Pay for what you use
Unslop is a small writing tool. Charges cover model calls, hosting and payment costs. Account creation and documentation cost nothing. Check live pricing and checkout availability before adding credits.
Prepaid billing starts when the owner enables it. Until then, the existing limited free allowance applies. Checkout is unavailable until Stripe and tax settings are connected. No card is charged by an API call.
Credits and charges
| Item | Price in USD |
|---|---|
| Credit purchase, before tax | $10 adds $9 credits; $25 adds $22.50; $50 adds $45. |
| POST, PUT or DELETE /v1 request | $0.005, excluding the billing routes. Includes deterministic analysis and gate-skipped rewrites. |
| Each attempted model call | $0.005 plus twice the token charge at the listed reference rates. |
| GET requests, quotes and checkout creation | No usage charge; rate limits still apply. |
The 10% retained from a credit purchase pays toward card fees, account storage and service overhead. Tax, if due, is added by checkout and does not become credits. Credits have no scheduled expiry, cannot be transferred, and do not trigger renewals. For unused-credit refunds, contact the service owner through Nathan's website. Payment-processing fees may not be recoverable; applicable consumer rights still apply.
A successful call uses the provider's reported input and output token counts, including billed reasoning tokens. Cached input receives no separate discount in this first price schedule. Each call rounds up to the next millionth of a dollar. Text is never sent to an unpriced model on a prepaid account.
| Model | Input / million tokens | Output / million tokens |
|---|---|---|
| GPT-6 Luna | $0.20 | $0.75 |
| Claude Sonnet 5 | $2.00 | $10.00 |
These are conservative reference rates dated September 24, 2026. Luna uses the higher published long-context rate. Unslop applies its 2× multiplier and call fee to both models. Direct provider access is required for prepaid usage. Jev, Gateway and external detectors remain unavailable to prepaid accounts until their costs have an approved schedule.
Example: one Sonnet call reporting 2,000 input and 100 output tokens costs $0.015 in credits. With the request fee, a one-call request costs $0.020. Four such calls cost $0.065 including the request fee. Your response and balance history show the actual charge.
Your spending limit
Each paid request supplies X-Max-Cost-USD, from $0.005 to $10, and an Idempotency-Key. Unslop holds the full budget first. Before each model call, it checks that the remaining budget covers a conservative input/output estimate. It returns unused funds when the request finishes. Parallel requests cannot spend the same credits.
Successful calls replace the estimate with a charge based on reported tokens. A failed or timed-out call may still cost the provider money. If usable token counts are missing, Unslop charges the reserved estimate for that attempted call. Rejected edits and unchanged results can still incur model charges. Validation failures before any model call cost nothing.
If the next call would exceed your cap, it is not sent. Earlier calls remain charged, and the API returns an error. Retrying an identical key retrieves the prior outcome; it does not run the job again. If the server stops before settlement, the budget stays held until the owner reconciles it. Report the request ID without private text or credentials.
Payment and text records
Stripe hosts checkout and handles card details. Unslop grants credits only after verifying a signed Stripe webhook and checking the payment with Stripe. Duplicate events do not grant extra credit. Refunds remove the corresponding credits; a negative balance or unresolved dispute blocks paid use.
To support retries, prepaid requests may cache their response body in private account storage. A response can contain your draft, excerpts or revision. Up to five responses are retained for up to one hour and removed on the next paid request after expiry, so idle accounts can retain them longer. Larger responses are not cached. Charge records, request hashes and financial records remain; submitted request bodies are not stored. Saved voice profiles keep the text you chose to save.
Deleting an account requires a zero balance and no pending holds. Payment records remain after deletion for reconciliation. Provider and hosting retention policies still apply.
Where these prices come from
OpenAI pricing, Anthropic pricing, Vercel Functions, Vercel Blob and Stripe fees inform the schedule. Card fees vary by country and card. Model costs and hosting rates can change, so the owner must review prices before changing models.
No usage price can guarantee recovery of a fixed monthly bill when nobody uses the API. The request fee, call margin and purchase allowance contribute to that bill. Daily usage caps limit exposure. Existing owner-managed keys are self-funded and bypass prepaid charging; their costs remain the owner's responsibility.