Full-Stack Developer (Node.js + React) [Senior-Level]

🌐 Welcome!
You’re about to apply for the Full-Stack Developer (Node.js + React) role.
Remote · Senior-Level · Weekly Pay

AI SaaS Platforms (Multi-ESP, High-Scale Email Systems)

🔧 About the Role

We’re looking for a highly skilled Full-Stack Developer with a strong track record in building production-ready SaaS platforms, ideally with experience in high-volume email, multi-ESP rotation, and campaign automation.

You’ll own features end-to-end, from backend services and scheduling engines to dynamic React dashboards. You’ll help design and maintain multi-tenant systems supporting thousands of users, unlimited mailbox connections, and large-scale, high-frequency email workflows.

You should be comfortable building for scale, architecting resilient systems, and solving deliverability challenges across multiple mailbox providers (Gmail, Outlook, Yahoo, custom SMTP/IMAP). You can work independently and thrive in a fast-paced, async environment.

🛠️ Responsibilities

Develop and maintain full-stack features using Node.js and React (or Next.js)
Build and manage email sending engines (IMAP/SMTP, CRON jobs, inbox rotation, throttling)
Integrate third-party APIs including Gmail API, Outlook/Office 365 API, Stripe, OpenAI, and others
Implement and maintain user authentication (OAuth2, app passwords) and role-based access
Architect robust mailbox rotation and quota management logic for unlimited inboxes per user
Create and optimize RESTful or GraphQL APIs for frontend consumption
Design responsive, performant dashboard UI and campaign builders
Work with GitHub for source control and follow CI/CD processes
Collaborate asynchronously, communicate clearly, and deliver reliable progress updates

🧰 Tech Stack

Frontend: React / Next.js, Tailwind (or any modern CSS)
Backend: Node.js (Express, or similar)
Database: PostgreSQL / MongoDB / Firebase (flexible)
Infrastructure: GitHub + CI/CD + AWS via CodeSmash (Lightsail or EC2)
Integrations: Gmail API, Outlook/Office 365, Yahoo, OpenAI, ElevenLabs, SMTP, IMAP, Stripe
Bonus: Redis, job queues (BullMQ, SQS), background workers, cron jobs, Webhooks, email parsing

✅ Requirements

3+ years experience as a full-stack developer
Strong proficiency in Node.js, JavaScript, and React
Experience integrating with multiple mailbox providers (Gmail, Outlook, Yahoo, SMTP, etc.)
Solid understanding of API integration, background job queues, and backend workflows
Familiarity with email protocols (SMTP, IMAP), inbox rotation, and deliverability best practices
Experience building admin dashboards or analytics views
Comfortable working with third-party services (e.g., Stripe, OpenAI, Gmail, Outlook)
Familiarity with Git-based workflows and cloud deployment (AWS preferred)
Able to write secure, modular, and maintainable code
Reliable communication and ability to work independently

⭐ Preferred

Experience architecting high-scale SaaS platforms (multi-tenant, millions of emails/month)
Familiar with deployment on AWS (Lightsail/EC2) or similar platforms
Exposure to cold email, marketing automation, CRM, or mass email delivery tools
Experience working in remote, async environments

TL;DR:

Full-stack dev for scalable SaaS (Node.js + React)
Remote, async, India-preferred
Work on real features (email engines, inbox rotation, billing, dashboards)
Must know: multi-ESP, quotas, rotation, OAuth, APIs, GitHub
Monthly retainer, long-term possible
Send code samples, rate, and availability to apply

📋 Please enter your Name and Email to get started.

Once you click Start Now, you’ll begin your async interview—a mix of short form-fields and media tasks to help us vet your technical chops.

🚨 Before You Begin

✅ Make sure your camera, microphone, and screen-recording tool are working

💻 Use a laptop or desktop—mobile devices are NOT recommended

🌐 Ensure a stable internet connection

🎯 Be authentic and clear—we value accuracy over polish

⚠️ Double-check your setup—once you start, you can’t go back

🎬 Ready?

Fill in your details and click Start Now. If you’re a strong fit, we’ll invite you to a live interview.

We’re excited to see how you work!

Complete your application

First name

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Last name

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Your email

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Answer these questions to complete the application:

What is your typical internet speed? (Mbps)
How many hours per week are you available to work?
When are you available to start?
Do you have any daily responsibilities (e.g., childcare) that may affect your schedule?
Are you comfortable working 3–4 hours overlapping with USA daytime?
Do you currently work any other jobs or contracts or school?
Which mailbox/email service providers have you integrated or automated sending for in a real project? (Select all that apply)
How many emails can typically be sent from 1 Gmail or SMTP per day without issues? (Please give typical sending limits for Gmail, Outlook, and generic SMTP based on your experience.)
Which tool/library would you use in Node.js to send SMTP emails at scale? (List all tools/libraries you would use for scalable, production sending.)
Do you agree that any work submitted is original and you’re comfortable working under NDA and IP assignment?
Have you ever built or worked on a cold email platform before?
Tell us about yourself.
Walk us through a full-stack project you’ve built solo, from idea to launch. What tech did you use, what challenges did you overcome, and what was your favorite part?
If a warm-up or bulk email campaign fails in production (e.g., major drop in open rate, or hundreds of SMTP bounces), how would you debug and solve the problem?
Walk us through how you’d build an email warm-up engine in Node.js
How would you dynamically personalize ({{firstName}}, {{company}}, etc.) in high-volume campaigns?
What tools do you use for backend, frontend, deployment, logging, error handling, and scaling?
How would you build a system with robust inbox or SMTP rotation? How would it work?
If an SMTP fails during a campaign, how should the system retry and log errors?
How have you built a campaign builder or complex form UI at scale? What tech did you use?
How would you deploy, monitor, and scale a cold email platform used by 30,00+ customers and thousands of mailboxes?
What is your experience integrating OAuth2 for Gmail/Google Workspace or Microsoft Outlook/Office 365? How would you securely manage tokens for thousands of connected mailboxes?
What’s the hardest scaling or deliverability problem you’ve solved in production SaaS? How did you fix it?

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