SBSachin Budania
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Full Stack Software Engineer & Backend Architect

Hi, I'm Sachin Budania.

I build scalable backend systems, cloud architectures, and full-stack web applications. Specialized in Python (Django, DRF, Celery), AWS cloud services, and modern TypeScript (Next.js, React).

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Backend Architecture
AWS Cloud (ECS, Lambda, S3)
Distributed Tasks (Celery)
Multi-Tenant SaaS & Stripe
Next.js 16 & TypeScript
REST & OpenAPI Systems
Sachin Budania
Sachin Budania
Open to Remote & Hybrid
01 / PROJECTS

Selected Work & Architecture.

Live web applications, interactive Swagger API docs, and codebases.

Full Stack SaaSFull Stack Software Engineer

Covert SaaS & Multi-Tenant Engine

A multi-tenant SaaS application built with Next.js 16 and Django REST Framework. Implements HttpOnly rotating JWT cookie sessions, an Axios anti-storm queue, Google OAuth 2.0 PKCE, and full-lifecycle Stripe recurring billing with webhook event synchronization.

Architecture Highlights:
Silent JWT rotation in HttpOnly, SameSite=None, Secure cookies to prevent XSS token exposure
Axios promise-queue interceptor preventing duplicate 401 token refresh storms during expired sessions
Stripe customer and subscription synchronization via dj-stripe and webhook handlers
Custom allauth account adapter integrated with SendPulse REST API for transactional activation emails
Token Lifecycles
15m / 7d
Auth Flow
Google PKCE
Billing Engine
Stripe + dj-stripe
Infrastructure
Cloudflare + Nginx
Django 5.2DRF 3.16Next.js 16React 19TypeScriptTailwind v4StripeZustandPostgreSQL
Live DemoAPI HostSource Code
Interface Preview
Covert SaaS & Multi-Tenant Engine previewOpen Demo
02 / ARCHITECTURE DECISIONS

Engineering Decisions & Trade-Offs.

How system bottlenecks were analyzed, decoupled, and implemented.

Data Ingestion
Problem:

Processing 30MB+ CSV/JSON movie catalogs without blocking HTTP request workers or exceeding memory limits.

Standard Approach

Synchronous in-memory parsing inside request-response cycle, causing HTTP timeouts and memory spikes.

Implemented Solution

Streaming directly to S3, then dispatching a Celery Canvas chain: partition into 1MB chunk files, execute parallel worker group, and clean temporary S3 artifacts.

Impact:Fast API response times, bounded worker memory, and horizontal scale across worker pools.
ML Vectorization
Problem:

Calculating high-dimensional text vectors and Cosine Similarity matrices without CPU starvation on web servers.

Standard Approach

Computing CountVectorizer matrices and cosine angles directly on Gunicorn web worker threads.

Implemented Solution

Decoupled serverless AWS Lambda microservice invoked on demand via API Gateway, keeping web workers purely I/O bound.

Impact:Zero CPU degradation on web tiers, auto-scaled compute on demand, and isolated ML dependencies.
Session & Token Security
Problem:

Multiple parallel frontend API requests receiving 401 responses simultaneously, triggering a storm of duplicate refresh requests.

Standard Approach

Standard axios 401 interceptor that fires /token/refresh/ for every failed request concurrently.

Implemented Solution

Axios Promise-Queue Interceptor: buffers concurrent requests in a promise queue, executes single refresh, and replays all queued calls with new credentials.

Impact:Reliable cookie session persistence, zero race conditions, and HttpOnly XSS protection.
Database State Integrity
Problem:

Simultaneous user preference updates and watch history writes causing lost updates or inconsistent recommendation vector states.

Standard Approach

Standard ORM save() operations vulnerable to interleaved writes and race conditions.

Implemented Solution

Atomic transactions (transaction.atomic) combined with database row-level locking (select_for_update) during preference aggregation.

Impact:ACID data integrity under concurrent write loads with minimal lock contention duration.
03 / TECHNICAL STACK

Technologies & Tools.

Core technologies and services used across backend, cloud, and frontend projects.

Backend & Distributed Systems
BACKEND
Python 3.13AsyncIO, Typing, uv
Django & DRFv6.0 & v5.2, REST API, Auth
Celery 5.6Distributed Tasks, Canvas
FastAPI / FlaskMicroservices & ASGI
Gunicorn / WSGIWorker orchestration
OpenAPI 3.0 / Swaggerdrf-spectacular specs
Cloud Infrastructure & DevOps
INFRASTRUCTURE
AWS ECS FargateServerless container tasks
AWS LambdaServerless compute
AWS S3 / SQSObject storage & queues
DockerMulti-stage container builds
Astral uvFast Python packaging
AWS Secrets ManagerCredential management
Frontend Engineering & UI
FRONTEND
Next.js 16App Router, RSC, Turbopack
React 19Concurrent hooks & context
TypeScript 5Strict type safety
Tailwind CSS v4Design tokens & utilities
Motion 12UI interaction & physics
Radix UI PrimitivesAccessible components
Databases, ML & Integrations
DATA & INTEGRATIONS
PostgreSQLSchema design & row locks
RedisTask broker & cache
Scikit-LearnCountVectorizer & Cosine Sim
NLTKWordNet lemmatization
Stripe & dj-stripeSubscriptions & webhooks
SendPulse APITransactional emails
05 / CONTACT

Get in Touch.

For software engineering roles, backend architecture discussions, or collaboration inquiries.

Response turnaround: within 24 hours
Open to Remote & Hybrid opportunities
Contact Channels
Send Email
GitHub Profile
Resume PDF