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Service Constraints

Rate Limits

To ensure high availability and fair service quality, PDFKong enforces dynamic rate limits on all public API endpoints based on your subscription tier and request complexity.

Dynamic Traffic Isolation

API conversions are constrained by both type-specific rates (Sync vs Async, HTML vs Office) and a combined Global Convert Cap per minute, alongside hourly limits for batch files generation.

Limits by Subscription Tier

Subscription Tier Sync HTML/URL Sync Office Async HTML/URL Async Office Global Cap Hourly Batch Files

Quota & Limit Headers

Every successful API response includes custom headers to monitor your request limits and wallet credits balance programmatically:

Header Key Description Example Value
X-RateLimit-Limit Maximum API requests allowed in the rate limit window. 40
X-RateLimit-Remaining Remaining API requests in the current window before rate-limiting. 38
X-RateLimit-Reset UTC Unix epoch timestamp when the current rate limit window resets. 1783935293
X-Wallet-Credits Remaining prepaid credits in your wallet balance. 452
X-User-Tier The active account tier of the authenticated user. pro

Handling Rate Limit Exceptions

If your application exceeds the active rate limit or global cap of your account tier, the server will block further requests and return a 429 Too Many Requests HTTP response. Your application should capture this response status and implement retry-backoff algorithms.