Senior Full-Stack Developer- Next.js/TypeScript (SaaS Product)

Smyl Info Services; United States; Remote; USD 83,000 - 138,000; Part time

Job summary

Smyl Info Services seeks an expert full-stack engineer to design and deliver data-intensive web applications. You will implement core comparison logic, ingestion pipelines, and multi-tenant backend architecture with RBAC and secure authentication.

You’ll work with TypeScript, React, Next.js, and PostgreSQL, integrating LLMs and vector search while ensuring robust testing and smooth CI/CD deployments on Vercel.

Qualifications

• 5+ years of professional full-stack web application development in production environments.
• Deep mastery of TypeScript and React/Next.js.
• Typed domain modeling, state machines, and enforcing business rules with robust type systems.
• Proven ability to navigate, modernize, and enhance existing production codebases.
• Experience launching or contributing to deployed, user-facing web applications.

Responsibilities

• Feature Engineering: Design and build core comparison logic with source-level provenance.
• Data Processing Workflows: Develop document ingestion pipelines with page-level citation extraction and validation checks.
• Architecture & Multi-Tenancy: Implement backend with PostgreSQL, multi-tenant schemas, RBAC, and authentication.
• AI & Search Integration: Integrate LLM APIs and optimize vector search (Pinecone) for reliable outputs.
• System Quality & Delivery: Maintain automated tests (Vitest, Playwright), CI/CD (GitHub Actions), and deploy on Vercel.

Skills

TypeScript

React

Next.js

Data Modeling

AI Integration

Testing

CI/CD

Documentation

Tools

Next.js 15

PostgreSQL

Vitest

Playwright

GitHub Actions

Vercel

Job description

Engagement Details & Flexibility

• Role Type: Contract / Freelance / Part-Time or Full-Time


• Commitment: 20 to 40 hours/week (Open to candidates who can commit a minimum of 4 hours daily)


• Working Hours: Flexible working setup with a regular overlap during 9:00 AM 2:00 PM US Pacific Time (PT) for syncs and collaboration.


• Onboarding: Starts with a well-scoped paid trial project (approx. 10–15 hours) to establish collaborative alignment before transitioning into a long-term engagement.

Core Responsibilities

• Feature Engineering: Design and build core comparison logic that processes structured data against reference records to highlight key insights, variances, and gaps with source-level provenance.


• Data Processing Workflows: Develop document ingestion pipelines (PDFs, structured text) featuring page-level citation extraction and automated validation checks.


• Architecture & Multi-Tenancy: Implement robust backend architecture using PostgreSQL, incorporating multi-tenant isolation, structured version control, dynamic role-based access control (RBAC), and authentication.


• AI & Search Integration: Integrate LLM APIs for structured extraction and optimize vector search capabilities (Pinecone) to deliver accurate, reliable platform outputs.


• System Quality & Delivery: Maintain automated test suites (Vitest, Playwright), refine CI/CD pipelines (GitHub Actions), and ensure smooth release deployments on Vercel.

Technical Stack

• Frontend/Backend: Next.js 15 (App Router), React, TypeScript (strict mode)


• Database & Auth: PostgreSQL, Multi-tenant schemas, SSO/SAML/OIDC patterns


• Testing & Infrastructure: Vitest, Playwright, GitHub Actions CI, Vercel


• AI & Search: Pinecone vector index, LLM API integration

Candidate Profile & Qualifications

• Experience: 5+ years of professional full-stack web application development in production environments.


• Core Expertise: Deep mastery of TypeScript and React / Next.js.


• Domain Modeling: Hands-on experience with typed domain modeling, state machines, and enforcing business rules through robust type systems.


• Code Maintenance & Refactoring: Proven ability to navigate, modernize, and enhance existing production codebases.


• Track Record: Successfully launched or contributed significantly to deployed, user-facing web applications.


• Communication: Excellent written English skills with a self-directed, result-oriented approach to execution.