Abstract: In some aspects, the disclosure is directed to methods and systems for synchronized multi-client content delivery, and a content selection system based on individual and aggregated scores for the content items, to generate bundles or sets of content items having approximately corresponding scores. Server timers and local timers on client devices may be synchronized via notifications, and timer durations dynamically adjusted when client requests and responses are sent prior to client-side timer expiration, but received after server-side timer expiration, indicating communication latency has caused desynchronization. Timers may be adjusted on a global basis or per-client device basis. Through scoring and bundling, sets of content items that may be relevant to approximately an equal share of the recipient client devices may be selected and transmitted.