About a year ago data streams team at Wix has released to open-source its Kafka client SDK wrapper called Greyhound. Greyhound offers rich functionality like message processing parallelisation and batching, various fault tolerant retry policies and much more. This talk will show how the team designed Greyhound with a layered architecture to allow both public and private parts and also different levels of flexible configuration. How it automatically syncs only relevant code from private repo to public one and also how it securely accepts public PRs back to the private repo. Outline: * Quick intro on what Greyhound is and its history at Wix * Greyhound layered architecture design to allow both public and private parts and also different levels of flexible configuration. * How it automatically syncs only relevant code from private repo to public one using Copybara tool * how it securely accepts public PRs back to the private repo.