Rupanjana
Mitra

Backend & Systems Engineer who builds pricing engines

I build backend systems for business-critical commercial workflows — the pricing, approval and payment paths a company cannot afford to get wrong. I care about correctness, and about the person who has to run this at 2am.

(the drawings are the best part — keep scrolling)

a house, some birds, a very large sun

things I made

Selected work

Backend systems where being wrong is expensive. These show how I think about a problem, not just which tools I know.

Pricing & Workflow Engine

2026

A backend system that replaced manual pricing workflows with rule-based computation and validation. Configurable pricing rules, multi-step approval flows, and data models designed so that a wrong number simply cannot get through.

Correctness enforced by validation layers and deterministic processing, exercised against simulated real-world usage.

  • Java
  • Spring Boot
  • PostgreSQL

Payment Processing & Reconciliation Service

2026

A service modelling real payment flows end to end — order creation, payment initiation, status tracking. Idempotent APIs so retries never double-charge, and asynchronous reconciliation that pulls system and payment state back together.

Failure scenarios modelled explicitly, with retry-driven eventual consistency.

  • Java
  • Spring Boot
  • PostgreSQL

KDE Sheets — Google Summer of Code

2014

Built user-facing UI features for KDE Sheets as a Google Summer of Code intern, working with open-source maintainers across the world on feature design and code review.

  • C++
  • KDE
  • Open Source

who's behind all this

About me

I'm a backend engineer. Most of what I've built lives out of sight: pricing engines, approval flows, payment reconciliation — the machinery underneath a business, where being wrong is expensive and being unpredictable is worse.

My favourite kind of work is taking something error-prone and manual and making it deterministic. At Encon I replaced spreadsheet-driven costing with real systems, and watched offer turnaround drop by 70% and manual errors by 75%. I own the whole lifecycle — architecture, deployment, monitoring, and the 2am pages.

I took a long break between 2018 and 2025 for my mental health. I'm not shy about it: it's the reason I build the way I do now — sustainably, honestly, and with a lot of care for the humans on the other side of the system.

Away from the terminal I'm the one with the crayons. The drawings scattered around this site are the good stuff — made by small people who have not yet been told what colour a sky has to be.

70%

Faster offer turnaround

75%

Fewer manual errors

2014

Google Summer of Code

B.Tech in Computer Science and Engineering

National Institute of Technology Durgapur, India

Aug 2011 — May 2015

the gallery ↓

home
the big tree
after rain
for you

the unprofessional bit

Who I am

I have worn multiple hats — from being a fairly successful Airbnb host with 200+ reviews, to being a fitness coach, a Math tutor, driving Uber, working as a tour guide, waiting tables in a high-end restaurant, and selling food on the street.

I took up these jobs during my career break so I wouldn't have to depend on my parents' money, though they have been supportive of all my decisions. I get impatient if I'm not doing enough with my time. I like to try new things and see where they go. I can be very pragmatic without losing the bigger vision at its core.

every hat, so far ↓

  • Airbnb host200+ reviews
  • Fitness coach
  • Math tutor
  • Uber driver
  • Tour guide
  • Waiterhigh-end restaurant
  • Street food seller

The Economic Times

featured for resilience

What we did was to survive.

Well — that's enough.

my favourite line

what's in the pencil case

Skills

Languages

  • Java
  • Python
  • C++
  • SQL
  • JavaScript

Frameworks

  • Spring Boot
  • Spring Security

Systems

  • Distributed Systems
  • Concurrency
  • Fault Tolerance

Tools

  • PostgreSQL
  • Redis
  • Docker
  • Git
  • GCP

how I got here

Experience

  1. Senior Software Engineer — Backend & Systems

    Jan 2026 — Present

    Encon Thermal Engineering Pvt. Ltd. · Panjim, India

    • Designed and deployed backend systems replacing spreadsheet-driven costing and offer workflows.
    • Reduced offer turnaround time by 70% and manual errors by 75%.
    • Owned system architecture, deployment, monitoring, and operational support.
    • Worked closely with business stakeholders to translate pricing and commercial requirements into system design.
  2. Career Break — Mental Health & Well-Being

    Aug 2018 — Dec 2025

    • Took a structured break to prioritise mental health and long-term sustainability.
    • Stayed self-supporting throughout: Airbnb host with 200+ reviews, fitness coach, Math tutor, Uber driver, tour guide, waiter, and street food seller.
    • Featured in The Economic Times for resilience.
  3. Software Engineer

    Jan 2016 — Jul 2018

    BillDesk · Mumbai, India

    • Developed Java and Spring backend services for internal payment systems.
    • Optimised PostgreSQL schemas for transactional correctness and reporting.
  4. Google Summer of Code Intern — KDE Sheets

    May 2014 — Sep 2014

    KDE · Remote

    • Implemented user-facing UI features for KDE Sheets as part of Google Summer of Code.
    • Collaborated with global open-source maintainers on feature design and code reviews.

the bit where you say hello

Let's build something that holds up

I'm open to backend and systems roles, and to collaborations where correctness actually matters. Email is the fastest way to reach me — I reply to everything.

thanks for scrolling all the way down