Available for US Remote Consulting

I architect enterprise
platforms that handle
real stakes.

Real money. Real users. Real regulatory pressure. 8+ years building mission-critical systems in InsurTech & Financial Services.

Download CV Let's Work Together
0+
Years Experience
0K+
Users Served
0%
DB Perf Gain
0B+
NPR Assets
.NET 10/8 LTS
C# / ASP.NET Core
Azure Cloud
Semantic Kernel
ML.NET
Oracle / SQL Server
Duende IdentityServer
Docker / Kubernetes
Domain-Driven Design
Zero-Trust Security
CQRS / Event-Driven
RAG / Vector DBs
Terraform / IaC
OpenTelemetry
gRPC / REST APIs
About

Designing systems
that endure

Rahul Karn — Enterprise Systems Architect

Rahul Karn

Enterprise Systems Architect

Kathmandu, Nepal

Enterprise Systems Architect with 8+ years designing, building, and modernizing mission-critical platforms in insurance and financial services. I architect new systems from the ground up, modernize legacy platforms to .NET 10/8 LTS and cloud-native stacks, and embed AI/ML into core business workflows — underwriting, claims, fraud detection, and predictive analytics.

Engagements produce production-ready system designs: C4 blueprints, domain models, security architectures, data platform strategies, and phased execution plans. Proven at scale: a 90,000+ user platform, 50% database performance gains, NPR 100B+ asset portfolio systems, and 6+ engineer teams guided through complex transformations.

Based in Kathmandu, I've been deep in Nepal's insurance infrastructure since 2017 — working US-Eastern hours and shipping systems that handle real money, real users, and real regulatory scrutiny.

Case Studies

Architecture in
practice

Real problems, real constraints, real outcomes. Each case represents production systems handling regulated financial operations.

90K-User Enterprise Portal — From Monolith to Modular

Architected the complete platform serving 90,000+ users across policy, claims, and agent workflows.

90K+ UsersMonolith → ModularRBACOWASP
Challenge

Legacy monolithic insurance platform couldn't scale, had no API layer, security was bolt-on, and adding features meant touching everything. 90,000+ users depended on it daily.

Simplified Architecture — C4 Container View
Agents / Customers90K+ users
Admin PortalInternal ops
Digital ChannelsWeb / Mobile
HTTPS / API Gateway
API GatewayYARP Reverse Proxy
Bounded Contexts
Service Layer
Policy AdminLifecycle mgmt
UnderwritingRisk assessment
ClaimsProcessing
Agent MgmtOnboarding / KYC
EF Core / Repository Pattern
Data Layer
Oracle DBLegacy data
SQL ServerNew modules
Identity ServerOAuth2 / OIDC
Approach

Defined bounded contexts using domain-driven design. Drew service boundaries around underwriting, policy admin, claims, and agent management. Designed API-first contracts with versioning. Implemented RBAC with Duende IdentityServer (OAuth2/OIDC, BFF pattern, reference tokens).

Key Decisions
  • Phased migration: monolith → modular monolith → microservices-ready (not big-bang)
  • YARP reverse proxy as API gateway (lightweight, .NET-native)
  • Domain-driven bounded contexts with explicit integration contracts
  • OWASP Top 10 aligned security controls at every layer
  • RBAC model supporting 5,000+ agents, 85,000+ customers, internal ops
  • API versioning + backward compatibility policy (zero breaking changes)
Outcome

Production platform serving 90,000+ users. New features ship without full regression. Security audit-ready. API ecosystem enables digital channel expansion. 6+ engineers working in parallel without stepping on each other.

50% Database Performance Gain — Oracle/SQL Server at Scale

Systematic performance engineering across the entire insurance data layer, cutting query times in half.

50% FasterP95 1200ms → 580msOracle + SQL Server
Challenge

Insurance platform's database layer was the bottleneck. Premium calculation engine timing out during peak loads. Query response times degrading as data grew. DB CPU regularly hitting 90%+.

Approach

Ran a systematic database performance audit — captured execution plans, identified missing/redundant indexes, found expensive table scans in stored procedures, and mapped query patterns against actual workload.

Key Decisions
  • Rewrote critical stored procedures (eliminated cursor/loop patterns, moved to set-based operations)
  • Redesigned indexing strategy based on actual query patterns (covering indexes for hot queries)
  • Fixed parameter sniffing patterns where applicable
  • Verified with actual execution plans + IO/time stats
  • .NET side: reduced over-fetching (DTO shaping), async + cancellation tokens, connection pooling
  • Set up SLO definitions + monitoring dashboards for ongoing regression detection
Outcome

50% reduction in query response times. Directly improved throughput for premium calculation engine across 20+ product lines.

P95 Query Latency
1,200ms→580ms
DB CPU Peak
92%→54%
Timeout Incidents / Week
12+→<1
Peak Hour Throughput
1×→2×

Billion-Rupee Payment Architecture — Transaction Integrity at Scale

Reliable payment flows for NPR 100B+ transaction volumes with zero duplicates and full auditability.

NPR 100B+Zero DuplicatesFull Auditability
Challenge

NPR 100B+ in asset portfolio transactions — premium collections, policy payouts, agent commissions. Existing flow had no reconciliation, no idempotency, failures tracked in spreadsheets.

Payment State Machine — Transaction Lifecycle
Client RequestPremium / Payout
Idempotency Key
InitiatedIdempotency check
Gateway API
AuthorizedGateway confirmed
Capture / Settle
SettledReconciled
FailedRetry queue
RefundedAudit logged
Reconciliation Layer
Auto ReconciliationNear-real-time
Audit TrailImmutable logs
AlertingMismatch detection
Approach

Designed end-to-end payment gateway integration with "nothing gets lost" principle. Mapped every transaction state, idempotency, reconciliation patterns, and complete audit trail logging.

Key Decisions
  • Idempotency keys on every payment request (prevents double-charge)
  • Payment state machine: Initiated → Authorized → Captured → Settled / Failed / Refunded
  • Webhook/callback flows with retry logic + exponential backoff + circuit breakers
  • Automated reconciliation comparing gateway records with internal state
  • Audit logging for regulatory compliance — immutable logs, correlation IDs
  • Security: tokenization, avoid storing PAN, least privilege, secret management
Duplicate Rate
~0.3%→0%
Reconciliation Time
2 days→Real-time
Failed Payment Recovery
Days→Minutes
Audit Prep Time
2 weeks→1 day
What You Get

Production-ready
deliverables

Every engagement produces tangible architecture artifacts — not slide decks with boxes and arrows that collect dust.

System Architecture

C4 diagrams, domain models, capability maps, service boundaries, and data ownership matrices.

C4 Context / Container / Component Domain Model & Bounded Contexts 15+ ADRs per engagement

Security & API Design

OWASP-aligned security controls, RBAC/ABAC models, API governance, threat models, compliance checklists.

API Versioning & Error Model STRIDE Threat Model Templates RBAC Design Documents

AI & Transformation

Executive AI use-case playbooks, modernization plans with business cases, phased timelines, ROI projections.

AI Use-Case Roadmap ML Integration Architecture 12-Month Scalability Plan
Expertise

Architecture & design
competencies

System Design

Greenfield and brownfield architecture, DDD, capability mapping, bounded contexts, event-driven/CQRS patterns, GoF design patterns.

DDDC4 ModelCQRSEvent-DrivenADRs

AI/ML Architecture

ML pipeline design for insurance/finance — fraud detection, predictive underwriting, claims automation, risk scoring with RAG and Semantic Kernel.

ML.NETRAGSemantic KernelPythonVector DBs

Security & Compliance

Zero-trust design, RBAC/ABAC, OAuth2/OIDC, OWASP Top 10, STRIDE threat modeling, encryption, secrets management, audit trails.

Zero-TrustOAuth2OWASPSTRIDEmTLS

Platform & Data

API-first design, gateway patterns, idempotency, payment protocols, database architecture, query optimization, ETL/ELT, capacity planning.

API-FirstOracleSQL ServerAzure SQLETL

InsurTech & FinServ

Core insurance systems — underwriting, policy admin, claims, payments, asset management, premium engines, KYC/AML, digital channels.

InsuranceClaimsUnderwritingPaymentsKYC

Cloud & DevOps

Azure (App Services, Functions, Key Vault, AD), Docker, Kubernetes, CI/CD pipelines, Terraform, Infrastructure as Code, observability.

AzureDockerK8sTerraformCI/CD
Experience

Professional
journey

Officer — Lead Architect & Platform Engineer

Nepal Life Insurance Co. Ltd. · Kathmandu, Nepal

Jan 2023 – PresentCurrent
Platform Architecture & AI-Driven TransformationJul 2024 – Present
  • System design leadership: Architect and lead development of mission-critical insurance platform modules (policy administration, underwriting, claims, digital channels).
  • AI/ML strategy: Designed AI roadmap for insurance operations — fraud detection, predictive underwriting, claims triage automation; authored executive use-case playbook.
  • Digital transformation: Drove enterprise-wide system modernization — digitized policy issuance, claims processing, agent onboarding; designed SLA frameworks.
  • Performance & cost architecture: Led database performance programs and infrastructure cost-efficiency initiatives delivering measurable savings.
System Architecture & Secure Platform DeliveryJan 2023 – Jun 2024
  • Platform modernization: Designed target-state architecture; created phased migration roadmap (monolith → modular → microservices-ready), guiding 6+ engineers.
  • Secure platform: Delivered enterprise portal and API ecosystem serving 90,000+ active users; architected RBAC, API governance, OWASP-aligned security.
  • Transaction architecture: Designed payment gateway flows with reconciliation patterns, idempotency. Delivered 50% query-time reduction.
90K+ Users50% Perf GainAI Roadmap6+ Engineers

Software Engineer

Nepal Life Insurance Co. Ltd. · Kathmandu, Nepal

Nov 2018 – Dec 2022
  • Designed and built enterprise applications for asset management (NPR 100B+ portfolio), policy admin, and premium calculation using .NET Core with Oracle/SQL Server.
  • Led development of premium calculator engine across 20+ product lines; standardized actuarial rules, improving sales efficiency by ~30%.
  • Designed secure onboarding system for 5,000+ agents/customers with KYC workflows and payment gateway integration.
  • Built API integrations connecting underwriting, policy issuance, and claims across core systems.
NPR 100B+ Portfolio20+ Product Lines30% Efficiency Gain

Software Engineer

Innovative Ghar Nepal · Kathmandu, Nepal

Oct 2017 – Nov 2018
  • Owned end-to-end system design of a multi-tenant real-estate platform (ASP.NET MVC/C#); designed data model, repository-pattern architecture, RBAC, and shipped property listing, tenant management, and reporting modules.
Academic Background

Education &
certifications

In Progress2025 – 2027

MSc, Data Science & Computational Intelligence

Coventry University, UK (Distance)

Softwarica College · Expected Feb 2027

In Progress2024 – 2026

MBA, Finance

Indira Gandhi National Open University

Distance · Expected Jul 2026

Completed2013 – 2017

BE, Computer Science & Engineering

Advanced College of Engineering

Tribhuvan University

IEEE Publication: "Attendance and Security Assurance using Image Processing" — ICCMC 2018 · View on IEEE Xplore →

In Progress2025

Microsoft Certified: Azure Solutions Architect Expert

Microsoft — AZ-305

Cloud Architecture Certification

Contact

Let's build
something remarkable

Available for US remote consulting in InsurTech, Financial Services, and AI-Driven Transformation.

4h+ US Eastern overlap · Independent Contractor
Email[email protected]
Phone+977 9863036368
LinkedInlinkedin.com/in/rahulkarn52
Websitexraone.com