// Senior Backend Engineer
I build, scale and own the backend systems that products run on.
Python · Django · FastAPI · Flask · PostgreSQL · AWS · Docker · Celery · Redis · AI/LLM Integration
About
Senior backend engineer specializing in Python — Django, FastAPI and Flask. I focus on clean APIs, solid architecture and AI/LLM features that ship to production and stay reliable. Top Rated Plus on Upwork with 6,200+ hours, a 100% Job Success Score and $90K+ earned — mostly long-term engagements where clients trust me to own their backend end to end.
Core Stack
// Reach into React when the job calls for it.
// 5+ years shipping production Python backends.
How I Can Help
Designing and building scalable production backends from scratch in Python (Django, FastAPI, Flask) — clean REST APIs, third-party integrations, webhook systems, real-time WebSocket features, multi-service architectures, and task queue infrastructure built to handle real load.
Bringing OpenAI, Anthropic, and open-source LLMs into real products — RAG pipelines, vector search, embeddings, prompt engineering, Voice AI (ElevenLabs, Whisper, BlandAI), and agentic workflows that are shipped and reliable, not just proof-of-concepts.
Adapting pre-trained models to domain-specific tasks through fine-tuning, and building evaluation and RLHF-style pipelines to measure quality, catch regressions, and validate model behaviour before it ships.
Taking over messy, half-finished, or struggling codebases and getting them stable, scalable, and live in production. Diagnosing and fixing N+1 queries, cache bottlenecks, blocking I/O, unstable deployments, and slow search — including Elasticsearch migrations for systems that have outgrown basic SQL queries.
AWS architecture (EC2, RDS, S3, Lambda), Docker containerisation, CI/CD pipelines, and production deployment. The infrastructure layer that keeps your backend reliable, observable, and easy to ship to.
Senior Python code review, architecture guidance, and consulting — surfacing performance bottlenecks, security gaps, and design issues before they reach production. Includes LLM evaluation pipeline design and data quality review.
Upwork credentials, publicly verifiable
Top Rated Plus
on Upwork
6,200+
Hours Billed
100%
Job Success Score
$90K+
Total Earned
Selected Work
Medius AI tackles one of Indian banking's biggest problems — billions locked in non-performing loans — using AI to predict, engage, and recover. I led the backend that makes it run, live in production with real banks and NBFCs.
Meomind makes therapy more affordable and accessible through an AI-powered platform — a large library of real therapy sessions plus assessments, journaling, and guided tools. I lead its backend.
AI models are only as good as the data behind them. I worked as a senior reviewer auditing AI-generated Python code inside an LLM training pipeline — the quality gate that keeps model training honest.
Client Reviews
Verified reviews from Upwork and direct clients
Sourav is highly experienced, deadline oriented, very hard working & extremely talented lead developer. He did an exceptional job on all the given projects. His contribution in building Medius has been immense.
Sourav demonstrated good design skills with a self-motivated attitude. His performance exceeded expectations and was able to complete the project successfully on time.
Good freelancer. Quick turnaround. Hope to work with him again.
Sourav worked with us as a freelance web design and backend developer, and throughout the engagement we found him sincere, committed, and result-oriented. He brought strong technical skills to the table, delivered clean and reliable work, and consistently approached problems with a solutions-first mindset. A dependable developer we'd happily work with again.
Really good developer, I will work with him in future too.
Sourav is a commensurate, experienced professional. Despite the chaotic nature of the project, he was able to complete the project tasks and went above and beyond to do so. I unhesitatingly recommend Sourav to anyone looking for an expert in backend development.
Pleasure to work with.
In the starting days itself, Sourav started showing great coding skills. We found him really hardworking. Due to his commitment, our product was ready and launched on time.
Contact
I take on a small number of engagements at a time and focus on long-term partnerships. If you have a backend project that needs a senior engineer you can rely on, get in touch.