Hi, my name is

Sayantan Mishra.

I build systems that scale. And think.

Senior Software Engineer with 6 years shipping high traffic backend systems in Node.js, TypeScript, and AWS. Currently building RAG pipelines and AI powered features in production, bridging robust backend engineering with modern LLM tooling.

About Me

I'm a Senior Software Engineer with over 6 years of full-time experience designing and shipping backend systems that handle serious scale. I specialise in distributed architectures, cloud infrastructure, and API design, with a track record of leading database migrations, reducing infrastructure costs, and mentoring engineering teams across fast-moving product environments.

More recently, my work has expanded into AI engineering: building a RAG-based assistant for a customer service platform, designing auto-escalation systems driven by conversation analysis, and integrating LLM tooling with production backend services. I approach AI as an engineering discipline: the same rigour around reliability, observability, and data integrity that I apply to any backend system.

Here are some of the technologies I've been working with:

  • ▹ Node.js / TypeScript
  • ▹ PostgreSQL · MySQL · MongoDB
  • ▹ AWS (Lambda, ECS, SQS, RDS)
  • ▹ Microservices & Distributed Systems
  • ▹ RAG Pipelines & LLM Integration
  • ▹ GraphQL · REST APIs
  • ▹ Redis · Caching Strategies
  • ▹ Terraform / Serverless
~/sayantan

Where I've Worked

Senior Software Engineer — Backend & AI  @  Recrosoft Private Limited

April 2025 – Present

  • ▹ Led technical design and architecture for a RAG-based AI assistant that helps customer service agents retrieve contextually relevant information in real time.
  • ▹ Built an auto-escalation engine that analyses conversation state and message sentiment to trigger escalations, reducing manual triage effort significantly.
  • ▹ Optimised PostgreSQL performance through targeted query rewriting and indexing strategies; led Prisma ORM and PostgreSQL version upgrades with zero downtime.
  • ▹ Implemented data archival and indexing pipelines to reduce storage costs while keeping query performance fast.
  • ▹ Integrated third-party calendar and notification services, and delivered high-stakes external API integrations end-to-end.
  • ▹ Mentored junior engineers on backend best practices, code quality, and cloud deployment patterns on GCP.

Software Engineer — Backend  @  Onmobile Global Ltd.

Nov 2021 – March 2025

  • ▹ Architected and maintained a microservices-based gaming platform (onmo.com) serving high-traffic SaaS workloads across multiple regions.
  • ▹ Designed and executed a complex database migration from DynamoDB to MySQL across environments using Knex.js — zero data loss, zero downtime.
  • ▹ Built a strategic Redis caching layer using Hashes, Sorted Sets, and Lua scripting that reduced direct database load by 60%.
  • ▹ Implemented Full Text Search in MySQL for user name lookup, cutting overall DB CPU utilisation by 25% and eliminating query spikes.
  • ▹ Built an in-house event processing system (Kafka-equivalent) on AWS SQS + Lambda + MongoDB for background synchronous and asynchronous event handling.
  • ▹ Deployed worker infrastructure for scheduled caching and migrations using ECS and EventBridge, managed with Terraform and Terragrunt.
  • ▹ Integrated an ETL pipeline with Apache Airflow and dbt; led code reviews and established engineering best practices across the team.

Trainee Software Engineer — Full Stack  @  Mantra Labs Pvt. Ltd.

Sept 2020 – Nov 2021

  • ▹ Developed and maintained a production chatbot platform for a major health insurance company using Java Spring Boot microservices and Node.js.
  • ▹ Built real-time communication features using socket.io and Redis, improving chatbot responsiveness under concurrent user load.
  • ▹ Integrated the chatbot with multiple external CMS APIs to surface policy data dynamically to agents and customers.
  • ▹ Addressed monthly VAPT (Vulnerability Assessment and Penetration Testing) findings, proactively resolving security issues before release.
  • ▹ Managed and stored large volumes of customer data, enabling agents to run detailed analytics and reach prospective customers.

Software Engineer — Backend  @  OneDred Pvt. Ltd.

June 2019 – Dec 2019

  • ▹ Built REST APIs for real-time vehicle location tracking using Node.js and Express, with data persisted in MongoDB and deployed on AWS EC2.
  • ▹ Supported the SEO team by resolving bugs and implementing WordPress themes and plugins, improving overall site performance.

Something I've Built

Hotel Management Dashboard screenshot

Featured Project

Hotel Management Dashboard

A comprehensive hotel and accommodation management platform backed by MongoDB and secured via Google SSO. The booking system acts as a synchronisation hub, processing drag-and-dropped Excel exports from Booking.com, intelligently parsing reservations to add new bookings and update existing ones without duplication. The invoicing system tracks advance payments, flags pending balances in a dedicated queue, and generates downloadable PDF invoices for guests. A unified management interface oversees the complete guest lifecycle: room allocations, guest counts, commissions, check-in/out statuses, and automated WhatsApp notifications.
  • MongoDB
  • Google SSO
  • Node.js
  • Excel Parsing
  • PDF Generation
  • WhatsApp API