Synthorai
Sign up free, 10 calls on us. Up to $1, no card needed. DeepSeek V4.1 Flash - 65% OFF Input, output and cached input. Eligibility applies.

Billing & Top-up

Balance, top-ups, payment history and what each request cost. Usage draws down a prepaid balance - there is no monthly platform fee and no subscription.

In the console sidebar (it appears once the feature applies to your account): Billing Open it ↗

Steps

  1. Open Billing to see the current balance and what has been spent.
  2. Press Top up and choose an amount. Card and crypto are both accepted; the balance is credited once payment settles.
  3. Watch the balance land - a top-up is usable as soon as it appears, no waiting period.
  4. The Payments tab lists every top-up with its date, amount, credits and status.

Limits and gotchas

  • Free credit comes from a welcome campaign, not from signing up. Where one is running you can redeem it once per account; otherwise the first call needs a top-up.
  • Requests are billed as they complete. A provider error that produced no tokens is refunded; an error whose response still carried usage, or a stream you disconnect from partway, is charged for what was produced.
  • Cached prompt reads bill at a separate, lower rate - see the prompt caching guide for what that does to a bill.
  • Auto top-up adds credits when the balance runs low. On the Billing page, press Set up and enter three amounts: the balance that triggers it, how much to add, and a monthly limit. Then add a card on Stripe's page; adding it charges nothing. Each automatic charge is the amount plus the card processing fee, and comes with a Stripe invoice. If the card is declined, or a card payment is refunded or disputed, auto top-up pauses and the workspace's admins get an email. It is not tried again until someone turns it back on. Change card adds a new card, which is the one charged from then on.
  • Monthly budget is a ceiling the owner sets on what the workspace is charged in a calendar month (UTC). At the budget, requests are refused with 402 and the error type budget_exceeded until the month ends or the budget is raised. It counts credits, not calls on your own provider keys. It compares spend already recorded, so requests in flight can take the month slightly past it.

API reference for the same thing: Usage & Billing