Users · Data · Markets

Juan John Mathews

Seeking value at the intersection of users, data, and markets.

Eight years nurturing B2C products across ad-tech, e-commerce, and fintech — from zero-to-one launches to scaling revenue verticals through data-driven experimentation. I came up as a software engineer, so I still like to stay close to the data, the experiments, and the systems underneath.

Impact Ruminations Get in touch

Selected work

Loaders and Annals

Self-Goals

Quant & algorithmic market research

Standing up my own market-research desk — quantitative and algorithmic analysis of markets, with live studies running today and a deeper research roadmap planned.

quants.mathangya.art ↗

A lab with the lights always on

A live JupyterLab where the notebooks run hot — data wrangled, models prodded, and hypotheses poked until they confess. The workbench behind everything above.

Open the Lab ↗

Frontiers

Behavioural anti-spam on intent embeddings

Built and manage an anti-spam system that weeds out users with malformed intent through behavioural signals, while measuring strength of intent for genuine user interests — researching how user interests embed in vector space and cluster into behavioural affinities, and how deviations signal intent.

Media.net · Senior Product Manager

Personalised offer ranking at scale

Own the ranking stack that pairs each user’s intent with the advertiser offer most worth showing. Deterministic mathematical rails set the structure; revenue-driving offer parameters are tuned per user and scored through an ensemble of heuristics and ML models.

Media.net · Senior Product Manager

Done

Payments infrastructure for GCC expansion

Built and modernized payment infrastructure for the Dubai & KSA expansion — integrating payment gateways and wallets, Apple Pay, and security and reliability features like 3DS authentication and acquirer response-code handling. Over 12% lift in payment conversion.

MakeMyTrip · Associate Product Manager

$1.35M+ in engineering cost savings

As an engineer: an ML similarity engine for critical incidents (60% MTTR reduction), a blockchain asset ledger, and data pipelines scaling to 1 TB/day.

Fidelity Investments · Software Engineer

Also: ad-ranking products, refund automation, anomaly detection across 40+ metrics, NLP-powered ad classification. — full history on LinkedIn.

Ruminations

Notes at the edge of my curiosities

Essays-in-progress where obsessions overlap — markets, machines, minds, and the futures entangled. Symbiotes hum, machines whir, minds cluster, horizons approach.

Markets as machines — what programmatic finance and quant systems get right about the world. Quant
Trust without intermediaries — where blockchains actually remove friction, and where they just move it. Blockchain
The probabilistic universe — quantum intuitions for people who think in code and odds. Quantum
How groups decide — political science and incentive design read as systems problems. Polisci
The mind as an API — psychology, bias, and the user research it quietly powers. Psychology
Futures worth wanting — science fiction as a foresight tool for product and society. Sci-fi

Connect

Let’s talk

✉ Email in LinkedIn </> GitHub × X

Based in Mumbai, India

gen 0

// idea generator

Spark

For when the brain needs a jump start. One press throws out a half-baked prompt from one of my favorite rabbit holes.

> press spark to begin_

// off the bench

Orbital Atlas

Every tracked satellite — all 19,698 of them — parked in a browser and propagated live. Each object is one vertex carrying its orbital elements, so the GPU re-integrates every orbit from scratch, every frame. Spin the Earth, scrub time, click any dot and watch its orbit draw itself.

open it in your browser

orbital-atlas

19,698 tracked objects
1 km vs reference SGP4
3 MB, no dependencies

Search by name or NORAD ID, filter by orbit, follow the ISS around, or point it at your own rooftop and see what’s overhead right now — then unroll the globe onto an equal-area world map, where every country and every footprint is drawn at its true share of the planet.

orbital mechanics · webgl2 · map projections · celestrak elements

// off the bench

City Slabs

Three cities cut out of the map and stood on a plinth. Every building is a real OpenStreetMap footprint extruded to its real height, the coastline is stitched from raw coastline ways back into actual land, and a realism pass lights it like a photographed architectural model — sun on a slider, or flip it back to a clean map.

open it in your browser

city-slabs

566,000 buildings drawn
of 5 million surveyed
0 dependencies

Mumbai from Colaba to Borivali, all five boroughs of New York, Greater London along the Thames, Dubai from the Palm to the Burj Khalifa, San Francisco Bay and the Los Angeles basin. A yardstick of fixed real length lies on the table beside each one, so the cities can be compared against each other and not just admired one at a time. Turn the slab, push the sun around and watch every shadow swing with it — they’re the same prisms drawn a second time, flattened onto the ground along the sun ray. Save the view as a poster when it looks right.

webgl2 · openstreetmap · computational geometry · offline baking

// off the bench

Angels

Four angels standing together in one dark room, carved in code. There is no model file: each figure is a signed distance field, polygonised in the browser the moment the page opens, all four at once in parallel workers. Three are the winged humans of later art. The fourth is the one Ezekiel actually describes, and it looks nothing like them.

open it in your browser

angels

4 figures
1,938 feathers
373 eyes

A guardian with wings half raised, a herald with them spread, a mourner with them folded — and at the end of the arc a cherub of Ezekiel: four faces, of a man, a lion, an ox and an eagle; four wings, two stretched upward and two covering the body; straight legs ending in a calf’s hoof, burnished like bronze; the whole of it full of eyes, and a wheel within a wheel standing beside it. Click any one of them to step in, push the light round and watch the stone go translucent where it thins, because the same shadow map that decides what is lit also measures how far the light travelled through the marble.

signed distance fields · webgl2 · surface nets · instancing

open it in your browser

angels/metatron

72 wings
365 eyes, each a sun
49 stones

A fifth, on a page of his own: Metatron, the Prince of the Presence, as 3 Enoch tells it. A man whose flesh is changed into flames, his sinews into flaming fire and his bones into coals of juniper, raised and enlarged until he is the size of the world with the Earth beside him, then given seventy-two wings, three hundred and sixty-five eyes each as the sun, a garment of every kind of light and a crown of forty-nine stones like the sun, with the letters of creation written round it by a flaming style. Nothing is carved: it is all light, every flame and coal the colour of a body at its temperature.

gpu particles · blackbody colour · dielectric breakdown · diffraction

// on the bench

Half-built things

runs on my machine

vibe-backtester

A trading sandbox that began by trading on pure superstition, then slowly learned to respect the data. Mostly an excuse to feel market microstructure in my hands.

quant · programmatic finance

held together with tape

500-line chain

A toy blockchain from scratch — blocks, hashes, a grumpy little consensus rule — built just to feel what “trustless” actually costs.

blockchain

weekend idea

qoin

A quantum coin that refuses to be heads or tails until you look — then argues about whether it was ever really undecided.

quantum

held together with tape

rumor-mill

An agent sandbox where simulated people spread (mis)information through a crowd. Equal parts network theory, political science, and mild dread.

poli-sci · psychology

weekend idea

starfield.seed

A generative night sky seeded by my favorite sci-fi worlds — every constellation a what-if I’d happily live inside for a chapter.

science fiction

runs on my machine

bias.log

A growing field guide to the ways my own head fools me — with a changelog. Cataloguing cognitive bugs is the most honest debugging I do.

psychology

// the idea pile

Notes stuck to the wall

What does a market feel like from the inside?

Is a DAO just a city-state with better APIs?

Could you teach probability with a pair of quantum dice?

Which sci-fi futures are we accidentally building right now?

What if your biases shipped with a changelog?

Do crowds actually think — or just average?

// closing time

Built in the garage, mostly at night. Want to tinker on something together? Head back to the front, or knock on the door.