Read the monthly plan (null when none), the tiers on offer, the topped-up balance, whether a new plan can be started, the cheapest path for the recent spend and the last period's usage

The account's monthly plan and everything needed to offer one. subscription is null when the account never had a plan; a plan that has ended is still returned, with status: "canceled". tiers lists the tiers on offer with their priceHal and creditHal (hellers, excluding VAT). topupBalanceHal is the topped-up credit; GET /v1/balance carries the same two blocks next to the total. available says whether this account can start a NEW plan right now - an existing plan is always returned and keeps working when it is false. recommendation is the cheapest way to pay for what the account actually spent in the last 30 days (the same calculation as the calculator on the website): spendHal, cheapestPath (per_second or plan), the cheapest tier with top-ups tier and its cost tierTotalHal, the saving savingsHal, worthIt, whether the saving is big enough, steady, whether the spend is ongoing rather than a one-off peak (usage over the last 14 days scaled to 30 days, plus monthly number fees, reaches at least the price of the recommended tier; the portal offers the plan only when worthIt and steady are both true), and options, every way to pay for the same spend (per second and each tier with top-ups; the same figures the portal shows when changing the plan level). It is null when the plan is not offered to the account or the credit history does not reach 30 days back (a new account). previousPeriod summarizes the paid period before the current one (subscription.periodStart), with the same figures as the renewal e-mail: the tier, periodStart and periodEnd (ISO 8601), its monthly credit creditHal, how much of it was used usedHal and usedPercent (rounded down), spending beyond the monthly credit overHal (with top-ups without debt that the next credit paid off, with the cap including debt; null when the credit history cannot prove it), what expired expiredHal, exhaustionMode and exhaustedAt, when the monthly credit ran out (null when it did not, or when the credit history cannot show when). It is returned only while the plan is active, whatever available says; it is null without a plan, with status past_due or canceled, in the first period, when the credit history could not prove the usage, and 45 days after the renewal that saved it.