Senior Fullstack Engineer

Description

Crossian is a high-growth technology-driven e-commerce business. As a start-up formed in 2020, we have created a fast-paced and dynamic environment, enabling our people to reach a cumulative average growth rate of over 1000% in the last 5 years.

We're forming an elite Fullstack squad that operates differently, working with AI-driven products. No "that's not my ticket" culture. Each engineer owns a feature end-to-end - from data model to UI pixel - and thinks like a Product Owner when scoping, like a Solutions Architect when designing, and like a craftsman when coding. 

If you want to work with people like that and become like them, this is the next step.

What you'll do

Feature ownership

• Take a feature from kick-off to production: data model, API design, service layer, UI.
• Own reliability, performance, and observability of what you ship - not just the happy path.
• Turn product goals into concrete technical specs.

System design & architecture

• Design full-stack architectures: databases, APIs, queues, caches, frontend rendering strategies.
• Apply patterns (Clean Architecture, Event - Driven, etc) where they fit the problem.
• Write design docs and lead technical discussions.

Backend

• Build well-tested APIs and microservices in Node.js, Go, or Python - whichever fits.
• Design and optimize relational and non-relational databases.
• Work with event streaming.

Frontend

• Build fast, accessible, SEO-friendly storefronts with React / Next.js (SSR/CSR as appropriate).
• Optimize Core Web Vitals, bundle size, lazy loading, and CDN strategy (Cloudflare, AWS S3).
• Write maintainable state management (Redux, Zustand, Recoil).

Code quality & collaboration

• Write clean, tested, well-structured code; review teammates' code.
• Treat unit/integration/e2e testing and CI/CD as standard practice.
• Work with Product and Design to shape requirements, not just receive them.
• Support junior engineers

Requirements

Education & Experience

• Education: Strong academic background in Computer Science, Engineering,...
• 5+ years of professional engineering with real fullstack work. We value T-shaped engineers who have a clear spike (deep expertise) in either Frontend or Backend, but possess the full-stack capability to own and ship a feature end-to-end when needed
• 2+ years building products at a product company, fast-growing tech startup, or environments demanding strong product-led delivery.
• Built or joined at least one system from scratch: schema, API, service, and UI.

Technical Depth & Domain Knowledge

We don't gate-keep on language, but you should understand the why behind your choices.

Must have at least one stack in depth:

• TypeScript / JavaScript: Node.js, React, Next.js (SSR, API routes, state management),
• Node / Go / Java: backend services, goroutines, clean service architecture
• Python: API backends, scripting, data-adjacent services
• LLM / AI integration in production features

Databases (required):

• Relational design: normalization, indexing, query optimization, transactions (PostgreSQL preferred)
• At least one NoSQL store in production (Redis, MongoDB, Elasticsearch)
• Able to diagnose and fix a slow query

System-level:

• Async systems: queues, events, background workers
• Judgment on when caching helps vs. when it creates problems
• Monolith and Microservice trade offs

Nice to have:

• eCommerce: checkout flows, inventory, pricing engines, ad integrations
• Docker, Kubernetes basics, CI/CD pipeline ownership

Benefits

• Ownership: Direct ownership of real work streams from day 1 with a clear trajectory toward product leadership roles.
• AI Implementation: Hands-on experience deploying cutting-edge AI solutions to solve high-scale business problems.
• High-performance Team: Work with a data-driven team that values autonomy, speed, and outcomes.
• Compensation: Competitive total compensation package (13 months guarantee + attractive bonus).
• Health & Leave: 15 paid leave days + global health insurance.
• Learning Budget: Dedicated L&D budget to support your professional development.