Kaichao Sun

MarkdownSync is a local-first markdown editor with real-time collaboration.

Docs live on your device first. Edit offline, edit on a plane, edit in a tunnel — when you come back online, everything syncs. Share a document and co-authors see each keystroke within a frame.

An Egwalker CRDT handles character-level merges. Every op carries a stable ID and causal dependencies, so concurrent edits converge without a central arbiter.

Movedone is a local-first Kanban where humans and AI agents work together seamlessly.

It’s beautiful, runs completely locally, and is blazing fast compared to any other Kanban or project management tool out there.

Technology stack includes CRDT, Rust, Tauri, React, Postgres, Sqlite etc.

To solve the pain point of crypto self-custodian, I started the project named Keyring, it’s building a secure and handy hardware wallet for Web3 citizens. More information on keyring.so.

Technology stack includes Javacard for smart card development, Go Wails for desktop app, React Native for mobile app.

It supports EVM compatible blockchains includes Ethereum, Optimism and Base. I successfully got support from Optimism RetroPGF, check out the proposal.

Work on Waku which is a decentralized, privacy-preserving communication network.

I contributed to the implementation of Go-Waku, focusing on core networking and messaging components. My work includes integrating the Double Ratchet algorithm for end-to-end encrypted private messaging within a Chat SDK, as well as implementing Reed–Solomon erasure coding to improve data reliability and resilience in peer-to-peer environments.

In addition, I implemented the Noise Protocol framework in Nim, enabling secure handshake patterns and encrypted transport layers. My research contributions span protocol reliability, bandwidth optimization strategies for resource-constrained networks, and exploration of Messaging Layer Security (MLS).

Work with Substrate, a Rust based blockchain framework. I designed a way for permissioned network to only connect with authorized nodes. Maintains a Proof of Stake blockchain template which follows mainnet launch process, includes consensus, staking, governance related pallets. Maintains the playground for easily onboarding developers, it covers the knowledge includes macro syntax used in FRAME, storage data types, genesis config, off-chain worker, etc.

Besides coding, I also actively promote Substrate to developers includes, writing deep-dive tech post around libp2p, Merkle Patricia Trie, goverance and decentralization, etc; produce the Substrate online course with more than 1,000 devs joined; support ecosystem teams with Web3 Bootcamp, hackthons, and Substrate Builder Program.

As a Full Stack Developer, I have been working for REA Group (a global online real estate advertising platform) for more than two years. During this period, I work closely with a great team (includes PM, BA, etc) to deliver many products like Audience Maximiser, Flexi subscriptions, etc. These products bring lots of value to the customers. Also participated a few HackDay projects, these projects are mainly focus on re-imagine business model and improve our daily workflow.

My work includes, architect design like microservices and its interaction based on domain knowledge, product requirement and organization structure. Leveraging functional programming to develop backend services reliably. Using React, Vue to create the web apps; Scala, Ruby, Java, Golang, NodeJS for backend; CI/CD with Docker, Buildkite, Bamboo. Familiar with the widely used infrastructure like AWS, k8s, Splunk, NewRelic, PagerDuty, JIRA, Git. Sharing knowledge in community, mentor others and recuriting.

I start my career in Quyi which is a startup building a health management App, it can also connect with traditional medical institutions like hospitals. I feel so excited to build a Web product, almost everything is different and new to me. As a quick learner, it talks me a few weeks to learn Java, understand the business.

Detail work includes: break the original monolithic architecture into microservices, coding the open platform with SpringMVC and RESTful interface for third-party application to access the services, develop service register and discovery with Zookeeper, design API Gateway with Netty, carry performance test with JMeter, provide technical support for third-party, etc.

I got to know Bitcoin in 2013, tried mining but network is blocking me to download any blocks. Wrote Solidity in 2016 with Remix, the dev experience is not good in the old days.

Since then, I started to exploring decentralized tech knowledge, it feels like home in this space, blockchain has its limitations, but more great things will coming!