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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

• Certificates of originality on Ethereum and Polygon for an art studio

  A platform where an art studio and its artists deploy an ERC-721 contract per collection or per certificate, without holding any crypto themselves, and drop the mint button, the certificate wall and the token gate into their own websites.

• Platform for universal programmable equity management

  A platform where the equity agreement is not a PDF describing the deal but the thing that runs it: signed once, then executed by software, with the tokens on a real ledger.

• Decentralized NFT launchpad and marketplace for WEYU

  The backend of a multi-chain NFT ecosystem, 2021 to 2022: an escrow marketplace with its own payouts and integrity checks, an indexer that read Magic Eden, and a Discord bot that gives roles to whoever is staking.

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.