Avenash Kumar · New York, USA

Principal Engineer,Payments & Fraud Platforms

I design and run real-time fraud and payment systems that decide in under 200 milliseconds, and I build privacy-first tools that do their work entirely in your browser. This site is where I write about the engineering, share videos, and show the products.

NowUS Mobile · since 2021FocusFraud decisioning · PaymentsOpen toSelect roles, consulting, advisory
Avenash Kumar
<200ms decisions200+ risk signals, 98.6% accuracy
11+Years building high-scale distributed systems
200+Risk signals evaluated in every fraud decision
<200msDecision latency on the real-time fraud platform
98.6%Fraud detection accuracy after adaptive decisioning

Featured projects

Three products I designed, built, and run. Two are tools that never upload your files; the third is a small shop born in my daughter’s first year.

All projects →
Screenshot of json-utils.com home page
Developer toolsLive product

json-utils.com

A complete JSON workbench: formatters, validators, converters, schema tools, code generators, a graph view, a jq playground, and JSON-LD processing. Everything runs in the browser; nothing is uploaded.

52 tools0 uploads540 testsCloudflare edge
Next.jsTypeScriptCloudflare Workers
Screenshot of fixtdoc.com home page
PDF toolsLive product

fixtdoc.com

Merge, split, sign, redact, and read text off a scan, all in your browser. PDF work usually involves contracts, statements, and identity documents, so the files stay on your device.

16 tools0 uploads60+ OCR languagesWCAG 2.2 checks
Next.jsTypeScriptWebAssembly
Screenshot of cubcozycrafts.com home page
Small businessLive product

cubcozycrafts.com

The storefront for CubCozyCrafts, my Etsy shop selling instant-download printables for a baby's first year: nursery wall art, milestone cards, newborn care logs, and planners in a soft watercolor woodland style.

13 listingsInstant downloadPrint at homeMade by a new dad
EtsyDigital printablesProduct design

Latest writing

Notes on software engineering, programming languages, fraud and payments, and applied AI.

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Software Engineering7 min read

Traps and Tips - Test Driven Development

TDD is widely practiced in all sorts of industries with all sorts of different programming languages, sadly it is not the starting point of every team! It is one of the reasons that TDD hasn't become so effective.

TDDTestingSoftware Design
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Software Engineering7 min read

QUIC - Birth of New Protocol in Layer 4 Family

This article covers the key concepts about QUIC that every network engineer, developer, and cybersecurity professional should know. Some of the major topics covered, include, why a new transport protocol was needed, how QUIC is different from TCP, how QUIC securely and reliably transports data while sitting on top of UDP. After reading this you will know how to QUIC is different from existing layer 4 protocols.

QUICNetworkingTCPProtocols
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Software Engineering3 min read

Send E-mail - HTML Contact Form

In this blog post I have discussed how one can send E-mail (with attachments) via HTML Form without worrying about backend servers such as PHP, NodeJS, Flask, etc.

HTMLFormsFormSubmitEmail
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Latest videos

Talks and walkthroughs from my YouTube channel, on AI applications, Kubernetes, and the Java platform.

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AIYouTube

Building an AI Application with Java Spring Boot, Cloudflare Worker AI, and MongoDB | End 2 End LLM

AIYouTube

Access LLMs for Free: A Guide to Cloudflare's Services | Worker AI | AI Gateway

AIYouTube

Run LLMs Locally

Off the keyboard

Most of my career has been spent on systems that cannot afford to be slow or wrong. Away from the keyboard I am a new dad, which is how a fraud engineer ended up designing nursery wall art at 2 a.m. The full story is on the resume page.

My resume →
Avenash Kumar outdoors, smiling
Avenash Kumar seated at a cafe table with a coffee
Avenash Kumar standing outside a cafe, holding a coffee

Want to talk fraud platforms, or a role?

I read every message. The fastest route is email, and the contact page has the rest of my profiles.