I'm João, a senior backend engineer (6+ years in Go) who spends the rest of his time on zero-knowledge cryptography and on-chain code. The day job pays the bills; ZK circuits and smart contracts on Ethereum and Solana are the part I actually care about.

Highlights:

• A ZK dark pool DEX (halo2 + arkworks) and a Solana compliance layer that runs Groth16 verification inside a Token-2022 transfer hook under 200k compute units.
• 36 merged PRs across Rust open source: 30 in Zed, 5 in the Rust compiler, 1 in Sway.
• Web3 mentor at Borderless Coding: 60+ engineers, 20+ live workshops.

DarkPool-Exchange, a ZK dark pool DEX. Orders stay private until settlement. The engine matches them in batch auctions every 5 seconds with one clearing price per round, which kills most front-running and MEV. I work on the Rust and Web3 side: halo2 and arkworks circuits, WASM and native proof generation, the proof aggregator, and the Solidity verifier integration.

zksettle, a Solana compliance layer for stablecoin fintechs. Proves travel-rule and sanctions conformance without putting any PII on-chain. A Token-2022 Transfer Hook verifies Groth16 proofs in under 200k compute units. Off-chain side is a Rust workspace: issuer service, OFAC sanctions updater with a Sparse Merkle Tree, Helius-webhook indexer that pins attestations to Arweave, and an axum API gateway.

• Crypto-Tip (35 stars): decentralized tipping platform. Solidity contracts on Ethereum plus a Solana program in Rust, integrated with MetaMask and Phantom.
• Pattpay (26 stars, Cypherpunk Hackathon): Solana payment gateway for one-time and recurring subscriptions. Anchor programs use a delegate-authority PDA to charge subscribers automatically. Supports SPL Token and Token-2022.
• givemoney.fun (backend · contracts): crypto donation platform for Twitch and Kick streamers. Solidity StreamerDonations contract on Ethereum (Foundry + OpenZeppelin) and an Anchor program on Solana for SOL and SPL Token-2022 donations.
• Proof Of Learn (NearX and ZKVerify Hackathon): AI-generated learning roadmaps validated by Circom ZK circuits, with on-chain NFT credentials issued via Solidity smart contracts (Foundry).

Web3 Technical Mentor and Ambassador at Borderless Coding (USA). Mentored 60+ engineers on Solidity smart contracts and blockchain architecture, ran 20+ live workshops with Foundry, Hardhat, and Remix, and helped grow the technical community by 200%.

Zed (Rust, 70k+ stars): 56 PRs submitted, 30 merged across 15+ subsystems, around 6,800 lines. A few I'm proud of:

• #51035: found and fixed a macOS deadlock in the GPUI rendering framework. Re-entrant key status changes were freezing the UI.
• #50705: reworked picker selection logic across 11 files so non-selectable entries can no longer confirm unintended actions in the command palette.
• #51623: SVG renderer was failing to render text when system fonts were unavailable.
• #53712: semantic tokens weren't appearing when opening a buffer from a multibuffer.

Plus 5 merged PRs on the OCaml extension (Dune support, MLX files, LSP argument forwarding, project root detection). All my Zed PRs.

Rust compiler (Rust, 103k+ stars): 12 PRs submitted, 5 merged across diagnostics, type checking, traits, rustdoc, and bootstrap.

• #157223: fixed a rustdoc ICE on delegated async functions.
• #156861: suppressed garbled strict-provenance lint suggestions inside macros.

All my rustc PRs.

Sway (Rust, 61k+ stars): the smart-contract language for the Fuel blockchain. 7 PRs submitted, 1 merged.

• #7629: optimized away zero-length MCP/MCPI instructions in the compiler backend.

All my Sway PRs.

Web3: Solidity, Rust (Solana / Anchor), Foundry, Hardhat, Remix, Token-2022, PDAs, ERC-20

ZK: halo2, arkworks, Groth16 (BN254), Circom, Noir, WASM proof generation, Sparse Merkle Trees

Languages: Rust, Go, TypeScript, Solidity, Java, Python, SQL, Bash

Backend (day-job stack): Go, Spring Boot, NestJS, REST, gRPC, GraphQL, microservices, Kafka, PostgreSQL, MongoDB, Redis

Infra: Docker, Kubernetes, ArgoCD, Datadog, AWS, OCI

Six years of senior backend work, mostly in Go. A few things from that side:

• Fixed a concurrency bug in an invoicing pipeline that processes 140M+ transactions a month.
• Cut PostgreSQL query times by up to 85% on the heaviest aggregations.
• Saved roughly $10k by migrating an invoicing stack from Java/Oracle to Go/PostgreSQL.

The full backend history lives on my LinkedIn.

• Brazil (UTC-3), remote, comfortable with US and EU overlap
• Email: blsoaresdev@gmail.com
• LinkedIn: linkedin.com/in/blsoaresdev