Per-owner budgets

Useful when a single quota is shared across servers or accounts and you want each owner tracked separately (e.g. per outbound IP). by() scopes every window the limit enforces, compound ones included:

$middleware = RateLimits::perHour(60)->by('203.0.113.10');

Http::withMiddleware($middleware)->get('https://api.example.com/orders');

The macro takes the same owner as a named argument — Http::rateLimit(30, by: 'acct-1') — and it works with every form: an integer, a profile name, a RateLimit, a Limit or a compound array, where it scopes every window. It re-keys a copy, so a RateLimit or Limit you pass in (and reuse elsewhere) keeps its own key.

Keep upstream APIs apart

Hits are stored per owner key and window. A limit without by() uses the key global, and every limit records into one shared store, so two unrelated limits without a key on the same window read the same hit history. Give each API — and each tenant, when budgets are per customer — its own key:

// Without by(), every limit uses the owner key 'global'. Every limit shares one
// store, so give each upstream API its own key so their budgets never mix:
$github = RateLimits::perSecond(5)->by('github');
$stripe = RateLimits::perSecond(25)->by('stripe');

// Per-tenant budgets for the same API:
Http::rateLimit(RateLimits::perMinute(100)->by("billing:{$tenant->id}"))
    ->post('https://api.example.com/invoices', $payload);