Chess.com moved analytics for a product with more than 300 million users from an external platform to one it controls. I led the migration across nearly one petabyte and 79 production models, reconciled identity across 2.5 years of history, and kept realtime consumers live through cutover. No events were lost.
Figures describe the migration and specific engineering reference windows. They are not current public company KPIs.
Acquisition, experiments and product metrics all depend on consistent identity. The migration therefore included session reconciliation, signup anchors, passive traffic rules and cutover validation. The work was tested against defined engineering windows before consumers moved.
I designed and delivered the migration to governed events on Chess.com's own platform: a unified event contract spanning event generations, source reconciliation with cutover validation, and rollback protection for every downstream consumer. Chess.com now owns its identity and event data end to end. There is no usage based vendor pricing and no external dependency in the critical path.
Identity was reconstructed deterministically across 2.5 years of history. Healed session IDs, registration events as signup anchors, and sessions shared by multiple users untangled rather than thrown away. Passive server activity is separated from active use under governed rules. Audit columns explain every correction on the data itself.
The migration split unified events into raw, healing and final layers, so downstream models moved over gradually and safely. Realtime consumers kept running against the same contract while 79 production models were realigned underneath them. The validation suite passed before each cutover stage, and no events were lost.
An earlier proposal for a new service level person ID was explored and deliberately dropped after architecture review. Solving identity in a healing layer, with the raw data preserved, delivered the same analytical outcome at far lower risk. Knowing what not to build is part of the job.