We're migrating off our current product analytics vendor — what should we check about historical data export and event schema portability before we switch?

“For example, Amplitude's Export API returns compressed JSON event files, but has date-range, file-size, and rate-limit constraints.”

“Amplitude, for example, supports CSV import/export of tracking-plan events and properties, but its documentation identifies limitations around custom events and transformations.”

“For example, Amplitude's Export API returns compressed JSON event files, but has date-range, file-size, and rate-limit constraints.”

“It also uses server upload time rather than original event time to select export windows.”

“Amplitude, for example, supports CSV import/export of tracking-plan events and properties, but its documentation identifies limitations around custom events and transformations.”

“For example, PostHog's migration documentation describes using a historical_migration option when importing past events.”