About the role

Role Overview

We’re seeking a Full Stack Software Engineer to lead and own critical marketplace features end-to-end—from design through deployment. You’ll help scale the platform’s backend (order matching, transactions, payments, and data integrity) and refine the frontend user experience (TypeScript + Next.js), while also building internal operational tools.

Responsibilities

Own and lead development of key features and subsystems from design to deployment
Make technical decisions and set priorities to deliver quickly without sacrificing quality
Build, maintain, and scale the marketplace backend with an emphasis on:
- Order matching
- Transaction flows
- Payments
- Reconciliation
- Concurrency, correctness, and speed
Ensure data integrity, auditability, and resilience across systems
Translate UX/UI designs into high-performance, accessible frontend components using TypeScript and Next.js
Optimize frontend performance using SSR, code splitting, and lazy loading
Work closely with PostgreSQL on data modeling, query optimization, and schema design
Develop and enhance internal tools (accounting, logistics, fraud detection, operational dashboards)
Mentor junior developers, perform code reviews, and promote best practices
Improve technical architecture, testing strategies, and observability
Participate in incident management and troubleshooting to maintain reliability

Requirements

3+ years of full-stack engineering experience (startup or fast-paced environments preferred)
Strong proficiency in TypeScript and Next.js
Solid backend experience with Node.js (or similar)
Hands-on PostgreSQL experience (data modeling, query optimization, schema design)
Experience building scalable backend services and monitoring/observability tools
Ability to build internal tools for operational efficiency
Strong problem-solving skills with pragmatic trade-off decisions
Good communication skills to translate business needs into technical solutions
Ability to work independently and lead projects or small teams

Nice-to-Haves (implied)

Experience with incident response and production troubleshooting
Familiarity with auditability and resilient system design for financial/trading workflows

About Sundayy

Sundayy (Pure) is building a modern, transparent marketplace for rare coin and precious metal trading. The company focuses on trust and clarity through an order-book based platform, combining traditional trading reliability with cutting-edge technology to improve speed, transparency, and security.