Junkil Park
Software Engineer at Waymo
Mountain View, California, United States
Summary
🤩
Rockstar🎓
Top SchoolJunkil Park is a software engineer with 11 years of experience specializing in back-end development, formal verification, and test automation, currently based in Mountain View and working at Waymo. He has deep expertise in the Move language and Move Prover from significant contributions to high-profile blockchain projects like Aptos and Diem, where he improved prover reliability, fixed subtle specification bugs, and modernized verification tooling. Prior roles at Meta and research positions reflect a strong research-to-production trajectory—he combines PhD-level training with pragmatic engineering to ship robust verification and CI solutions. Notably, he has hands-on DevOps experience upgrading SMT toolchains (Z3/Boogie) and tuning CI to handle timeouts, an often-overlooked but critical part of keeping verification workflows practical.
11 years of coding experience
6 years of employment as a software developer
Integrated Master and PhD Course Computer Science, Integrated Master and PhD Course Computer Science at Korea UniversityDoctor of Philosophy - PhD Computer Science, Doctor of Philosophy - PhD Computer Science at University of Pennsylvania
Github Skills (22)
spec10
verification10
boogie10
verify10
lang10
formal-verification10
specification10
z310
move10
movelang10
test-automation10
cicd9
cd9
blockchain9
build-automation9
Programming languages (11)
Github contributions (5)
aptos-labs/aptos-core
Jul 2022 - Jan 2023
Aptos is a layer 1 blockchain built to support the widespread use of blockchain through better technology and user experience.
Role in this project:
Back-end Developer
Back-end DeveloperContributions:757 reviews, 43 commits, 357 PRs in 5 months
Contributions summary:Junkil's commits focused on enhancing the Move Prover's capabilities within the Aptos ecosystem. They addressed test failures by modifying the `translator_tests.rs` file to add test flags and by adding more tests to vector verification files. They also improved the prover by replacing the recursive power functions with iterative ones. The user also added a custom boogie file and also fixed a bug in the specification of `bit_vector::unset` to ensure correct functionality of the prover. They also implemented the spec pragmas "emits_is_partial" and "emits_is_strict".
blockchainblockchain-networksmart-contractsaptos
diem/diem
Jan 2020 - Mar 2022
Diem’s mission is to build a trusted and innovative financial network that empowers people and businesses around the world.
Role in this project:Back-end Developer & Test Automation Engineer
Back-end Developer & Test Automation EngineerContributions:155 reviews, 116 commits, 174 PRs in 2 years 1 month
Contributions summary:Junkil primarily worked on the Move Prover, focusing on specifying and verifying aspects of the Move language. They fixed issues related to the "emits" clause in specifications, corrected specifications for several modules like LibraAccount and FixedPoint32, and added tests to improve code coverage. The user contributed to the implementation of automatic inconsistency checking, which aids in identifying potential errors. They also worked on improving the testing framework by introducing new test cases and correcting existing ones.
diemfinancialtrustedethereumblockchain
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