Sibi S

Senior Software Engineer — Backend

I build Python backends that keep their cool under load — from LLM-powered features to streaming APIs that stay fast when everything runs at once.

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📍 Chennai, IndiaEntropik Technologies4+ yrs experience

About

Portrait of Sibi S in a black blazer and white shirt

I'm a backend engineer with 4+ years of experience designing, building and scaling production systems in Python and FastAPI.

My work spans REST APIs, async and event-driven microservices, AI/LLM-powered features and real-time streaming endpoints, running on AWS (Lambda, DynamoDB, S3, EC2).

I'm at my best diagnosing reliability problems down at the concurrency and event-loop level, shipping AI-integrated features end to end, and working with product and frontend teams to deliver dependable, performant APIs.

  • 4+Years of experience
  • 3Featured projects
  • 0Technologies & tools

Experience

  1. Senior Software Engineer, Backend · Entropik Technologies

    May 2026 – Present

    • Architected the AI Survey service: survey, follow-up, interview and study-summary generation, with Tambo UI surfaces attached to AI responses.
    • Shipped an SSE report-streaming endpoint (plan / delta / reset / complete / error / done events) that replaced per-section polling.
    • Fixed a production outage: blocking calls in handlers serialized ~18 concurrent requests per worker and triggered gunicorn SIGKILLs at 120s. Moving to sync def handlers restored concurrency and ended the timeouts.
    • Built S3 presigned-URL attachment upload and removal flow.
    • Ran Celery workflows for more reliable background jobs and more responsive APIs.
    • Owned integrations with Microsoft Teams, Figma, ElevenLabs and 100ms.

  2. Software Engineer, Backend · Entropik Technologies

    Dec 2025 – May 2026

    • Engineered production FastAPI REST APIs for more reliable, maintainable frontend–backend communication.
    • Led third-party API integrations and contributed to microservices architecture improvements.
    • Improved API performance and reliability with Celery and better background-job handling.
    • Cut integration defects by tightening request-body schema validation, working with QA and frontend.
    • Contributed to API documentation and code-review standards.

  3. Associate Backend Developer · Entropik Technologies

    Sep 2023 – Nov 2025

    • Designed AWS solutions on Lambda, DynamoDB, EC2 and S3, improving performance and reliability by 30%.
    • Automated AWS work with Boto3 and containerized apps with Docker, cutting deployment time by 40%.
    • Raised code coverage by 25% with pytest unit and integration tests.
    • Diagnosed API bottlenecks and sped up query execution by 30%.
    • Added structured logging and monitoring to critical services; helped standardize error handling through code reviews and incident retrospectives.

  4. Programmer / Developer · Cognizant

    Mar 2021 – May 2022

    • Improved data-retrieval speed by 30% with optimized DB2 SQL queries, preserving data integrity.
    • Automated insurance renewal processing in Python, reducing manual resource needs by 40%.
    • Implemented Infrastructure as Code with CloudFormation/Terraform and documented architectures.
    • Supported UAT cycles and mentored junior developers on SQL optimization and Python scripting.

Projects

AI Survey & Reporting Platform

FastAPI platform with AI-generated survey, follow-up, interview and study-summary flows, wired to a Tambo-UI-driven frontend. Integrates ElevenLabs voice AI and Microsoft Teams, with an SSE report pipeline built for high concurrency and low latency.

  • FastAPI
  • LLM
  • SSE
  • Celery
  • ElevenLabs
  • Microsoft Teams
  • Tambo UI

Streaming Report Generation

One SSE connection delivers per-section report content as plan, delta, reset, complete, error and done events, replacing frontend polling.

  • FastAPI
  • SSE
  • anyio

Event-Loop Stall Fix

Root-caused gunicorn worker kills at 120s to blocking calls in async handlers; sync handlers on the anyio thread pool restored real concurrency.

  • Python
  • gunicorn
  • PynamoDB
  • anyio

Skills

Programming

  • Python
  • SQL
  • NumPy

Backend

  • FastAPI
  • REST APIs
  • Microservices
  • Celery
  • Async/sync concurrency
  • SSE streaming
  • anyio / thread-pool offloading

AI / GenAI

  • LLM content generation
  • Prompt-driven API design
  • Tambo UI surfaces
  • Presigned-URL attachments

Databases / Data

  • SQL
  • DB2
  • DynamoDB
  • Data pipelines
  • Data transformation

Cloud

  • AWS Lambda
  • EC2
  • S3
  • DynamoDB
  • Boto3

DevOps

  • Docker
  • Jenkins
  • CI/CD
  • Git / GitHub
  • CloudFormation
  • Terraform

Integrations

  • ElevenLabs
  • Microsoft Teams
  • Figma
  • 100ms
  • Tambo UI
PythonFastAPIAWS LambdaDynamoDBS3CeleryDockerREST APIsMicroservicesSSE streamingLLM content generationBoto3CI/CDTerraform

Education & Certifications

Master of Computer Applications

Bharathiyar University

Aug 2021 – Aug 2023

B.Sc., Computer Software Engineering

Kongu Engineering College

Jul 2018 – Sep 2020

Contact

Let's work together

Have a backend problem, an AI feature to ship, or a role in mind? I'd like to hear about it.

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