Open Library
Education · 2 endpoints
The Internet Archive's open catalog of the world's books — search it by title, then read any work's full edition list: publishers, dates, formats, and ISBNs.
Base URL
Endpoints
Errors
401 Unauthorized
v1
{
"error": {
"code": "UNAUTHORIZED",
"message": "The API key is invalid, expired, or revoked."
},
"meta": {
"request_id": "req_7Q2fK4mZ"
}
}Every failure carries a stable machine-readable code before the human message, and the same meta.request_id the successful responses carry. Quote it and we can find your exact request.
Errors are free
Nothing on this page is billed. You are charged for a 2xx and nothing else — a rejected key, a bad parameter, a rate limit, or an outage on our side all cost you zero. Retry without watching the meter.
- UNAUTHORIZEDHTTP 401
- Missing, malformed, expired, or revoked API key.
- FORBIDDENHTTP 403
- The key is valid but lacks the scope this product needs.
- VALIDATION_ERRORHTTP 422
- A query parameter is the wrong type or out of range.
- RATE_LIMITEDHTTP 429
- Rate limit exhausted. `Retry-After` says how long to wait.
- SERVICE_UNAVAILABLEHTTP 503
- No data recent enough to serve. Carries `Retry-After`, and is never billed.
- Status
- Operational
- Category
- Education
- Rate limit
- 120 requests / 60s per key
- Pricing
- 1 credit / request
- Open Library Search
- Open Library Book
2/2 passing
Every response is timestamped. as_of is when the data was published, age_seconds how old that is now, and next_update_at when newer data is expected.
Three shapes to handle:
- Up to date200
The data is inside its published window. The overwhelming majority of requests.
- Delayeddelayed: true
Newer data is late. You still get the most recent there is, flagged so you can decide whether to use it.
- Unavailable503
Nothing recent enough to serve. Carries Retry-After, and is never billed.