Lead Full Stack Developer

Fountane Archipelago  ·  Island Role

A Little Bit About the Role

We are looking for a Senior Product Engineer (L3) who thrives in complexity. Most engineers build on blank canvases — you build on someone else’s mess and leave it better than you found it.

The majority of your work at L3 will be on existing, live codebases — disorganised, partially documented, built by multiple teams over multiple years. Your job is to enter those systems, understand them before touching them, extend and clean them without breaking what works, and progressively bring them up to a standard where AI tooling can accelerate further development. This is the core of what L3 does at Fountane. If you have only built greenfield projects, this role will be hard.

You are expected to be genuinely full stack: comfortable owning web applications and mobile apps, the frontend, backend, database, state management, and API integration layer — without needing to hand off to a specialist.

You will work closely with the Concept Engineer on your Island — translating their prototypes into production architecture, raising technical blockers early, and keeping the sprint honest. You will also review code, mentor junior engineers, respond to production incidents, and contribute to the network’s shared knowledge base.

All of this is done primarily with Cursor and Claude as your execution and reasoning tools. AI-assisted engineering is not a feature of this role — it is the method.

AI-First Engineering Expectation

Cursor and Claude are your primary tools — not supplements. Engineers at L3 who are not using AI at the codebase level are not operating at this level.

At L3, AI-assisted engineering means:

• Loading full codebase context into Cursor before writing a single line — understanding the system before touching it.
• Writing scoped, precise refactor prompts that isolate changes to one concern at a time.
• Using Cursor to generate tests that document existing behaviour before any restructuring begins.
• Using Claude for architecture reasoning, decision documentation, and translating CE briefs into structured technical plans.
• Producing inline documentation and decision records as part of the AI-assisted workflow — not as an afterthought.
• Sharing effective prompt patterns and Cursor discoveries with the broader Fountane network — kept to yourself, they are a missed contribution.

Key Responsibilities

Legacy Codebase Refactoring & the Cleaning Phase

This is the primary L3 engagement type at Fountane. You will be handed existing, partially documented codebases — built by previous teams, often without tests, with inconsistent patterns — and your job is to refactor them into a clean, AI-promptable state without losing existing functionality. You use Cursor’s codebase context window to navigate safely, write characterisation tests before touching anything, and make changes in small, reviewable increments. The standard is: every module you leave should be easier to extend by AI tooling than when you found it.

Full Stack Development — Web & Mobile

Build and own the full application layer: React / Next.js web frontends, React Native or Flutter mobile apps, Node.js / Python backends, and relational and non-relational databases. You should be able to pick up web or mobile on any engagement without needing a handoff. Schema design, data modelling, and state architecture are yours to own — including diagnosing and fixing broken or leaking state in existing frontends.

Third-Party API Integrations

Integrate complex third-party services — payments (Stripe), communications (Twilio), auth (Auth0), and others — reliably and without creating brittle dependencies. Own the integration layer end to end: error handling, retries, failure modes, and documentation. If a third-party integration is flaky in production, that is your problem to own.

CE Collaboration & Sprint Integrity

Work directly with the Concept Engineer to translate prototypes into buildable technical plans. Review CE briefs before the sprint starts — if the scope is technically unrealistic, the time to say so is before work begins, not on demo day. Raise blockers against acceptance criteria proactively. You are the technical check on what the CE promises the client.

Security Awareness

Write code that does not require the Lead to security-audit every line. This means: input validation by default, no hardcoded secrets, correct auth scoping, safe handling of user data, and awareness of common vulnerabilities (injection, broken auth, insecure direct object references) in the context of the stacks you work in. You are not the security architect — the Lead owns that — but you are expected to produce code that does not introduce obvious vulnerabilities.

Production Incident Response

When something breaks in production, you are on it. Diagnose the issue, apply a safe fix or rollback, document what happened and why, and hand a clear summary to the Lead for the client post-mortem. Speed matters, but a bad fix that causes a second incident is worse than a slow fix that is correct. Response expectation: acknowledged within 1 hour, resolved or escalated with a clear status within 4 hours.

Codebase Navigation & Safe Refactoring

On all engagements — not just Cleaning Phase work — keep changes small, focused, and reviewable. One type of change per commit. Write tests that document existing behaviour before restructuring. Leave every module easier to understand than when you found it.

Code Review

Review pull requests from L1 and L2 engineers with specific, actionable feedback — not rubber-stamp approvals. A good code review at L3 leaves the author understanding what to do differently next time, not just what to fix now. Review weekly; do not let PRs age.

Mentoring

Review junior engineers’ code weekly with specific, useful feedback — this is distinct from quality-gate code review. The goal here is teaching, not gatekeeping. Run monthly pairing sessions to help them grow. The measure of good mentoring is whether they are becoming more capable and less dependent on you over time.

Documentation

Write short decision records when you make significant technical choices. Leave every module you touch easier to understand than when you found it. Treat documentation as part of the engineering work, not a separate task you do at the end.

Qualifications

• 5+ years of experience as a software engineer, with a strong track record on real production codebases you did not build from scratch — incomplete documentation, inconsistent patterns, other people’s decisions. If your experience is primarily greenfield, this role will be a difficult fit.
• Genuinely full stack across web and mobile: proficient in React / Next.js and at least one of React Native or Flutter, Node.js or Python on the backend, and comfortable with both relational and non-relational databases including schema design.
• Hands-on, daily Cursor and Claude usage at the codebase level. You should be able to describe concretely how you use AI in your engineering workflow — not in general terms.
• Experience integrating complex third-party APIs in production environments — not just following a quickstart guide. You should be able to describe an integration that failed in production and what you did about it.
• Solid security awareness for the stacks you work in: input validation, auth scoping, safe data handling. You do not need a security specialism, but you should not be writing code that introduces obvious vulnerabilities.
• Has conducted meaningful code reviews that improved the code and the author, not just approved the PR.
• Has coached or mentored junior engineers before, and done it well.
• Comfortable with production incident response — diagnosing issues under pressure, applying safe fixes, and communicating clearly to a Lead or client about what happened.
• Treats documentation as part of the job, not an afterthought.
• Bachelor’s or Master’s in Computer Science or a related field, or equivalent experience.

About Fountane

Fountane is a technology ventures lab - one part product studio, one part startup engine. We build high-quality software and AI products for clients ranging from fast-moving startups to large enterprises, and we co-build and invest in new companies when we see the right opportunity.

Founded in 2017 and headquartered in Minneapolis, we have grown to 60+ people across four continents and were recognised as one of America’s fastest-growing companies, ranking No. 699 on the Inc. 5000 with 595% three-year growth.

We are radically open-minded, serious about craft, and direct about expectations. If you want to do meaningful work without politics, this is the place.

Location: Mumbai or Remote

Duration: 3 to 6 months

About the Role

Websites.co.in is looking for a Full Stack Developer Intern to support our engineering team across backend and frontend development. You will work on real product features and fixes across our website builder platform used by small businesses globally. This role is designed for learners who want practical full stack exposure.

You will mainly assist, build small modules, fix bugs, and improve existing features under guidance.

What You Will Do

• Assist in building and updating features using basic PHP and Laravel
• Work on simple database queries and data handling
• Help create and modify REST API endpoints
• Build and improve basic responsive UI using HTML, CSS, and JavaScript
• Connect frontend pages with backend APIs using AJAX and JSON
• Fix minor bugs across frontend and backend code
• Support simple third party API integrations
• Use Git for basic version control tasks
• Learn and work with existing codebase and modules

Required Skills

• Basic knowledge of PHP and any MVC framework preferred
• Basic understanding of Laravel concepts is a plus
• Basic knowledge of HTML, CSS, and JavaScript
• Basic understanding of databases like MySQL
• Familiar with REST API basics
• Exposure to Git
• Has done at least one academic or personal web project
• Willingness to learn and take feedback

Perks

• Real product development exposure
• Mentored learning environment
• Fast skill growth
• PPO opportunity based on performance

Responsibilities

• Enhance and maintain our main web application, ASCLOGS, built on ASP.NET MVC

(.NET Framework 4.8) with features such as authentication, PDF generation via

IronPdf, audit logging with log4net, Twilio SMS integration, and data access through

PetaPoco.

• Support multiple companion projects including:

• CopyForm, an MVC tool that copies form templates between SQL Server

databases using AJAX and PetaPoco data access.

• SQLImportApp, a WinForms importer leveraging ExcelDataReader and

Z.Dapper.Plus for bulk inserts.

• DEAVerification, a WinForms app automating data retrieval via Selenium

WebDriver and storing results with PetaPoco.

• UniversalScrapperAPI, an ASP.NET Web API that scrapes licensing

information using Selenium and logs results with log4net.

• HL7DocAssistantSync, a VB.NET library for HL7 message processing and

PDF generation with PdfSharp.

• ChatGPT Implementation, a .NET 8 Web API example showing how we

integrate with OpenAI's ChatGPT service.

• S3MicroService, a .NET 8 Web API using AWS SDK packages

(AWSSDK.S3, AWSSDK.Extensions.NETCore.Setup) and Entity Framework

Core for storage.

• Maintain PowerShell utilities used for onboarding tasks such as document-to-PDF

conversion and CSV generation.

• Review existing code to improve reliability, enhance testability, and refactor large

code files (for example, BusinessLayer/BusinessLayer.cs is roughly 28k lines).

• Work closely with stakeholders to gather requirements for new features and ensure

compatibility with our SQL Server backend.

• Assist in modernizing legacy components and implementing best practices for

security, error handling, logging, and deployment automation.

Required Skills

• 10+ years of development experience

• Extensive experience with C# and the .NET ecosystem, including both legacy .NET

Framework and modern .NET Core / .NET 8.

• Solid understanding of ASP.NET MVC, Web API, and Windows Forms development.

• Familiarity with PetaPoco, Entity Framework Core, and SQL Server.

• Experience integrating third-party services such as Twilio, OpenAI, Selenium

WebDriver.

• Ability to write and troubleshoot PowerShell scripts for automation tasks.

• Comfortable navigating large codebases and improving code quality through

refactoring, unit testing, and documentation.

• Proficiency with version control (Git) and the Visual Studio toolchain.

Preferred Skills

• Background in healthcare or regulated industries, since many applications manage

sensitive data (e.g., DEA verification, HL7 messaging).

• Knowledge of PDF generation libraries (IronPdf, PdfSharp) and logging frameworks

(log4net).

• Experience with CI/CD pipelines for .NET applications.

• Nice to have Unit Testing frameworks (i.e. NUnit, MS Testing Framework )

Location & Work Environment

This role requires working with Visual Studio on Windows for the .NET Framework solutions

and .NET 8 projects. Experience with IIS or IIS Express is helpful for local development and

testing.

Job Description: Principal Engineer (Full Stack Architect)

Job Title: Full Stack Architect

Location: Hyderabad, India

Experience: 15Years to 20 years (4+ years in Enterprise Architecture)

Technology Stack: MERN (MongoDB, Express, React, Node.js), Distributed Systems, Cloud (GCP/Azure), Neo4j, Vector Databases, SQL and NoSQL Databases, Knowledge Graphs.

Industry: Enterprise Software, Large-Scale Distributed Systems, Machine Learning

Job Summary

As a Full Stack Architect, you will play a pivotal role in designing and architecting large-scale distributed systems with a strong focus on the MERN stack (MongoDB, Express.js, React, Node.js). You will lead the design and implementation of enterprise-grade software solutions that leverage cloud infrastructure (GCP/Azure), knowledge graphs (Neo4j), vector databases, and machine learning at scale. In this role, you will work closely with cross-functional teams including data scientists, cloud engineers, and front-end developers to deliver high-performance, secure, and scalable applications.

This role requires a deep understanding of distributed systems architecture, graph databases, machine learning systems, and cloud computing, with a strong focus on building solutions that meet business and technical needs. The ideal candidate will have 12+ years of experience with a proven track record of architecting full-stack systems and leading engineering teams in a fast-paced, innovative environment.

Roles and Responsibilities

Full Stack Architecture: Design, develop, and maintain highly scalable, distributed, and fault-tolerant enterprise applications using the MERN stack (MongoDB, Express.js,

React, Node.js).

Distributed Systems: Architect and design large-scale distributed systems that handle high- volume, low-latency data processing.

Cloud Engineering: Implement and maintain cloud infrastructure solutions on GCP or AWS,ensuring high availability, scalability, and performance.

Knowledge Graphs and Databases: Design and optimize complex data models using Neo4j, vector databases, and other NoSQL solutions to manage interconnected data efficiently.

Enterprise Solutions: Architect and deliver cloud-native enterprise software solutions that meet enterprise-grade security, compliance, and performance requirements.

Data Structure & Algorithms (DSA): Lead by example in writing efficient, high-performance code and optimize software with a strong focus on algorithms, data structures, and system design principles.

Collaboration: Work with engineering, data science, and product teams to translate business requirements into scalable technical solutions.

Mentorship: Mentor junior engineers and foster a collaborative team environment.

Performance Optimization: Ensure system performance, scalability, and reliability throughcode reviews, optimizations, and best engineering practices.

Documentation & Best Practices: Maintain comprehensive architecture documentation and promote engineering best practices across teams.

Mandatory Requirements

Experience: 12+ years of full-stack development experience, with significant expertise

in building and architecting applications using the MERN stack (MongoDB, Express.js,

React, Node.js).

 Distributed Systems: Proven track record of architecting and implementing large-scale

distributed systems with a focus on reliability, scalability, and performance.

 Cloud Expertise: Extensive hands-on experience with cloud infrastructure (GCP or AWS),

with a deep understanding of cloud services such as compute, storage, networking, and

security.

 Database Systems: Expertise in NoSQL databases like MongoDB and graph databases like

Neo4j. Experience with vector databases for high-dimensional data processing.

 Knowledge Graphs: Hands-on experience in designing and working with knowledge graphs

for solving complex data relationships.

 Data Structures & Algorithms: Strong knowledge of DSA with practical experience in

solving complex technical challenges.

 Microservices Architecture: Experience in designing and developing microservices-based

architectures and ensuring high availability.

 DevOps ; Automation: Knowledge of DevOps practices (CI/CD), containerization (Docker), and orchestration (Kubernetes).

 Agile Methodologies: Experience with Agile development methodologies, including SCRUM, TDD, and iterative development.

Nice-to-Have Requirements

 Front-End Expertise: Advanced experience with React.js, with knowledge of modern front- end technologies (Next.js, Redux, TypeScript).

 Cloud Certifications: Google Cloud Professional Architect or Azure Certified Solutions Architect certifications.

 Data Engineering: Hands-on experience with data pipelines, ETL processes, and big data technologies (e.g., Apache Spark, Kafka).

 AI/ML Ops: Experience in deploying machine learning models using MLOps frameworks and automating ML pipelines.

 Graph Analytics: Experience in graph algorithms and analytics, with the ability to model and query complex relationships in a graph database.

 System Design: Experience in conducting system design reviews, providing insights into performance bottlenecks, scalability, and trade-offs.

 Security & Compliance: Knowledge of enterprise-level security protocols and data privacy compliance frameworks (e.g., SOC2, GDPR).

Leadership: Proven experience in leading cross-functional teams, setting technical roadmaps, and ensuring alignment between business and technical goals.

MERN Stack Developer

2.5+ YEARS

Roles and Responsibility

Working experience as a MERN Stack Developer.

Design, code and manage large scale services using cutting edge technologies (NodeJs, ReactJS/AngularJS/VueJs etc).

In-depth knowledge of NodeJS.

Creating secure RESTful-based web services in XML or JSON.

Good knowledge in ECMAScript(6/7/8) is essential.

Strong fundamentals in Data Structures and Algorithms.

Experience implementing applications using Angular or React.

Should have an working experience with state management, React Hooks, React Fragments etc.

Should have a good Knowledge of Redux, Flux, and Webpack.

Writing the test case for components.

Experience working with Docker, Redis, MySQL, MongoDB.

Comfortable taking challenges and learning new technologies.

Excellent communication skills and client-facing experience.

Ability to mentor and build the team.

Knowledge of code versioning tools such as Git, Bitbucket or SVN.

Knowledge of the following will be considered as an advantage

Experience with Socket.IO for Real time communications.

Consumer Web Development Experience for High-Traffic, Public Facing web applications.

Caching with Redis For Speedy Performance.

Experience with cloud message APIs.

Knowledge of GraphQL, PostgreSQL.

Knowledge of NextJs.

Knowledge of any frameworks of NodeJS.

Experience with Progressive Web applications.

Knowledge of SSR.