We are a B2B SaaS startup building a data-centric enterprise platform for corporate treasury and investor relations teams.

Our MVP has been completed by an external development agency. We are now planning a structured transition to a senior, hands-on full-stack engineer who will take over post-MVP, ensure continuity, improve quality, and help shape the product’s next phase. This is not a greenfield build and not a “move fast and break things” role. The focus is quality, security, maintainability, and thoughtful iteration. We are looking for a long-term partner (initially contract, with potential to extend significantly).

Responsibilities
Take over day-to-day ownership of an existing production SaaS codebase
Work with the founder and fractional technical architect to:
review architecture decisions
stabilise and harden the platform
gradually improve code quality and test coverage
Deliver incremental product features and UX improvements

Ensure strong standards around:
security
access control
data integrity
auditability

Support early enterprise pilots and feedback-driven iteration

Collaborate with external vendors where needed (design, infra, audits)

Current Tech Stack
Backend
Node.js / TypeScript
NestJS (modular, service-oriented architecture)
PostgreSQL
REST APIs
Role-based access control (RBAC)

Frontend
React
TypeScript

Modern component-based UI (design system already defined)

Infrastructure / DevOps
Cloud-hosted (GCP)
Docker
CI/CD pipelines
Environment separation (dev / staging / prod)

Other

Multi-tenant SaaS architecture
Enterprise security mindset (GDPR, data isolation, logging)
No heavy AI/ML today (future roadmap item)
Ideal Profile

You are someone who:
Has 5–10+ years of professional experience
Has taken at least one SaaS product from MVP → production → real users
Is comfortable inheriting and improving an existing codebase
Thinks in terms of systems, not just features
Communicates clearly with non-technical founders
Is pragmatic, structured, and calm under ambiguity

This role is not suitable if you:
Prefer greenfield projects only
Dislike working with existing architectural constraints
Want a purely short-term gig

Engagement Details
Contract via Upwork
Initial scope: 6+ months
Expected workload: 15–30 hours/week
Strong likelihood of extension

Competitive hourly rate for senior talent

Application Instructions (Important)

Please include:
A short summary of similar SaaS products you’ve worked on
An example where you took over an existing codebase
Your experience with NestJS + React
Your preferred hourly rate and weekly availability