name:
Sunil Kalikayi
role:
Backend Engineer · System Architecture
about:
explore:
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01
About
3+
Years Building Production Systems
60+
Countries Served
Dev Lead
Promoted for Ownership
I build backend systems that stay reliable under load and remain maintainable over time. With 3+ years owning production systems, my focus is on transactional integrity, structured API design, and clean separation of concerns.
My approach starts at the database. Schema design, indexing strategies, and transaction isolation decisions come before writing a single line of application code. A well-modeled data layer prevents entire categories of bugs from ever reaching production.
I work primarily with NestJS and PostgreSQL, building systems where concurrency is a first-class concern — not an afterthought. From conflict-free bed-level booking allocation to multi-region e-commerce platforms, I design for correctness first, then optimize for performance.
Clean Architecture isn’t just a pattern I follow — it’s how I think about ownership. Controllers handle requests. Services own business logic. DTOs validate boundaries. Every layer evolves independently.
02
Tech Stack
Backend
Database
Architecture
Tools
03
Projects
Systems and products I've designed, built, and owned end-to-end.
FreeResumePick — Free Resume Builder
A free online resume builder that lets users create, customize, and export professional resumes without signing up. All data stays in the browser with 10 professional templates and multi-format export.
- Built 10 professional resume templates with live real-time preview
- Implemented multi-format export supporting PDF, DOCX, and PNG downloads
- Designed zero-auth architecture using Zustand with localStorage persistence
- Added ATS score checker with optimization tips panel
- Built social sharing flow and welcome onboarding experience
- Full SEO implementation with JSON-LD structured data and sitemap
04
Architecture Thinking
How I approach system design decisions.
API Design
REST APIs structured around domain boundaries. Each module owns its controllers, services, and DTOs — keeping endpoints predictable and independently testable.
Database Schema Modeling
Schema-first approach: data models designed before application logic. Normalization, constraints, and enum types are deliberate design-phase decisions.
Indexing Strategies
Composite indexes for multi-column filters, partial indexes for conditional lookups. Every index earns its place through measured query performance.
Concurrency Handling
Row-level locking, optimistic concurrency patterns, and serializable transactions. The booking platform handles simultaneous requests without double-booking.
Transaction Isolation
Atomic operations for booking workflows, read-committed for general queries, serializable for inventory-critical paths. Boundaries drawn carefully.
RBAC Structuring
Role hierarchies with granular permissions. Guards and decorators enforce access at the route level, keeping auth logic out of business services.
Error Handling
Centralized exception filters with structured responses. Business errors are domain-typed, validation errors surface field-level detail.
Observability
Structured logging with correlation IDs. Critical paths log entry, exit, and failure — enabling post-incident analysis without noise.
Scalability
Stateless services, connection pooling, query optimization, and caching — planned before traffic demands them, not in response to outages.
05
Leadership & Practices
Promoted to Development Lead
Recognized for consistent delivery and system ownership. Took on responsibility for production stability, team coordination, and technical direction.
Mentoring Engineers
Guiding junior developers on backend patterns, clean architecture practices, and writing production-ready code that lasts beyond the sprint.
Code Reviews
Conducting thorough code reviews focused on correctness, readability, and maintainability. Enforcing consistent patterns across the codebase.
Clean Coding Standards
Establishing and enforcing coding standards — structured DTOs, typed responses, consistent error handling, and clear module boundaries.
Production Stability
Owning production health — monitoring deployments, resolving incidents, and ensuring systems remain stable under real-world traffic patterns.
Backend Roadmap Ownership
Driving backend technical decisions, architecture discussions, and feature planning in alignment with product goals and team capacity.
06
Get in Touch
Open to opportunities where I can own backend systems and contribute to products at scale. If you're building something that demands reliable, well-architected infrastructure — let's talk.
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