Sequin offers an efficient solution for syncing data from HubSpot's API to local databases and systems like Kafka, overcoming challenges such as change detection and rate limits. HubSpot's API, a key tool for companies managing marketing and customer service, presents difficulties due to its lack of webhooks for custom objects, incomplete support for associations, and eventual consistency issues in its Search API. Sequin's sync process involves schema introspection, backfilling historical data, and ongoing change detection through strategic API querying, despite HubSpot's limitations in detecting deletes and managing associations. The system employs an in-memory cache to handle inefficiencies and potential data type issues, ensuring that changes are captured accurately even with the API's eventual consistency. By utilizing OAuth apps for dedicated rate limits, Sequin minimizes interference with other integrations, while maintaining real-time data propagation. The sync process abstracts API complexities, reduces latency, and increases data queryability, significantly enhancing operational efficiency for users.