Credits and limits
How usage is metered in credits, what a document may contain, and the per-key rate limits with what the API answers at each edge.
Credits
Every check draws credits from the account's balance: 150 credits per 250 words, so 1,000 words cost 600 credits. The credits are reserved when the check is accepted and settled when it finishes. A check that is rejected, fails or is cancelled releases its reservation and charges nothing.
- Meter
- 150 credits per 250 words
- Starter credits
- 1,500 with your first key
- Pack credits
- Never expire
- Same balance as
- Your Silvertext plan
Read the balance at any time with GET /v1/me/usage:
curl https://api.silvertext.com/v1/me/usage \
-H "Authorization: Bearer $SILVERTEXT_API_KEY"balanceAvailableCredits is what a new check can draw on; balanceHeldCredits is reserved by checks in flight; log lists recent spend. Buy packs under Account, then Subscription in the app; the API page lists the packs and their per-1,000-word price.
What a document may contain
- Words per check
- Up to 25,000
- Upload size
- Up to 25 MB
- Formats
- .txt .md .html .csv .docx .xlsx .pdf, images by OCR
- Languages
- English, Spanish, French, German, Portuguese, Italian, Dutch, and source code
Text is decoded from UTF-8, UTF-16 or Windows-1252. Files are judged by their bytes, never by their extension or declared type. Scripts written without spaces between words (Chinese, Japanese, Thai) are refused at submission with unsupported_language. Every one of these limits is judged before the check is accepted, so a 202 means the document was read and will run.
Rate limits
Limits apply per key and are sized for integrations that submit in bursts.
- Requests
- 120 per minute, every route counted
- Check starts
- 300 per hour
- Checks in flight
- 5 at once per account
- Live keys
- 5 per account
| Limit hit | Status | Code | What to do |
|---|---|---|---|
| Requests per minute | 429 | rate_limited | Wait for the seconds in Retry-After, then retry. |
| Check starts per hour | 429 | rate_limited | Same: Retry-After says when the window opens. |
| Checks in flight | 409 | concurrent_limit | Poll an in-flight check to completion, or cancel one, then resubmit. |
| Credits | 402 | quota_exceeded | Buy a pack; the message says how many credits the check needed. |
Rate limits and backoff has a retry recipe that handles all four.