Reddit's migration from a legacy Python service to modern Go microservices focused on their comment backend infrastructure. The previous system faced reliability and performance issues, prompting the decision to move to Go. Comments, being the most active model with the highest write throughput, were prioritized for this migration. This transition aimed not only to improve performance but also to ensure that user experience remained unaffected. The migration process involved careful handling of read and write endpoints. For reads, they employed a method called tap compare, which allowed them to compare responses from both the old and new endpoints without impacting users. Write migrations, however, posed greater risks due to the complexities of data storage and change event guarantees. To mitigate these risks, Reddit created "sister datastores" specifically for testing. These stores received writes from the new Go microservices while preserving the integrity of the production data. After migrating three write endpoints across three different datastores, the team successfully verified the data consistency between the legacy and new systems through extensive tap comparisons. This approach proved effective, resulting in a seamless transition with no disruptions for users. Notably, the migration reduced latency for write operations by 50%, showcasing the efficiency gains from the new infrastructure. The team also identified challenges unique to transitioning between programming languages, particularly in how they interact with databases.