Jesvi Jonathan

I make apps that ship on time. I also make systems that stay up, websites that load fast, tools that earn their place, records that hold up and mixes that translate.

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CH 01Expertise Profile · 2 min read

Profile · Software engineering

The engineer behind the console

I'm Jesvi — a software developer from Chennai. I build the backend systems businesses run on, the web and app layer on top, and the AI tooling teams use every day. By day that's payment infrastructure moving real money in real time. The rest of the time it's my own software, and my own records.

01Experience

Associate Engineer

Tenure
3 years · 2023—present
Based
Chennai · Pune Onsite
Sector
Fintech · payments
C++PaymentsPCI-DSSISO 8583/20022GenAIHigh availability

Payments engineering on a high-availability C++ pre-processor handling millions of real-time transactions across multiple acquiring platforms. I build the payment protocols to PCI-DSS and ISO 8583/20022 under strict low-latency SLAs, ship features for the European and Australian platforms, and build GenAI-driven internal tools and test frameworks — one of which lifted developer productivity by around 40%.

02The short version

Most of what I do sits in the part nobody sees — the layer where a dropped message is somebody's money. Three years of payments work has left me with one instinct that shows up in everything else I build: assume it will be handed the worst input on the worst night, and design for that first.

None of it was a career pivot. I started making beats before I could afford an interface and started writing code because the tools I wanted did not exist, and both turned out to be the same habit — take the thing apart, work out why it works, build my own.

Anyone can demo. The engineering is in what still works at 3am, on a bad network, on the hundred-thousandth request.

03What I actually build

Backends and APIs, the interface on top of them, deployment, and the unglamorous parts in between — monitoring, auth, the migration nobody scoped. Increasingly that includes AI features that earn their place: retrieval over a company's own documents, an internal tool that deletes a manual step, a model doing work rather than appearing in a pitch deck.

I'm self-taught in most of it, which is a fact about how I learn rather than a gap. The degrees came after the projects, not before them.

04Credentials

05Skills & tooling

Languages C++ Python JavaScript Java Bash SQL Frontend Vue 3 Figma WebGL Responsive design UX / UI Backend REST APIs High-availability services Payments & protocols ISO 8583 / 20022 PCI-DSS AI & ML LLMs RAG systems GenAI tooling Machine learning Cloud / DevOps Google Cloud Docker Linux Git Grafana npm
CH 02Selected work 6 projects

Things I have shipped

Six things I built and still maintain, all of them public. The rack plays through them on its own — take a channel and it stops for you.

Product

1st Hackathon winner

Nullbyte Ticketing System

A ticketing platform that folds generative AI into triage and resolution, so a support agent opens a drafted answer instead of a blank box. It won the Google Cloud GenAI Hackathon it was built for.

Vue · Python · GenAI

View source

Open source

64,000 downloads a month

JOS Animation Library

A dependency-free scroll animation library that adds motion to every element on a page from one script tag. It is pulled from npm and cdnjs every day by people I have never met, on sites I will never see.

JavaScript · 65 stars · npm · cdnjs · MIT

View source

AI & data

Snitch-GPT

Detects AI-generated text. Scores a passage across GPT-class models and reports what it found and why, rather than returning a single unexplained verdict.

Python · NLP · GPT-class models

View source

Open source

Jesvi Bot

An all-in-one Telegram handler — utilities, media tools, cross-platform support, and a setup that takes minutes rather than an afternoon of config files.

Python · Telegram · cross-platform

View source

AI & data

Pro Scraper

Pulls product listings at scale and runs analysis over the result, so what comes out is a read on the market rather than a pile of rows.

Python · ML · data pipeline

View source

Web

Takshashila

A single-page framework built on top of my own animation library — the starting point I reach for when a site has to move without pulling in half of npm.

JavaScript · built on JOS

View source
CH 03Freelance Available for work

Software built for you

Beyond the day job I take on client work. Four kinds of it, and you are talking to the person who writes the code the whole way through.

01

Websites

Marketing, portfolio and product sites that load fast, read properly on a phone, and that you can update yourself.

  1. Design and build, end to end
  2. CMS or dashboard where you need one
  3. Performance, SEO and analytics
  4. Hosting and deploys set up for you
02

Applications

Full web and mobile products — usually the thing you have been running out of a spreadsheet, done properly.

  1. Web and mobile apps
  2. Auth, payments and admin panels
  3. Realtime features and integrations
  4. Docs and a clean handover
03

Backend & automation

The engine room: reliable services, clean APIs, and automation that deletes a manual step for good.

  1. REST APIs and services
  2. Integrations between systems you already run
  3. Data pipelines and scraping
  4. Monitoring, so you hear it from you first
04

AI features

LLM and RAG features that do real work — and the internal tooling that makes a team measurably faster.

  1. Retrieval over your own documents
  2. Chat, search and extraction
  3. GenAI internal tooling
  4. Added only where they earn their place

ScopeFixed price, agreed up front OngoingMonthly retainer available OwnershipCode and accounts are yours — no lock-in

CH 04Studio Chennai

One room,
two crafts

All of it is made in one room in Chennai — an analog front end into an in-the-box mix, on the same desk that ships the code.

There is no handoff here because there is nobody to hand off to. Whoever writes the part is whoever mixes it; whoever draws the page is whoever deploys it — one person who learned both halves and refuses to put either down.

The frames are the room itself: the desk, the signal chain and the screens that the records and the software actually come out of.

01
The room
02
The desk
03
The chain
Frames 01—03 Chennai
01Room
Hybrid — analog front end, mixed in the box
02Desk
Sessions and source on the same machine
03Since
2019, self-taught on both sides
CH 05Music 26 releases · 3.5M+ streams

Written, produced, mixed, mastered

The other craft, and a service. Tamil, pop and gospel with a lot of alt-rock and EDM in the wiring — every record start to finish in one room. Pull the crate along; the sleeves play.

Spotify Full catalogue Apple Music 26 releases YouTube Sessions & sets
Also on video @JesviJonathan

Here we go again

2026-07-04

Jail Time Music | FLP

2026-07-04

Zingan zao zao zao, zuh

2026-06-25
Subscribe on YouTube

Project files, jams and works in progress.
CH 06Process 4 stages

How it goes

The same four stages whether it is a record, a website or a piece of software. You see it as it goes, so nothing is a surprise at the end.

01

Talk

What is it for, who is it for, and what does done look like. Usually one call, and you get a fixed number at the end of it.

02

Sketch

A rough version, fast — a demo mix, or a clickable page. Real enough to react to before anyone commits to the long part.

03

Build

The long middle. Regular check-ins with something you can actually open, not a status update.

04

Ship

Delivered with the files, the access and the notes to keep it running after I have gone.

CH 07Contact Patch bay

Tell me about it

What it is, roughly when you need it, and a budget range if you have one. Everything here comes straight to me — no form, no assistant, no queue.

Available for work IST 00:00:00 Replies within a day

Email me
jesvi22j@gmail.com Email +91 70104 93945 WhatsApp +91 70104 93945 Phone in/jesvijonathan LinkedIn Résumé PDF, one page Download
Statement Three jobs, one desk
The software and the record, made by the same hands.
01

Producer

Writes it, arranges it, and plays whatever the song turns out to need.

02

Engineer

Mixes and masters it until it holds up on a phone, in a car, and in a club.

03

Developer

Designs and builds the thing it lives on, then keeps it running.