Nezzar Kefif

Full Stack Engineer (Freelance)

• Built Metrasign, a document-certification platform that anchors a tamper-proof fingerprint of each document on a private (Hyperledger Besu) blockchain, verifiable by anyone.
• Designed a multi-tenant architecture with per-organization roles (owner, admin, certifier, auditor) scoped per document type, and managed wallets (web3signer) so users certify without ever handling a private key.
• Developed and deployed custom smart contracts (Solidity, Foundry) integrated via Viem, with async queue processing so the UI never blocks on network latency.
• Shipped public verification (QR code or file re-upload, no account), a documented external API with scoped revocable keys, and GDPR + PART-IS (EASA, ISO 27001-aligned) compliance with no personal data on-chain.

Freelance & Builder Program

• Shipped production dapps on the Superfluid money-streaming protocol across Base and Ethereum.
• Built developer tooling and SDK integrations around real-time finance primitives.
• Owned features end to end — from Solidity contracts and subgraphs to React frontends and CI pipelines.

Full Stack Developer (Freelance)

• Built frontend features and wallet integrations for link-based crypto payments.
• Implemented token transfer and claim flows across multiple EVM chains.

Full Stack Developer

Developed a web3 marketplace bridging digital fashion brands and onchain assets.

Full Stack Developer

Built core web apps for privacy-preserving identity — ZK badge minting and attestation flows.

Full Stack Developer

Delivered web & mobile apps (React, React Native, Node) for enterprise clients in agile teams.

Full Stack Developer

Built interactive web experiences and immersive digital products.