Joon
Software Engineer at cosmos tendermint
Berlin, Germany
Summary
🤩
RockstarJoon is a Berlin-based software engineer with a decade of experience building robust backend systems and a clear passion for functional programming. He’s an active open-source contributor to major blockchain projects like Tendermint and Cosmos SDK, focusing on low-level cryptography, Merkle proofs, and Inter-Blockchain Communication (IBC) logic for cross-chain asset transfers. His work shows deep familiarity with data serialization, hashing, packet sequencing, and the practical challenges of distributed ledger interoperability. Comfortable in Go and systems-level code, he combines meticulous refactoring with feature implementation to make complex protocols auditable and maintainable. Notably, Joon’s contributions bridge theoretical primitives and production-grade relayer components, reflecting both algorithmic rigor and product-minded engineering.
10 years of coding experience
Github Skills (13)
golang10
cosmos-sdk10
distributed-systems10
consensus10
go10
merkle-tree10
cryptography10
blockchain10
data-structure9
cryptocurrency9
data-structures9
tendermint9
bft-protocols8
Programming languages (8)
Github contributions (5)
cosmos/cosmos-sdk
Mar 2018 - Jan 2020
:chains: A Framework for Building High Value Public Blockchains :sparkles:
Role in this project:
Back-end Developer
Back-end DeveloperContributions:161 commits, 96 PRs, 791 pushes in 1 year 10 months
Contributions summary:Joon contributed to the implementation of Inter-Blockchain Communication (IBC) functionality within the Cosmos SDK, focusing on defining message types, handling logic, and building a relayer application. Their work included designing and implementing core components for transferring assets between blockchains, including packet handling and sequence management. The contributions are evident from the code diffs with specific modifications to the x/ibc directory. The code changes involve modifications to the handling logic of the ibc and the definition of the associated messages.
golangcosmos-sdkblockchainchainscryptocurrency
tendermint/tendermint
Apr 2018 - Jan 2019
⟁ Tendermint Core (BFT Consensus) in Go
Role in this project:Back-end Developer
Back-end DeveloperContributions:11 commits, 8 PRs, 5 pushes in 9 months
Contributions summary:Joon primarily contributed to the Tendermint Core codebase, focusing on low-level cryptographic and data structure implementations. Their work includes adding and modifying Merkle proof functionality within the `merkle` package. Additionally, the user refactored and exposed data structures such as `KVPair`. The contributions indicate an understanding of data serialization, hashing, and Merkle tree implementations within a blockchain context.
golangcryptographybftconsensusethereum
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