Nilanjan NathBackend / Payments / Infra

reconciling…

000

Backend engineer · founding engineer · Tripura, India

NilanjanNath

I love building scalable systems, and I'm always learning how to build them better.

currently intoscale
Now showingQR ordering for cafés

Table 7 · scan

Masala chai ×2
Veg sandwich
Cold coffee
Order

Counter

#0142

4 items

Kitchen

Ready

Python✦Django✦Flask✦PostgreSQL✦Redis✦Cashfree✦ONDC✦Docker✦Jenkins✦GitLab✦Azure✦Node.js✦React✦Next.js✦Tailwind✦Python✦Django✦Flask✦PostgreSQL✦Redis✦Cashfree✦ONDC✦Docker✦Jenkins✦GitLab✦Azure✦Node.js✦React✦Next.js✦Tailwind✦
Python✦Django✦Flask✦PostgreSQL✦Redis✦Cashfree✦ONDC✦Docker✦Jenkins✦GitLab✦Azure✦Node.js✦React✦Next.js✦Tailwind✦Python✦Django✦Flask✦PostgreSQL✦Redis✦Cashfree✦ONDC✦Docker✦Jenkins✦GitLab✦Azure✦Node.js✦React✦Next.js✦Tailwind✦
01About

0

tickets booked a day

on the Reker backend

0+

bookings since launch

May 2026 → today

0

restaurants live

on BurpnBill, solo build

0 yrs

shipping to production

intern → founding engineer

I care about the unglamorous parts that decide whether software is trusted: idempotent payment flows, race conditions, reconciliation you can audit, and deployments that are boring on purpose.

Python and Django are home turf, with Redis and Postgres around them. I also ship the frontend and the infrastructure when a project needs one person who can take it from idea to a live URL.

02Experience

Where I've shipped

Sep 2026 — NowRemote

Freelance Full-Stack Developer

Freelance

Designing, building and deploying BurpnBill, a QR ordering and billing product for cafés. Solo, end to end, live in 2 restaurants.

  • Table QR → phone ordering → counter approval → live kitchen board → bill.
  • Frozen-snapshot bills with an optional GST split and public receipts.
  • Tenant isolation, idempotent orders, rate limiting, 23 test files on real Postgres.
Nov 2024 — Sep 2026Bengaluru

SDE-1, Founding Engineer

Reker · Evolvevol Tech

One of two backend engineers for most of the tenure. Started as an intern, owned the backend, payments and DevOps of a metro-booking app.

  • ONDC (TRV11) booking flow with Namma Metro (BMRCL), ~300 tickets a day.
  • Cashfree payments, refunds and payouts; T+1 settlement and reconciliation.
  • Namma Pass wallet, ride packs, rate limiter, GitHub → GitLab, Actions → Jenkins, Docker on Azure.
Jan — Jun 2024Bengaluru · Remote

SDE Intern

Y4E · Yclept 4E Labs

Where it started: Django REST APIs, PostgreSQL, and an Android client in Java with Retrofit and Google Maps.

2023 — 2024Guwahati

Web Development Head

GDSC · Assam Downtown University

Led a 4-person team, ran developer workshops, and reached the Kavach National Cybersecurity Hackathon grand finale as the only team from the Northeast.

EducationBCA · Assam Downtown University · 2021 – 2024Kavach Hackathon 2023 · Grand Finalist
03Selected work

01 — Founding engineer · Reker

Metro tickets, on ONDC

The backend behind a Bengaluru metro-booking app: from the ONDC booking flow to the money that reaches the metro operator the next day.

  • ONDC (TRV11) search → select → init → confirm → cancel, with refunds.
  • Cashfree payments, refunds and payouts, with signed webhooks.
  • T+1 settlement and reconciliation with the metro operator.
  • Namma Pass wallet, ride packs, rate limiting and the CI/CD under all of it.
DjangoFlaskRedisPostgreSQLCashfreeJenkinsAzure
metro-tickets,-on-ondc.live
1
Search
2
Select & init
3
Pay
4
ONDC confirm
5
Ticket issued

payments

Cashfree · signed, idempotent webhooks

money movement

refunds · payouts · T+1 reconciliation

02 — Freelance · solo build

BurpnBill

QR table ordering and billing for cafés. A customer scans, orders, the counter approves, the kitchen sees it live, and staff settle the bill. Live in 2 restaurants.

  • Self-serve café signup, staff invites, menu with photos, printable QR sheets.
  • Bills are frozen snapshots with an optional GST split and public receipts.
  • Tenant isolation on every query, idempotent orders, 23 test files on real Postgres.
Node.jsExpressReactPostgreSQLSupabaseTailwindAWS Lightsail
burpnbill.com
burpnbill.live

Counter

#0142 · T7

4 items

Kitchen

Ready

04Craft

The parts nobody sees, done properly.

What I’ve built and run in production, and the tools I reach for.

Payments01

Payments, refunds and payouts

Integrated Cashfree end to end: checkout, signed webhooks, refunds and payouts, with idempotent handling so a retried callback never double-counts.

Integration02

ONDC network integration

Built the buyer-app flow for metro ticketing on ONDC: search, select, init, confirm and cancel, with request signing and callbacks handled in a dedicated service.

Reconciliation03

T+1 settlement and reconciliation

Designed the daily batch that settles collected fares to the metro operator and reconciles them against the network, safe to re-run and safe under concurrency.

Scale04

Rate limiting and API protection

A Redis token-bucket limiter with rules editable live from the admin, keyed per user or per OTP target so one shared network can't lock out everyone on it.

Platform05

GitLab, Jenkins, Docker, Azure

Moved source control to self-hosted GitLab, replaced GitHub Actions with Jenkins pipelines, containerised the services and ran the staging and production VMs.

Product06

Billing that stays exact

BurpnBill freezes lines, café details and tax into every bill. Money is numeric in Postgres and summed in SQL, never floats, so a reprint is always identical.

05Contact


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© 2026 Nilanjan Nath · Designed & built by me