Billing and credits
Silk Compute is prepaid. You add credits, and each request is charged per token at the model's rates. There is no subscription.
Add credits
Top up from $5 on the Top up page, by card (including Apple Pay and Google Pay) or by crypto: Monero, Bitcoin, Ether, USDT, or USDC. Card payments are credited immediately; crypto after the network confirms the transfer.
What a request costs
Input, cached input, and output tokens each have a price per 1M tokens, listed on the models page. Input the model reads from its prompt cache is charged at the cached rate, so keeping the start of your prompts the same (system prompt, tool definitions, earlier turns) lowers the cost of long conversations.
Auto top-up
After a card payment you can turn on auto top-up: when your balance drops below a threshold you choose, the card is charged a set amount.
Running out
When your balance is too low, requests return 402 insufficient_credits. The Usage page shows spend, tokens, and requests per model and per API key.