Sr. Developer / Architect - Founded by ex Google ex Amazon engineers

Project Overview

We’re building Express AI, a SaaS platform that allows small and medium-sized businesses (SMBs) to easily train and deploy their own dedicated AI agents for customer service, technical support, sales, and more.

Our vision is to give SMBs the power of enterprise-grade AI without complexity. You’ll help build the core platform that powers this – including agent training interfaces, web deployment, dashboards, and integrations.

Key Responsibilities

• Develop scalable full-stack features using modern JavaScript frameworks

• Build and maintain AI agent training modules (upload docs, FAQs, tone settings)

• Integrate OpenAI, Whisper, LangChain, and other LLM APIs

• Implement user-facing dashboards for chat/voices/social/email agent monitoring

• Design multi-tenant systems with admin-level controls

• Ensure reliability and scalability of the platform as we grow

Tech Stack

• Frontend: React.js, Next.js, TypeScript

• Backend: Node.js, Express, MongoDB (or Postgres), Redis

• AI & NLP: OpenAI API (ChatGPT, Whisper), LangChain, Python (optional)

• DevOps: Docker, AWS or GCP (basic familiarity okay)

• Other: WebSockets for real-time chat, REST APIs, Git

Role Type

• Full Stack Developer (preferred)

• Frontend or Backend specialists also considered, but must be willing to collaborate on both sides

Experience Level

• 3 to 6 years of professional experience

• Previous work with SaaS platforms, AI tools, or multi-tenant architecture is a big plus

Must-Have Skills

• Proficiency in JavaScript/TypeScript

• Strong experience with React.js and Node.js

• Experience working with REST APIs and building secure web apps

• Solid understanding of cloud deployment (AWS/GCP/Firebase)

• Ability to work independently, self-manage, and deliver in a fast-paced environment

Nice-to-Have Skills

• Familiarity with LangChain, OpenAI, AI agent frameworks

• Experience with voice/chat integration

• Prior experience building tools for SMBs or customer support systems

Engagement Type

• Full-time (preferred) or part-time with clear weekly availability

• Remote (India-based candidates only)

Why Join Us?

• Work on a cutting-edge AI platform solving real problems for real businesses

• Fast-moving, no-red-tape team environment

• Build something that will impact millions of small businesses globally

Type - Work From Office

Requirements:

• Should have sound knowledge of PHP, MySQL, JQuery & javascript.
• Should know MVC framework Yii/Yii2
• Knowledge of mobile app APIs, JSON, etc.
• Knowledge of version control systems like GIT is a plus.
• Strong analytical and problem-solving skills.
• Troubleshoot and fix any issues relating to PHP programs.

Highlights:

• Working 5 days a week.
• Group Health Insurance for our employees.
• Work with a team of 200+ excellent engineers.
• Extra Compensation for Night Shifts.
• Additional Salary for an extra day spent in the office.
• Lunch buffets for all our employees.
• Yearly and quarterly awards with CASH amount, Dinner coupons, etc
• Team Dinners on Project Completion.
• Festival celebration, month end celebration and much more.

Job Description:

• Bachelor's or Master's degree in Computer Science.
• Proven experience in leading a team of backend engineers
• Strong organizational and project management skills.
• Proficiency with fundamental front end languages such as HTML, CSS and JavaScript.
• Familiarity with Android development - kotlin, RX-java, design pattern.
• Proficiency with server-side languages such as Spring boot, Hibernate.
• Familiarity with database technology such as MySQL and MongoDB.
• Familiarity with cloud platforms(GCP).
• Experience with Agile/Scrum methodologies
• Excellent verbal communication skills.
• Good problem-solving skills.
• Attention to detail.

Full Stack Developer Job Description:

1. Knowledge in MERN Stack is mandatory

2. Work with development teams and product managers to ideate software solutions

3. Design client-side and server-side architecture

4. Conduct Testing & Debugging, utilize script tools & write basic codes for design specifications

5. Build the front-end of applications through appealing visual design

6. Develop and manage well-functioning databases and applications

7. Write effective APIs

8. Troubleshoot, debug and upgrade software

9. Create security and data protection settings

10. Build features and applications with a mobile responsive design

11. Write technical documentation

12. Work with data scientists and analysts to improve software

We have an opening for Sr Lead Software Engineer -Full / Mern Stack Developer.

Responsibilities :

• Responsible for writing reusable, testable, and efficient code
• Design and implementation of low-latency, high-availability, and performant applications
• Implementation of security and data protection
• Understanding of performance testing and optimization techniques

Requirements

• Should have the ability to translate Wireframes and PSD Designs into functional web apps using HTML5, React , Node.js, and Mongo.
• Binding of UI elements to JavaScript object models
• Creating RESTful services with Node.js
• Architect scalable web architectures
• Must have proven experience in front ( Rect.js)& back-end development (Node.js)
• Work in a cross-functional team to deliver a complete user experience
• Must know MongoDB, Express, Node.js, & React., Typescript, CSS, HTML, Bootstrap
• Create Unit and Integration tests to ensure the quality of code
• Be responsive to change requests and feature requests
• Write code that is cross-platform and cross-device compatible
• Must have the ability to wear many hats and learn new technologies quickly
• Candidate must have good Knowledge of Node Debugging
• Understanding & proficiency in REST APIs.
• Should know Git Repository and Jira.
• Integration of data storage solutions [RDBMS, NoSQL DB]

Qualifications

Having Expereince in MongoDB - Document DataBase,

Node.js —Express(.js) web framework -Backend

React(.js) — a client-side JavaScript framework along with Bootstrap , HTML5, CSS3 - Frontend

Education : B Tech , BCA or Equivalent

Relevant Experience : 3 to 9 years : Full Stack developer

Preferred Candidate : Immediate Joiner

Location: Kolkata only ( Onsite).

CartX is a small, fast-growing, and remote-first company. We are a high converting one-page checkout and post-purchase one-click upsell for thriving eCommerce stores. We are looking for a Senior Software Engineer to join our mission and work on our ambitious product roadmap. Ideal candidates have a solid technical background on complex systems.

→ What you will be doing:
– Solve engineering problems that affects hundreds of customers
– Develop and launch end-to-end new key features
– Take ownership and responsibility of challenging tasks
– Interact and collaborate with the team
– Research, innovate and propose new ideas that can lead to new projects
– Play an important role by shaping our company’s best practices and culture
– Learn fast and adapt quickly

→ Required
– 5+ years of experience as a Software Engineer
– Experience on LAMP
– Experience on Bitbucket
– Knowledge on API’s such as Twilio, Stripe and others
– Great communications skills
– Fluent in English (written and speaking)

→ What We Offer
- Work remotely from home or any co-working space
- Work with a top-notch engineering team
- Unlimited vacation policy
- Ownership and autonomy over exciting tasks
-  Be part of an exciting fast-growing startup