[I work at Plaid] I don't know if we explicitly write down in the docs that the free Development tier isn't guaranteed to have the same SLA as the production environment, but if you're not paying Plaid there is no SLA (I mean, the usual recourse for an SLA breach is a rebate, but you can't give a rebate to someone who isn't paying you in the first place). That said, in practice the differences between the free and paid tiers for a personal finance app are not really such that someone doing a hobbyist app for personal use would notice them.