Parity Technologies
Rebuilt XCM messaging test systems and end-to-end parachain testing in the polkadot-sdk, and shipped Minimal Relay, migrating state and functionality off the relay chain and onto dedicated system parachains.
Inside the polkadot-sdk
Working in Rust inside the polkadot-sdk repository, I rebuilt the parachain integration test systems for XCM messaging (the protocol parachains use to pass messages, including assets and calls, to each other and to the relay chain) and the end-to-end parachain testing systems that exercise that path. I also worked on FRAME pallet code, the modular Rust components that make up the actual runtime logic of substrate-based parachains, as opposed to the consensus and networking layer beneath them.
Minimal Relay
My main project was Minimal Relay: building out new System Parachains and migrating state, data, and functionality away from the relay chain and onto them. The relay chain's job is to provide shared security and coordinate consensus across parachains: the less general-purpose logic it has to carry directly, the less surface area there is for that shared layer to get wrong.
Because a migration like that can't be validated by inspection (you're moving live state, not just code), I built comprehensive tests using the XCM emulator to exercise the chain-state migrations themselves, not just the steady-state behaviour on either side of them.
The relay chain's whole value proposition is the shared security every parachain depends on, so the commercial value of Minimal Relay isn't a number on a dashboard, it's a category of incident that didn't happen. Getting a live state migration wrong on shared infrastructure doesn't produce a bug ticket, it produces a chain split or funds parachains can't recover. Migrating that logic off the relay chain, with XCM emulator coverage for the migration itself, is what let System Parachains carry more without the relay chain's own surface area growing to match.