Laravel Bulk CSV Processing: Preflight Checks, Holds and Retries for SIM Activations

A developer built a bulk SIM card activation feature in Laravel for a wireless dealer platform, where each CSV row triggers a paid wholesale activation through carrier APIs. The article argues that the difficult part is not chunking files and dispatching jobs, but deciding what is validated before any money moves, how funds are held, and what retries may repeat. The author favors an all-or-nothing preflight that checks each row against the carrier's own constraints, such as stock availability per ZIP code, so a bad file is rejected before any charge occurs. Funds are reserved in a single database transaction with a row lock on the wallet, which prevents concurrent uploads from overspending the same balance. The write-up describes these patterns in general terms because the client work is covered by an NDA.