The hourly and daily request limits for each tier, and what happens when you reach one.
Two complementary limits apply to reads: an hourly cap that bounds burst speed, and a daily cap that bounds total volume. Both must be satisfied, and whichever you reach first returns a 429. Search shares the read limits.
| Tier | Read / Search (hourly) | Read / Search (daily) | Write (hourly) |
|---|---|---|---|
| Free | 300/hr | 4,000/day | 150/hr |
| PRO | 1000/hr | 20,000/day | 500/hr |
| Developers Business | 10,000/hr | 100,000/day | None |
| Developers Scale | 100,000/hr | 1,000,000/day | None |
VerseDB Developers keys read the catalog and look up barcodes; every key of an organization draws on its one allowance. Cover photo lookups (POST /api/v1/lookup/cover) have their own limit instead: 5 a minute and 100 a day on Free, 15 a minute and 500 a day on PRO. All callers together share 30 a minute, so a 429 can arrive before your own limit; wait for Retry-After.
Exceeding either limit returns an HTTP 429 response with a Retry-After header telling you when to retry. The daily cap keeps the API responsive for everyone and prevents dataset mirroring (see Acceptable Use), so design integrations to cache and request only what they need rather than walking the full catalog. For handling strategies and best practices, see our API Support Articles.