of market updates per second
- Custom Component Architecture: Design and build reusable, high-performance React components optimized for trading workflows
Collaboration & Integration
- Work closely with traders, quants, and backend developers to translate complex trading requirements into intuitive interfaces
- Collaborate with UX/UI designers and product managers to create responsive, trader-focused experiences
- Integrate with real-time market data APIs and trading execution systems
Technical Excellence
- Implement sophisticated data visualizations and interactive charts using libraries like Chartjs, TradingView, or custom D3.js solutions
- Ensure cross-browser compatibility and responsiveness across multiple devices and screen sizes
- Debug and resolve complex performance issues, particularly in real-time data processing and rendering
- Maintain high-quality code through reviews, testing, and comprehensive documentation
Required Skills & Experience
React & JavaScript Mastery
- 5+ years of professional React.js development with deep understanding of React internals, hooks, and advanced patterns
- Expert-level JavaScript (ES6+) with strong proficiency in asynchronous programming, closures, and memory management
- Advanced HTML5 & CSS3 skills with focus on performance and cross-browser compatibility
Real-time & Performance Expertise
- Proven experience with WebSockets and real-time data streaming protocols
- Strong DOM manipulation skills - direct DOM access, virtual scrolling, efficient updates, and performance optimization
- RESTful API integration with experience in handling high-frequency data feeds
- Browser performance optimization - understanding of rendering pipeline, memory management, and profiling tools
Development Tools & Practices
- Proficiency with modern build tools: Webpack, Babel, Vite, or similar
- Experience with Git version control and collaborative development workflows
- Agile/Scrum development environment experience
- Understanding of testing frameworks (Jest, React Testing Library)
Financial Data Visualization
- Experience with financial charting libraries: Chartjs, TradingView, D3.js, or custom visualization solutions
- Understanding of market data structures, order books, and trading terminology
- Knowledge of data streaming optimization techniques for financial applications
Nice-to-Have Skills
Domain Expertise
- Prior experience in stock market, trading, or financial services - understanding of trading workflows, order management, risk systems
- Algorithmic trading knowledge or exposure to quantitative trading systems
- Financial market understanding - equities, derivatives, commodities
Technical Plus Points
- Backend development experience with GoLang, Python, or Node.js
- Database knowledge: SQL, NoSQL, time-series databases (InfluxDB, TimescaleDB)
- Cloud platform experience: AWS, Azure, GCP for deploying scalable applications
- Message queue systems: Redis, RabbitMQ, Kafka, NATS for real-time data processing
- Microservices architecture understanding and API design principles
Advanced Skills
- Service Worker implementation for offline-first applications
- Progressive Web App (PWA) development
- Mobile-first responsive design expertise
Qualifications
- Bachelor's degree in Computer Science, Engineering, or related field (or equivalent professional experience)
- 5+ years of professional React.js development with demonstrable experience in performance-critical applications
- Portfolio or examples of complex real-time applications you've built
- Financial services experience strongly preferred
Why You'll Love Working Here
We're a team that hustles—plain and simple. But we also believe life outside work matters. No cubicles, no suits—just great people doing great work in a space built for comfort and creativity.
What We Offer
💰 Competitive salary – Get paid what you're worth
🌴 Generous paid time off – Recharge and come back sharper
🌍 Work with the best – Collaborate with top-tier global talent
✈️ Adventure together – Annual offsites (mostly outside India) and regular team outings
🎯 Performance rewards – Multiple bonuses for those who go above and beyond
🏥 Health covered – Comprehensive insurance so you're always protected
⚡ Fun, not just work – On-site sports, games, and a lively workspace
🧠 Learn and lead – Regular knowledge-sharing sessions led by your peers
📚 Annual Education Stipend – Take any external course, bootcamp, or certification that makes you better at your craft
🏋️ Stay fit – Gym memberships with equal employer contribution to keep you at your best
🚚 Relocation support – Smooth move? We've got your back
🏆 Friendly competition – Work challenges and extracurricular contests to keep things exciting
We work hard, play hard, and grow together. Join us.
About Credilio
Founded by a bunch of serial entrepreneurs having fintech and banking experience, Credilio is building the next generation tech-enabled marketplace for financial products. While English-speaking literate India is adequately served by the banks, our focus is on the Bharat - i.e. the next 200 million middle and lower-middle-class Indians who are expected to fuel the demand for financial products.
We are looking for smart Full Stack Javascript Engineers who want to make a difference in the way people consume financial services in India.
Responsibilities
- Build reusable code and libraries for future use.
- Own & build new modules/features end-to-end independently.
- Collaborate with other team members and stakeholders.
- Work in an agile environment to rapidly build high quality and robust features.
- Proactively discover, evaluate, and implement new technologies to improve development efficiency.
Required Skills
- Master in Vue.js (Nuxt.js) and HTML/CSS.
- Hands-on with TypeScript will be a big plus.
- Hands-on with Tailwindcss will be a plus.
- Experience with modern JS toolchains such as Webpack, Grunt, Bower, and Yeoman.
- Understanding the nature of asynchronous programming and its quirks and workarounds.
- Open Source enthusiast.
- Comfortable with Test Driven Development.
- Can learn and adapt fast, as well as identifying and solving problems.
- Understanding of Git, SPA, PWA, Docker.
Job Perks
- Get to work with a highly passionate team of engineers.
- Open and embracing culture towards the latest hot technologies.
- A high level of freedom & responsibility.
About Optiblack LLC
Optiblack LLC is a company that specializes in providing tech and analytics services. We offer a range of solutions to help businesses meet their goals, including:
- Data Analytics: we can help you extract insights from your data to make informed decisions.
- Web Development: we can design and build custom websites for your business.
- Mobile App Development: we can create mobile apps for both iOS and Android platforms.
- AI and Machine Learning: we can leverage these technologies to automate tasks and improve efficiency.
Optiblack LLC has a team of experienced professionals who can help you with your project. They have a track record of success in delivering high-quality solutions to our clients.
About the Role
We are looking for a passionate and talented intern developer to join our growing team at Optiblack LLC. This is a fantastic opportunity to gain hands-on experience building and maintaining our React Native mobile application. You will work alongside experienced developers and contribute to a product used by millions of users.
Responsibilities:
- Develop new features and functionalities for our React Native mobile application.
- Collaborate with designers and backend developers to ensure a seamless user experience.
- Write clean, maintainable, and well-documented code.
- Fix bugs and identify areas for improvement in the existing codebase.
- Stay up-to-date with the latest trends and technologies in React Native development.
- Participate in code reviews and provide constructive feedback.
Qualifications:
- Strong understanding of React Native development concepts.
- Experience with JavaScript (ES6+) and related frameworks.
- Familiarity with React development principles is a plus.
- Experience with Git version control system.
- Excellent problem-solving and debugging skills.
- Ability to work independently and as part of a team.
- Strong communication and interpersonal skills.
- A passion for learning and staying updated with the latest technologies.
Bonus Points:
- Experience with building cross-platform mobile applications.
- Experience with UI/UX design principles.
- Experience with unit testing frameworks like Jest or Mocha.
- Experience working on Social Media Apps or having an interest in working on them.
** Internship Duration:** 3 Months
Location: Remote
To Apply:
Please submit your resume and a cover letter explaining your interest in the position and why you think you would be a good fit for our team
- Designing and developing user interfaces using angular best practices.
- Adapting interface for modern internet applications using the latest front-end technologies.
- Writing JavaScript, CSS, and HTML.
- Developing product analysis tasks.
- Making complex technical and design decisions for Angular projects-
We are looking for a great JavaScript developer who is proficient with React.js. Your primary focus will be on developing user interface components and implementing them following well-known React.js workflows (Redux). You will ensure that these components and the overall application are robust and easy to maintain. You will coordinate with the rest of the team working on different layers of the infrastructure. Therefore, a commitment to collaborative problem-solving, sophisticated design and quality products is important.
Responsibilities
- Developing new user-facing features using React.js
- Building reusable components and front-end libraries for future use
- Translating designs and wireframes into high quality code
- Optimizing components for maximum performance across a vast array of web-capable devices and browsers
Skills
- Strong proficiency in JavaScript, including DOM manipulation and the JavaScript object model
- Thorough understanding of React.js and its core principles
- Experience with popular React.js workflows (Redux)
- Familiarity with newer specifications of EcmaScript
- Experience with data structure libraries (e.g., Immutable.js)
- Knowledge of isomorphic React is a plus
- Familiarity with RESTful APIs
- Knowledge of modern authorization mechanisms, such as JSON Web Token
- Familiarity with modern front-end build pipelines and tools
- Experience with common front-end development tools such as Babel, Webpack, NPM, etc.
- Ability to understand business requirements and translate them into technical requirements
- A knack for benchmarking and optimization
- Familiarity with code versioning tools GIT
- Familiarity with Docker
Requirements:
- Bachelor’s/Master in computer science
- 3-5 years of work experience
- Excellent problem-solving skills
- Able to work in a fast, unstructured environment
- Excellent communication and collaboration skills
- Must have access to FTTH internet connection
- Delivering a complete Front-end application
- Ensuring high performance on mobile and desktop
- Writing tested, idiomatic, and documented JavaScript, HTML and CSS
- Coordinating the workflow between the graphic designer, the HTML coder, and yourself
- Cooperating with the back-end developer in the process of building the web service/ application
- Communicating with external web services
Technical/Functional Skills:
- 3 to 5 yrs of experience working as an Angular Developer
- Experience in Angular 7,8,9 versions are mandated.
- Proficiency in CSS, HTML, javascript
- Experience on Multi-Language is preferable
- Knowledge on Arabic design is a plus
- Experience on Components based Architecture
- Experience on CSS Grids and Flex Layout mandatory
- Well versed with coding standards
- Be able to provide effort estimations based on the customer requirements
- Experience of implementing enterprise level Angular applications and the related Architecture
- Implementation knowledge on Agile, working experience on Continuous Integration (CI) process is required
- Experience of integration with SAP is highly desirable
- Working knowledge with databases ORACLE, SQL Server, mySQL
- Be hands-on technical and should work as either individual contributor or team member
- Must have knowledge in code version mechanism using tools like TeamCity, GitHub
- Knowledge on Agile scrum and waterfall methodology
- Optimizing performance of code and reviewing code of junior developers
- Work closely with the architecture team and provide architecture inputs
- Experience with understanding of mobile related frameworks like Cordova is a plus
- Comfortable dealing with APIs and utilizing oDATA/REST / JSON interfaces
- End-to-End experience - Discovery to Deployment of Angular applications Soft Skills Required
- Good communication and interpersonal skills
- Candidates should be independent thinkers, thought leaders, good presentation and communication skills and great at solving problems
- Minimum 10 years of relevant work experience in similar roles.
- JavaScript and HTML/CSS UI development experience with React and Redux.
- Solid experience with displaying charts, reports and graph data structures.
- Solid experience using REST APIs and GraphQL
- Comfortable with building UIs from mockups.
- Outstanding collaboration and communication skills. Ability to effectively collaborate with distributed team.
- Understand and practice agile development methodology.
- Prior experience working in a software product company.
Myntra’s Engineering team builds the technology platform that empowers our customers’ shopping experience and enables the smooth flow of products from suppliers to our customers’ doorsteps. We work on areas such as building massive-scale web-applications, engaging user-interfaces, big-data analytics, mobile apps, workflow systems, inventory management etc. We are a small technology team where each individual makes a huge impact. You will have the opportunity to be part of a rapidly growing organization and gain exposure to all the parts of a comprehensive eCommerce platform.
You will be a part of: Supply Chain Management (SCM)
Myntra-Jabong Supply Chain Management systems form the backbone of our core business and customer experience. Any business runs on a simple construct of Demand (Consumer) and Supply (Producer). However, a set of complex and intricate methods, processes and systems connect the demand with supply in a deterministic and predictable way. These methods, processes and systems collectively form the Supply Chain for the business. The multi-billion-dollar Myntra-Jabong business fundamentally rests on a set of highly scalable, robust and intelligent Supply Chain Management systems that solve real-world problems of predicting the demand from millions of our customers, for a combination of millions of products from our product catalogue, and intelligently connecting that demand to thousands of national and international sellers or suppliers using a set of advanced homegrown tech products that we build and manage.
SCM engineering employs new-age technologies such as Distributed Computing constructs, Machine Learning, Deep Learning, Computer Vision, Artificial Intelligence; scalable data stores in Mongo, Redis, Cassandra, MySQL, Elastic Search, Solr; scalable programming constructs in Node.js, GoLang, Java; JavaScript, Python, and new-age frameworks such as ReactJS and ReactNative to solve some of the hardest problems in the e-commerce business
with world-class software products.
The SCM engineering at Myntra-Jabong operates within two distinct verticals: Supply-chain Outbound (Fulfilment systems) & Supply-chain Inbound (Selection systems, Partner experience).
Responsibilities
● Technical Guidance: You will provide technical leadership to a team of excellent software engineers; this
requires that you have the technical depth to make complex design decisions and the hands-on ability to
lead by example.
● Execution and Delivery: You will be expected to instil and follow good software development practices
and ensure timely delivery of high-quality products. You should be familiar with agile practices as well as
be able to adapt these to the needs of the business, with a constant focus on product quality.
● Team management: You will be responsible for hiring and mentoring your team; helping individuals
grow in their careers, having a constant dialogue about their aspirations and sharing prompt, clear and
actionable feedback about performance.
Skills / Experience
● Total of 9+ years’ in developing front-end for large scale web based consumer facing products and 2 + years’ experience in team management
● Degree in Computer Science or related field.
● Good understanding of mobile platforms and browsers.
● Strong CS & HTTP fundamentals.
● Experience and expertise in UI architecture, component/framework design.
● In depth strength and experience in JavaScript.
● Excellent programming skills in HTML5, CSS3.
● Building advanced responsive layouts.
● Node.js background is essential, React.js is a plus.
● Ability to write code compatible across browsers and other clients.
● Exposure to mobile-based interfaces, social media.
● Good understanding of backend systems i.e. web services, APIs from consumer
perspective.
Requirements
● Technical depth
o Strong technical competence required to gain credibility. Ability to architect, design and code
yourself. Technical experience in building and operating web-based applications. Deep
understanding of all layers of the web-stack work (from the client interface to the database).
Knowledge of multiple technology stacks/languages/tools and their pros/cons.
● Execution ability
o Focus on delivering products in a timely manner with high quality. Familiarity with multiple software
development practices and tools, and the proven ability to adapt, champion and institute good
practices and tools.
● Strong understanding of object- oriented programming, concurrency and fundamentals of
computer-science.











