← work

Blockchain and smart-contract development

Solidity contracts and blockchain applications, with work on Ethereum, Polygon and Hedera. I am based in Zaandam, near Amsterdam.

The contract is one part of the product

A blockchain application also needs an interface, permissions, transaction handling and a way to recover when a network request fails. I work on those pieces together. I do not take on work for proof-of-work chains.

Contracts for an Amsterdam art studio

For SUYE I built a platform that deploys an ERC-721 contract for a collection or certificate on Ethereum or Polygon. The artists do not have to buy crypto or operate a wallet themselves. The application manages deployment, metadata and the widgets embedded in their own websites.

One problem was a deployment that succeeded on the chain after the server request had timed out. Saving the transaction hash as soon as it was broadcast made it possible to recover the receipt and finish the record. The case study describes the checkpoints and the trade-offs.

A ledger inside a larger system

Kwantor connects equity agreements, signatures and software execution with tokens on Hedera. My work included the application architecture, interfaces and ledger integration. It is a different problem from an NFT collection: the agreement, the application’s permissions and the settlement must stay consistent.

Scope matters

I can help build the application and its contract integration. A development engagement is not an independent security audit. Before deciding what belongs on a chain, I want to understand what it needs to prove, who controls it and what happens when something goes wrong.

Technologies

• Solidity
• ERC-721
• ethers.js
• Ethereum
• Polygon
• Hedera

Selected work

• SUYE: digital certificates for physical art

  I built a platform that lets SUYE and its artists issue digital certificates (NFTs) for proof of originality, with JS widgets to integrate into their existing websites.

• Kwantor: turning participation agreements into software

  I led development of a platform connecting participation agreements, contributor work and equity allocation. The main challenge was keeping the document someone signs consistent with the rules the software executes.

• WEYU: NFT creator tool, launchpad & marketplace

  I worked on WEYU's platform in a team of about eight. There was a marketplace, a creator toolbox + launchpad and Discord bots. My job started with "WEYU pieces" which was a massive collaborative charity project in collaboration with UNHCR.

Working together

I work from Zaandam, next to Amsterdam, in the Netherlands. Tell me what you want to build, what already exists and where you are getting stuck.

Email me at m [at] hacktis.ch.