Credits & quotas

Charging policy

Outcome	Charge
`succeeded`	Full reservation (1 credit/job)
`failed` / `timed_out`	0 — reservation released
`cancelled`	0 — reservation released

Ledger

Every balance movement is a CreditLedgerEntry: grant, reservation, consumption, release, refund, adjustment. Entries are write-once — corrections are new entries, never edits. Inspect yours at GET /api/v1/credits/ledger.

Quotas

Each plan defines data-driven limits enforced on the backend:

monthlyCredits — allotment granted each billing period
maxConcurrentJobs — simultaneous queued+processing jobs
requestsPerMinute — job submissions per minute
maxJobDurationMs — per-job timeout ceiling
allowedOperations — enabled challenge categories

Exceeding a quota returns 429 quota_exceeded or rate_limited — never a silent drop. Insufficient balance returns 402 insufficient_credits.