Efficient, Secure, Bespoke NFT smart contracts & apps

CoffeeConverterHello!  My name is Aaron Hanson (AKA “Coffee Converter”).  I’ve been writing software for over 30 years.  By day, I’m the Staff Solidity Engineer at Nifty Gateway.  By night, I write NFT (and other) smart contracts and related apps.

My NFT contracts are customized and optimized for your exact needs.  They are highly gas-efficient, clearly documented, unit tested with 100% coverage, and fully-featured for token holders and contract admins.  I can also provide many related services (web apps, hosting, IPFS gateways, etc).

My Portfolio

Soundscape Avatars

The Soundscape Avatar NFT is a collection of gasless-customizable avatars by Cromagnus and SAN Sound.


In-ear-monitors designed by IMCMPLX and engineered by Beats by Dre’s founding engineer, David Leung.


The best-performing delta hedge on Arbitrum! Fully decentralized, no minimums or lockup periods.

Medicinal Mass Media

Official NFT of the Medicinal Mass Media Network, a network for the not-so-normal.

SAN Music Notes

Exclusive mint passes for the upcoming Soundscape Avatar NFT and SANWEAR™ (Hyper Reality Audio Headphones).


SAN Sound's weekly saga from Artist Cromagnus and Writer MintyFreshVibes, free to mint for SAN Origin holders.

SAN Origin | 三

A free-mint “soulbound” NFT collection powering a new listen-to-earn music streaming service.

Praise Gold Card

The limited-quantity Gold Card is like the ultimate master key to the Praise universe.

Supreme Skulls

A collection of 4,040 randomly generated, animated 3D skeleton NFTs on the Ethereum blockchain.

The Gambit Club

A collection of 3,200 chess-themed NFTs featuring the art of Tom Fry.


A two-way NFT bridge between Ethereum and Bitcoin via Stacks.  Bridge some Satoshibles over today!

KAINET Staking

A fixed-APR staking contract for the KAINET token.  Land of Kai is a 3D open world play-to-earn game.

Built With NFT

100% charity project.  10,000 unique NFTs, hand drawn by students from Built With Bitcoin schools across Africa.


Every NFT holder gets a copy of the physical fine art monograph by Devin P. Marty.

Monster Satoshibles

6,666 monster NFTs that can be burned and combined in “The Lab” to mint rare “prime” monsters!