About Architecture Skills Security Work Roadmap Contact
Chennai, India  ·  Associate Software Engineer
Sweath
Kumar
Backend Systems & Security
Secure APIs .NET MAUI SQL Server AI Integration Auth Systems
See My Work Get in Touch
Chennai, Tamil Nadu
Open to opportunities
CMOTS Technologies
01  /  About Me

Who I Am &
What I Do

I build the parts of software that users never see but always feel — the systems that keep their data safe, logins secure, and apps fast. I'm an Associate Software Engineer at CMOTS Internet Technologies in Chennai.

I moved quickly from building simple features to owning entire platform migrations and security-critical API systems for real financial applications used by thousands of people.

I also run Marettype, a personal software studio, where I build developer tools. When I'm not coding, I'm solving problems on LeetCode or listening to Tamil music.

Role
Associate SDE at CMOTS Technologies
What I build
Secure APIs Mobile Apps Backend
Languages
C#.NETSQLJS
Currently
Learning AI engineering — embeddings, RAG, agents
Side project
Marettype — developer tools studio
Practice
NeetCode DSA roadmap, active daily
02  /  How I Build

The System I
Designed

Here's how a secure financial app actually works under the hood — from what the user touches to where data gets stored. Every piece has a job. ← drag to scroll

Mobile App
.NET MAUI
What the user sees
Encrypted
AES-256
Secure API
ASP.NET
Reads & writes
JWT Token
Who are you?
Auth Service
Logins, sessions
Device tracking
Dapper ORM
Get the data
SQL Server
Stores everything
Stored procs
03  /  Skills

What I Know
How to Build

Core Languages
C#●●●●○
.NET / ASP.NET●●●●○
SQL●●●○○
JavaScript●●●○○
Frameworks & Mobile
.NET MAUI
Xamarin.Forms
MVVM Pattern
REST API Design
Angular
WPF
Security & Data
JWT Auth
PBKDF2 Hashing
AES-256-GCM
Device Tracking
Dapper ORM
Stored Procs
AI Tools & Workflows
Prompt Engineering●●●●○
AI Code Review●●●●○
AI Integration●●●○○
C# / .NET
88
API Security
82
.NET MAUI
80
SQL Server
76
AI Prompting
85
04  /  Security Knowledge

I Think About
What Can Go Wrong

Most developers add security at the end. I build it in from the start. I've read real vulnerability reports and fixed actual security holes in production financial apps.

Top Mobile Security Threats I Cover
M1
Weak Password Storage
M3
Broken Login & Authorization
M5
Unsafe Network Calls (TLS)
M6
OTP Code Manipulation
M8
Rooted Device / APK Tampering
M2
Third-Party Library Risk
M4
Bad Input Handling
M10
Weak Encryption
High risk
Medium risk
How I Protect the System
01
JWT — Token-based Sessions
Each login creates a secure token. The server never stores your session — the token carries proof of who you are.
02
PBKDF2 — Password Hashing
Passwords are never stored as-is. They're run through thousands of rounds of hashing with a unique salt per user.
03
AES-256-GCM — Payload Encryption
Every request and response is encrypted. Even if someone intercepts the traffic, they can't read it.
04
Device Fingerprinting
The system remembers which devices you've logged in from. Login from a new device triggers extra checks.
05
TLS + Header Hardening
All traffic uses modern TLS. Proper security headers are enforced to prevent common browser-based attacks.
05  /  Things I've Built

Real Projects,
Real Users

01
Secure Login System for a Fintech App
Built the entire backend login and authentication system for a financial mobile app used by real investors. It handles secure sign-up, sign-in, password protection, social login (Google/Apple), and tracks which devices are accessing the account.
ASP.NET CoreJWTAES-256-GCMSQL ServerDapper
Users can sign up, log in, reset passwords, and update their profiles
Login via Google/Apple, with smart account merging if the email already exists
Every API request is encrypted — nobody can read the data in transit
Suspicious logins from unknown devices are flagged automatically
2026
02
Upgraded a Financial App from Old to New Framework
Led the migration of a production investor app from Xamarin (the old framework) to .NET MAUI (the new one). The app shows live market charts, lets users browse investment options, and handles payments — all without disrupting the existing user base.
.NET MAUIXamarin.FormsMVVMamChartsPayment Gateway
Full platform upgrade without breaking anything for existing users
Live market and company stock charts using amCharts
Complete payment flow — pick plan, pay, see result
Detects jailbroken/rooted phones for extra security
2024–25
03
Cleaned Up Financial Data APIs Across 5 Services
Five different backend services (IPO, market data, derivatives, commodities, mutual funds) were all returning data in slightly different formats — causing bugs. I standardised them all to use the same consistent response structure.
C# / ASP.NETXML Web ServicesSQL Server
Unified response format: every service now returns status, message, data
Covered all 5 financial data services in one consistent pass
2024
04
Personal Developer Tools Website
Built sweathkumar.com — a growing collection of 38+ developer tools, all in one place. Includes a live code editor (Monaco), an AI chat interface powered by the Anthropic API, and a React Native UI component showcase. Built and maintained under my studio, Marettype.
React JSXMonaco EditorAnthropic APIExpo / React Native
38+ tools, all in a single-file React architecture
Live code editor with language-specific output preview
AI chat interface connected to Anthropic's Claude API
2024–25
06  /  What I'm Good At

Three Things That
Make Me Different

01
I Think About Security First
Most developers build the feature, then add security later. I do it the other way around — I think about what could go wrong before writing a single line. This matters a lot in financial apps where a single bug can expose thousands of users.
JWTAES-256VAPTOWASP
02
I Can Debug Anything
When something breaks in a complex system, most people get lost. I can trace a problem from the user's phone screen, through the API, through the auth layer, all the way to the database — and find exactly what went wrong.
Mobile → API → DBDistributed Systems
03
I Actually Ship AI-Assisted Code
I don't just use AI to write code — I review it, debug it, fix the gaps, and ship it to production. I'm also building toward proper AI engineering: RAG pipelines, agents, and Azure deployments using Microsoft Semantic Kernel.
Prompt Eng.AI Code ReviewAnthropic API
07  /  Where I'm Headed

Learning Path to
AI Engineering

I'm not just a backend developer — I'm becoming an AI Systems Engineer. Here's the exact path I'm on. ← drag to scroll

Prompt Engineering
How to talk to AI models effectively
Done
Embeddings + Vector DBs
Teaching AI to search by meaning
Now
RAG Pipelines
AI that reads your own documents
Next
Function Calling
AI that can use real tools & APIs
Planned
AI Agents
AI that completes multi-step tasks
Planned
Local Models
Running AI privately, offline
Planned
Fine-tuning
Training AI on specific data
Planned
Azure Deployment
Shipping AI systems to production
Planned
End Goal: AI Systems Engineer
I want to combine what I already know (secure .NET backends, SQL, APIs) with AI infrastructure — to build smart, safe, production systems for the next generation of fintech and enterprise software.
08  /  Get in Touch
Let's
Talk

I'm looking for roles in fintech, banking, or AI-focused engineering teams — in Chennai or remote. If you're building something that needs secure backends, mobile apps, or AI integration, let's have a conversation.

github.com/sweathkumar linkedin.com/in/sweathkumar sweathkumar.com LeetCode / NeetCode
Best fit for roles that need
Fintech / Bankingpreferred
AI Engineeringtarget goal
Security-focused teamstrong fit
Chennai or Remoteboth open
.NET / Cloud stackalready there